Mobile phone generations (Protocols, Terminology,interfaces)

• Interfaces overview
• Protocols in GSM Networks
• Channels
• Traffic Channel
• Control channel or signaling channel
• OSI Introduction:
• SS7 Introduction:
• 2.5g
• 2.75g
• 3G
• Migration To 3G

3g Architecture:
UE (User Equipment)
Node B
RNC (Radio Network Controller)
Ggsn
Sgsn
Msc/vlr/Hlr
Interfaces overview
4G
4g architecture

• Migration To 4G
• 4g topology
• eNodeB
• MME (Mobility Management Entity)
• SGW (Serving Gateway)
• PGW (Packet Data Network Gateway)
• HSS (Home Subscriber Server)
• PCRF (Policy and Charging Rules Function) Server
• LTE Network Reference Model (with emphasis on pcrf)
• User plane protocol stacks

• control plane protocol stacks
• 5g
• 5g description:
• comparison between 4g and 5g
• Interfaces
• Attachments
• SCCP
• References

INTRODUCTION:
0G:
Mobile radio telephone systems
were telephone systems
of wireless type that preceded the
modern cellular mobile form
of telephony technology. Since they
were the predecessors of the first
generation of cellular telephones, these
systems are sometimes retroactively
referred to as pre-cellular (or
sometimes zero generation, that is, 0G)

1G
1G or (1-G) refers to the first generation of wireless
telephone technology (mobile telecommunications).
These are the analog telecommunication standards
that were introduced in 1979 and the early to mid-
1980s and continued until being replaced
by 2G digital telecommunications. The main
difference between the two mobile telephone
systems (1G and 2G), is that the radio signals used
by 1G network are analog, while 2G networks are
digital.

2G
• 2G (or 2-G) provides three primary benefits over their predecessors: phone
conversations are digitally encrypted; 2G systems are significantly more
efficient on the spectrum allowing for far greater mobile phone penetration
levels; and 2G introduced data services for mobile, starting with SMS (Short
Message Service) plain text-based messages. 2G technologies enable the
various mobile phone networks to provide the services such as text
messages, picture messages and MMS (Multimedia Message Service). It has 3
main services: Bearer services is one of them which is also known as data
services and communication.
• Second generation 2G cellular telecom networks were commercially
launched on the GSM standard in Finland by Radiolinja (now part of Elisa
Oyj) in 1991.Slide 9

2.5G
• 2.5G denotes 2G-systems that have implemented a packet-
switched domain in addition to the circuit-switched domain. It
doesn't necessarily provide faster service because bundling of
timeslots is used for circuit-switched data services (HSCSD) as
well.
• GPRS(General Packet Radio Service) is a packet oriented mobile
data standard on the 2G and 3G cellular communication
network's global system for mobile communications (GSM).

CIRCUIT VS PACKET DATA
Circuit Switched Service:
• 2G system (primarily voice and
data on circuit switched air
interface)
• Call charging based on channel
holding time.
• Maximum number of users per
TDMA channel is 8.
• Suitable for constant bit rate
applications
• Resource allocation is done such
that UL and DL are paired.
PACKET SWITCHED SERVICE:
• Several users can share the
same channel.
• Charges based on channel
usage (actual usage of byte
transferred).
• Well suited for bursty traffic.
• Resource allocation done
independently on UL and DL
(good for applications with
asymmetrical bit rate)
• Dynamic allocation of resources
• Can multiplex traffic (voice,
data, video).

GPRS SYSTEM FEATURE
• Variable quality of service.
• Independent packet routing.
• Protocol transparent (encapsulation
& tunneling)
• Slotted ALOHA for random access
procedure
• Provides IP connectivity to mobile
subscriber.
• Build on existing GSM infrastructure
with added nodes for supporting
packets.
 Serving GPRS Support Node (SGSN)

AIR INTERFACE - MOBILE
TERMINAL
• Type C GPRS only
(or manually switched between GPRS and
speech modes)
• Type B GPRS and Speech (not at same
time)
(Automatically switches between GPRS and
speech modes)
• Type A GPRS and Speech at the same time
GPRS ATTACH / DETACH
• Attach
Performed when the MS indicates its
presence to PLMN for the purpose of
using GPRS service
Carried out between MS and SGSN
MS identifies itself with its GSM identity
GPRS subscription necessary for
successful attach
• Detach
Performed when the MS indicates to the
PLMN that it no longer be using GPRS
services
MS identifies itself with its GSM identity

Mobile phone generations (Protocols, Terminology,interfaces)

SGSN
• Responsible for delivery of packets to mobile
subscribers in its service area.
• Mobility Management
• Logical link management, authentication
• GPRS user- related data needed by SGSN to
perform routing and transfer functionality stored
in GPRS Register eg current cell, current VLR, user
profile including IMSI and its address in PDN.
• Interface point between core and Radio
networks
GGSN
• Acts as an interface between GPRS network and
external PDNs
• Mainly responsible for packet routing, transfer
and mobility
management
 Converts packets from SGSN into appropriate
PDP format and
sends them out to corresponding PDN
 PDP addresses of incoming data packets from
PDN are
converted to IMSI of the destination user and sent
to the
responsible SGSN.
 Tunneling

2.75G
• Enhanced Data rates for GSM Evolution (EDGE) (also known
as Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC),
or Enhanced Data rates for Global Evolution) is a digital mobile
phone technology that allows improved data transmission rates
as a backward-compatible extension of GSM. EDGE is
considered a pre-3G radio technology and is part
of ITU's 3G definition. EDGE was deployed on GSM networks
beginning in 2003 – initially by Cingular (now AT&T) in the
United States.
• EDGE is standardized also by 3GPP as part of the GSM family. A
variant, so called Compact-EDGE, was developed for use in a
portion of Digital AMPS network spectrum.

3G
3G Vision
Universal global roaming
Multimedia (voice, data & video)
Increased data rates
384 Kbps while moving
2 Mbps when stationary at specific locations
Increased capacity (more spectrally efficient)
IP architecture
Problems
No killer application for wireless data as yet
Vendor-driven

REASONS TO SWITCH FROM 2G TO 3G
The main advantage of 3G technology is that is has much
higher data rate (384kbps up to 2 Mbps).
3G technology offers a high level of security as compared to
2G technology.
3G technologies provide improved telephone service and
significantly increased system capacity.Migration To 3G

4G
• 4G is the fourth generation of broadband cellular
network technology, succeeding 3G. A 4G system must provide
capabilities defined by ITU in IMT Advanced. Potential and current
applications include amended mobile web access, IP telephony,
gaming services, high-definition mobile TV, video conferencing,
and 3D television.
• It’s an upgrade for 3g by addressing the two major issues with the
platform: speed and network congestion.
• 4G is entirely IP based, which means it uses internet protocols even
for voice data.
• One of the aspects that makes 4G an upgrade to 3G is its higher
capacity. 4G can support a greater number of users, even at peak
times. For example, a 3G tower may only be able to give 100 people
the best possible connection speed, but a 4G tower can theoretically

5G
• 5G is the fifth generation cellular network technology.
• 5G wireless technology can change the way we use wireless gadgets by
providing very high bandwidth.
• 5G introduces a whole new concept of multi-path data path scheme for a real
wireless world, a complete wwww.
• There are plans to use millimeter waves for 5G.[2] Millimeter waves have shorter
range than microwaves, therefore the cells are limited to smaller size; The waves
also have trouble passing through building walls.Millimeter wave antennas are
smaller than the large antennas used in previous cellular networks. They are
only a few inches (several centimeters) long. Another technique used for
increasing the data rate is massive MIMO (multiple-input multiple-
output).[3] Each cell will have multiple antennas communicating with the wireless
device, received by multiple antennas in the device, thus multiple bitstreams of
data will be transmitted simultaneously, in parallel. In a technique
called beamforming the base station computer will continuously calculate the
best route for radio waves to reach each wireless device, and will organize
multiple antennas to work together as phased arrays to create beams of
millimeter waves to reach the device

• Description Of 2G(GSM):
Three primary benefits of 2G networks over their predecessors
were that:
• 1-phone conversations were digitally encrypted.
• 2-significantly more efficient use of the radio frequency
spectrum enabling more users per frequency band.
• 3-Data services for mobile, starting with SMS text messages.
• With General Packet Radio Service (GPRS), 2G offers a
theoretical maximum transfer speed of 50 kbit/s (40 kbit/s in
practice).
• With EDGE (Enhanced Data Rates for GSM Evolution), there is a
theoretical
• maximum transfer speed of 1 Mbit/s (500 kbit/s in practice).
• The most common 2G technology was the time division

A GSM NETWORK IS MADE UP OF THREE SUBSYSTEMS:
• THE MOBILE STATION (MS)
• THE BASE STATION SUB-SYSTEM (BSS) – COMPRISING A BSC AND
SEVERAL BTS
• THE NETWORK AND SWITCHING SUB-SYSTEM (NSS) – COMPRISING AN
MSC AND ASSOCIATED REGISTERS
• The interfaces defined between
each of these sub systems include:
• • 'A' interface between NSS and BSS
• • 'Abis' interface between BSC and
BTS (within the BSS)
• • 'Um' air interface between the BSS
and the MS

• We should know:
• Abbreviations:
• MSC – Mobile Switching Center
• BSS – Base Station Sub-system
• BSC – Base Station Controller
• HLR – Home Location Register
• BTS – Base Transceiver Station
• VLR – Visitor Location Register
• TRX – Transceiver
• AuC – Authentication Center
• MS – Mobile Station
• EIR – Equipment Identity Register
• OMC – Operations and Maintenance Center
• PSTN – Public Switched Telephone Network

MOBILE STATION(MS)
• The Mobile Station (MS) consists of the physical
equipment used by a
• PLMN subscriber to connect to the network. It comprises
the Mobile
• Equipment (ME) and the Subscriber Identity Module
(SIM). The ME
• forms part of the Mobile Termination (MT) which,
depending on the
• application and services, may also include various types
of Terminal

The mobile station consists of :
• mobile equipment (ME)
• subscriber identity module (SIM)
The SIM stores permanent and temporary data about the mobile,
the subscriber and the network, including :
• The International Mobile Subscribers Identity (IMSI)
• MS ISDN number of subscriber
• Authentication key (Ki) and algorithms for authentication check
*The mobile equipment has a unique International Mobile
Equipment Identity (IMEI), which is used by the EIR.

BASE STATION SUBSYSTEM (BSS)
The BSS comprises:
• Base Station Controller (BSC)
• One or more Base Transceiver Stations (BTSs)
The purpose of the BTS is to:
• provide radio access to the mobile stations
• manage the radio access aspects of the system
BTS contains:
• Radio Transmitter/Receiver (TRX)
• Signal processing and control equipment
• Antennas and feeder cables
The BSC:
• allocates a channel for the duration of a call
• maintains the call:
 monitors quality
 controls the power transmitted by the BTS or MS
 generates a handover to another cell when required

NSS TOPOLOGY
INTRODUCTION
Network Sub System can be considered as a heart of the GSM
Network. All the major activities like switching of calls, routing,
security functions, call handling, charging, operation &
maintenance, handover decisions, takes place within the
entities of NSS.
Various kinds of interfaces are used to communicate between the
different entities. Different methods are used to optimize and
provide the quality network with the minimum operating cost.

NETWORK SWITCHING SYSTEM (NSS)
The NSS combines the call
routing switches (MSCs and
GMSC)with database registers
required to keep track of
subscribers’ movements and
use of the system. Call
routing between MSCs is
taken via existing PSTN or
ISDN networks. Signaling
between the registers uses
Signaling System No. 7
protocol.
Functions of the MSC:
• Switching calls, controlling
calls and logging calls
• Interface with PSTN, ISDN,
PSPDN
• Mobility management over
the radio network and other
networks
• Radio Resource
management - handovers
between BSCs
• Billing Information

NETWORK SWITCHING SYSTEM (NSS)
These elements are
interconnected by
means of an SS7 network

MOBILE SWITCHING CENTER (MSC)
A mobile switching center (MSC) is the centerpiece of a network
switching subsystem (NSS). The MSC is mostly associated with
communications switching functions, such as call set-up, release,
and routing. However, it also performs a host of other duties,
including routing SMS messages, conference calls, fax, and service
billing as well as interfacing with other networks, such as the
public switched telephone network (PSTN) and Public Land Mobile
Network (PLMN).

HOME LOCATION REGISTER(HLR)
HLR is a database that stores subscription and set
of functions
needed to manage subscriber data in one PLMN
area. Any
administrative action by the service provider or
changes made
by subscriber is first carried out on the HLR and
then update the
VLR. Following are the subscriber data which
frequently
changes:
- Identification number MSISDN & IMSI
- Service restriction
- Teleservices

Beside the permanent data it
also include dynamic data of
home
subscriber including VLR address,
call forward number and call
barring numbers.
Triplets are also stored in the
HLR for the authentication
purpose.
The HLR communicates with
other nodes: VLR, AUC, GMSC &
SMS – SC
via MAP (Mobile Access Protocol).
To support this communication
HLR needs MTP and SCCP

VISITOR LOCATION REGISTER (VLR)
The VLR contains a copy of most of
the data stored at the HLR. It is,
however, temporary data which
exists for only as long as the
subscriber is “active” in the
particular area covered by the VLR.
The additional data stored in the
VLR in telecom is listed below:
Location Area Identity (LAI).
Temporary Mobile Subscriber
Identity (TMSI).
Mobile Station Roaming Number
(MSRN).
Mobile status (busy/free/no answer
• The VLR provides a local database
for the subscribers wherever they
are physically located within a
PLMN, this may or may not be the
“home” system. This function
eliminates the need for excessive
and time-consuming references to
the “home” HLR database.

VLR IS RESPONSIBLE FOR:
• Setting up and controlling
calls along with
supplementary services.
• Continuity of speech
(Handover)
• Location updating and
registration
• Updating the mobile
subscriber data.
• Maintain the security of the
subscriber by allocating TMSI
• Receiving and delivering
• Handling signaling to and
from
- BSC and MSs using
BSSMAP
- other networks eg PSTN,
ISDN using TUP
• IMEI check
• Retrieve data from HLR like
authentication data,
IMSI,ciphering key.

Retrieve information for
incoming calls.
• Retrieve information for
outgoing calls.
•Attach/Detach IMSI
• Search for mobile
subscriber, paging and
complete the call.

AUTHENTICATION CENTER (AUC)
The authentication center (AuC) is
a function
to authenticate each SIM card that
attempts to connect to
the gsm core network (typically
when the phone is powered on).
If authentication is not completed
user cant use the services of the
network. After authentication HLR
allowed to use services. When
authentication is completed a key
is generated that is used to
connect mobile user and gsm
network.
AUC is always integrated with HLR
for the purpose of the
authentication. At subscription
time, the Subscriber
Authentication Key (Ki) is
allocated to the subscriber,
together with the IMSI. The Ki is
stored in the AUC and used to
provide the triplets, same Ki is
also stored in the SIM.

AUTHENTICATION PROCEDURE:
The MSC/VLR transmits the
RAND (128 bits) to the mobile.
The MS computes the SRES (32
bits) using RAND, subscriber
authentication key Ki (128 bits)
and algorithm A3. MS sends
back this SERS to AUC and is
tested for validity.

EQUIPMENT IDENTIFICATION REGISTER (EIR)
Purpose of this feature is to make sure that no stolen or
unauthorized
mobile equipment is used in the network.
EIR is a database that stores a unique International Mobile
Equipment
Identity (IMEI) number for each item of mobile equipment.

PROCEDURE:
• The MSC/VLR requests the IMEI from the MS and
sends it to a
EIR.
• On request of IMEI, the EIR makes use of three
possible defined
lists:
 - A white list: containing all number of all
equipment identities
that have been allocated in the different participating
countries.
 - A black list: containing all equipment identities
that are
considered to be barred.
 - A grey list: containing (operator’s decision) faulty
or nonapproved
mobile equipment.
• Result is sent to MSC/VLR and influences the

INTERFACE
BSS Interfaces
• Air Interface: Radio Interface between the BTS
and
Mobile the supports frequency
hopping and
diversity.
• A Interface: Interface carried by a 2-Mb link
between
NSS and BSS. At this interface level,
transcoding takes place.
• Abis Interface:between Bts and Bsc.
interfaces

A-INTERFACE (MSC – BSC)
The interface between the MSC and its BSS is specified in the 08-
series
of GSM Technical Specifications. The BSS-MSC interface is used
to
carry information concerning:
• BSS management;
• call handling;
• mobility management.

B-INTERFACE (MSC – VLR)
The VLR is the location and management data base for the
mobile
subscribers roaming in the area controlled by the associated
MSC(s). Whenever the MSC needs data related to a given mobile
station currently located in its area, it interrogates the VLR. When
a mobile station initiates a location updating procedure with an
MSC, the MSC informs its VLR which stores the relevant
information. This procedure occurs whenever an MS roams to
another location area. Also, when a subscriber activates a
specific
supplementary service or modifies some data attached to a
service, the MSC informs (via the VLR) the HLR which stores

C-INTERFACE (HLR - MSC)
The Gateway MSC must interrogate the HLR of the required
subscriber
to obtain routing information for a call or a short message
directed to
that subscriber.

D-INTERFACE (HLR - VLR)
This interface is used to exchange the data related to the
location of the
mobile station and to the management of the subscriber. The
main
service provided to the mobile subscriber is the capability to set
up or
to receive calls within the whole service area. To support this, the
location registers have to exchange data. The VLR informs the
HLR of
the location of a mobile station managed by the latter and
provides it
(either at location updating or at call set-up) with the roaming

The HLR sends to the VLR all the data needed to support the service to
the mobile subscriber. The HLR then instructs the previous VLR to
cancel the location registration of this subscriber. Exchanges of data
may occur when the mobile subscriber requires a particular service,
when he wants to change some data attached to his subscription or
when some parameters of the subscription are modified by
administrative means

E-INTERFACE (MSC - MSC)
When a mobile station moves from one MSC area to another
during a call, a handover procedure has to be performed in
order to continue the communication. For that purpose the
MSCs have to exchange data to initiate and then to realize the
operation. After the handover operation has been completed, the
MSCs will exchange information to transfer A-interface
signaling as necessary…. When a short message is to be
transferred between a Mobile Station and Short Message Service
Centre (SC), in either direction, this interface is used to transfer
the message between the MSC serving the Mobile Station and
the MSC which acts as the interface to the SC.

F-INTERFACE (MSC -
EIR)
This interface is used
between MSC and EIR to
exchange data, in order
that the EIR can verify
the status of the IMEI
retrieved from the
Mobile
Station.
G-INTERFACE (VLR -
VLR)
When a mobile
subscriber moves from
a VLR area to another
Location
Registration procedure
will happen. This
procedure may include
the
retrieval of the IMSI and
authentication
parameters from the old
VLR.
H-INTERFACE (HLR
- AUC)
When an HLR receives a
request for
authentication and
ciphering data
for a Mobile Subscriber
and it does not hold the
requested data, the
HLR requests the data
from the AuC. The
protocol used to
transfer
the data over this
interface is not
standardized….

GSM SIGNALING MATRIX
• MSC uses ISUP/TUP protocols
for PSTN signaling.
• MAP signalling for database
applications like HLR, VLR, EIR,
AUC, SMS-SC, GMSC.
• GSM specific protocol as
BSSAP, which comprises of DTAP
and BSSMAP.
• The BSC on layer 2 uses LAPD
protocol, which is an ISDN.
• BTS has LAPDm as layer 2
protocol.
• Mobile has DTAP for MSC and
RR for Radio Resource signaling.

MAP (MOBILE APPLICATION PART)
MAP is a protocol specially designed for GSM requirement. It is installed
in MSC, VLR, HLR, EIR and communicates in case of:
• Location registration
• Location cancellation
• Handling/management/ retrieval of subscriber data.
• Handover
• Transfer of security/ authentication data.
 MAP is defined by two different standards, depending upon the mobile
network type:
MAP for GSM (prior to Release 4) is specified by 3GPP TS 09.02 (MAP v1, MAP
v2)
MAP for UMTS ("3G") and GSM (Release 99 and later) is specified by 3GPP TS
29.002 (MAP v3)

BSS APPLICATION PART (BSSAP: BASE
STATION SYSTEM APPLICATION PART)
• BSSAP is used for signaling between MSC/VLR and BSS. Three groups of
signals belong to BSSAP
1. DTAP
2. BSSMAP
3. Initial MS messages
The BSSAP supports both connectionless and connection-oriented services
provided by the SCCP. The connectionless services are used to support global
procedure such as PAGING (for MS) and RESET (a circuit). The connection-
oriented services are used for dedicated procedures such as handover and
assignment procedures. The BSSAP supports messages sent between the MSC
and the BSS, as well as transparent message transfer between the MSC and the
MS. To enable this functionality, the BSSAP is divided into two parts, i.e., the
Base Station Subsystem Management Application Part (BSSMAP) and Direct
Transfer Application Part (DTAP).

DIRECT TRANSFER APPLICATION PART
(DTAP)
DTAP is a messages between the MSC and MS, passes through the BSS
transparently. These are call control and mobility management
messages directed towards a specific mobile.
3 main type of DTAP messages are:
• Messages for mobility management like location update, authentication,
identity request
• Messages for circuit mode connections call control
• Messages for supplementary services

BSSMAP
BSS management messages (BSSMAP) between MSC and BSS
(BSC/ BTS),
which are necessary for resource management, handover control,
paging
order etc. The BSSMAP messages can either be connection less or
connection oriented.

INITIAL MS MESSAGES
These messages are passed unchanged through BSS, but BSS
analyses part of the messages and is not transparent like DTAP
messages.
Between BSS and MSC, the initial MS message is transferred in the
layer 3 information in the BSSMAP.
The Initial MS messages are:
• CM Request
• Location update request
• Paging response

LAPD
All signaling messages on the Abis
interface use the Link Access
Procedures on the D-channel. (LAPD
protocol). LAPD provides two kinds of
signaling:
• unacknowledged information
• acknowledged information
LAPD link handling is a basic
function to provide data links on
the 64 kbps
physical connections between BSC

LAPD has three sub signaling
channels
1. RSL (Radio signaling Link),
deals with traffic management,
TRX signaling.
2. OML (Operation &
Maintenance Link), serves for
maintenance related info and
transmission of traffic statistics.
3. L2M (Layer 2 Management),
used for management of the
different signaling on the same
time slot.

LAPD FRAME STRUCTURE
LAPD Frame structure is made up of:
Flag: Indicates the beginning and end of each
frame unit. Flag has
a pattern of 01111110.
FCS: Frame Check Sequence, provides the error
checking for the
frame. If error is found frame will be
retransmitted.
Command: It has two types of structure, in
acknowledge mode it
has N(S) and N(R ). N(S) is a sequence number of
frame sent
and N(R ) is the sequence number of the frame
expected to
receive next.

C/R: This bit indicates whether it is command or response.
P/F: In command frames, the P/F bit is referred to as the P bit and
the other end transmits the response by setting this bit to F.
TEI: Terminal Endpoint Identifier, is a unique identification of each
physical entity on either side like each TRX within a BTS have a
unique TEI.
SAPI: Service Access Point Identifier, used to identify the type of link.
SAPI = 0 for RSL
SAPI = 62 for OML
SAPI = 63 for L2ML
Each LAPD link is identify by SAPI/TEI pair.

LAPDM
Link Access Procedures on the Dm channel
(LAPDm) is the layer 2 protocol used to
convey signaling information between layer
3 entities across the radio interface. Dm
channel refers to the control channels,
independent of the type including
broadcast, common or dedicated control
channels.
LAPDm is based on the ISDN protocol LAPD,
used on the Abis interface. Due to the radio
environment, the LAPD protocol can not be
used in its original form. Therefore, LAPDm
segments the message into a number of
shorter messages.

LAPDm functions include:
• LAPDm provides one or more data link connections on a
Dm channel. Data Link Connection Identifier (DLCI) is used for
discriminating between data link connections.
• It allows layer 3 message units be delivered transparently
between layer 3 entities.
• It provides sequence control to maintain the sequential order
of
frames across the data link connections.

LAPDM FRAME STRUCTURE
Sequence Number: N(S) send se quence number of the
transmitted frame. N(R) is receive sequence number.
P/F : All frames contain the Poll/Final bit. In command
frames, the
P/F bit is referred to as the P bit. In response frames, the
P/F bit
is referred to as the F bit.
Service Access Point Identifier: Service Access Points
(SAPs) of a
layer are defined as gates through which services are
offered to
an adjacent higher layer.SAP is identified with the Service
Access Point Identifier (SAPI).
SAPI = 0 for normal signaling of DTAP & RR
SAPI = 3 for short message services
LAPDm has no error detection and correction. It is used in
two modes:
• Acknowledge &
• Unacknowledged
and having a different structure for both.

CHANNELS
Introduction
• In telecommunications a channel, refers either to
a physical
transmission medium such as a wire, or to a logical
connection
over a multiplexed medium such as a radio channel.
• The channel used in the air interface is divided
into two types:
Physical channel and Logical channel.
• Physical channel : It is the medium over which the
information
is carried.
• Logical channel : It consist of information carried
over a
physical channel.

PHYSICAL CHANNEL
• When an MS and a BTS
communicate, they do so on a
specific pair of radio frequency
(RF) carriers, one for the up-link
and the other for the down-link
transmissions, and within a given
time slot. This combination of
time slot and carrier frequency
forms what is termed a physical
channel .
• One RF channel will support
eight physical channels in time
slots zero through seven.
LOGICAL CHANNELS
It transports either user data
during a call or signalling
information for MS or base
station.
• The data, whether user traffic or
signalling information, are
mapped onto the physical
channels by defining a number of
logical channels .
• Two groups of logical channels:
• Traffic Channels, for call data
• Control channels, to
communicate service data
between network equipment

TRAFFIC CHANNEL
• Traffic channel (TCH) : Traffic channels are
intended to
carry encoded speech and user data.
-Full rate traffic channels at a net bit rate of 22.8
Kb/s
(TCH/F)
-Half rate traffic channels at a net bit rate of 11.4
Kb/s
(TCH/H)
Speech Channels : Speech channels are defined
for both
full rate and half rate traffic channels.
Data Channels : Data channels support a variety of
data
rates (2.4, 4.8 and 9.6 Kb/s) on both half and full
rate
traffic channels. The 9.6 Kb/s data rate is only for
full

CONTROL CHANNEL OR SIGNALING
CHANNEL
• Control channels carry signalling information
between an
MS and a BTS. There are several forms of control
channels
in GSM, and they can generally be divided into three
categories according to the manner in which they are
supported on the radio interface and the type of
signalling
information they carry.
1.Broadcast control channel
2.Common control channel
3.Dedicated control channel

BROADCAST
CONTROL
CHANNELS
• Broadcast control channels are
transmitted in
downlink direction only i.e. only
transmitted by
BTS.
• The broadcast channels are used to
broadcast
synchronization and general network
information
to all the MSs within a cell.
• Such as Location Area Identity (LAI)
and
maximum output power.
• It has three types
1. FCCH FREQUENCY CORRECTION
CHANNEL
2. SCH SYNCHRONISATION CHANNEL
3. BCCH BROADCAST CONTROL
CHANNEL
COMMON CONTROL
CHANNEL
• The common control channels
are used by an MS during the
paging and access procedures.
• Common control channels are of
following types
• Random Access Control Channel
(RACH)
• Paging Channel (PCH)
• Access Grant Control Channel
(AGCH)
• Cell Broadcast Channel (CBCH)
DEDICATED
CONTROL CHANNEL
Signalling information is carried between an
MS and a BTS using associated and dedicated
control channels during or not during a call.
• The are of following type :-
• Standalone Dedicated Control Channel
(SDCCH)
• Associated Control Channel (ACCH)
• Slow Associated Control Channel (SACCH)
• Fast Associated Control Channel (FACCH)

BROADCAST CHANNEL
FREQUENCY
CORRECTION
CHANNEL (FCCH)
 - Used for the frequency
correction / synchronization of
a mobile station.
 - The repeated (every 10 sec)
transmission of Frequency
Bursts is called FCCH.
 - FCCH is transmitted on the
downlink, point-to-multipoint.
SYNCHRONIZATION
CHANNEL (SCH)
 - Allows the mobile station to
synchronize time wise with the
BTS.
 - Repeated broadcast (every 10
frames) of Synchronization
Bursts is called (SCH)
 - SCH is transmitted on the
downlink, point to multipoint.
BROADCAST
CONTROL
CHANNEL(BCCH)
 - The broadcast control
channel(BCCH) is used to
broadcast control information
to every MS within a cell.
 - This information includes
details of the control channel
configuration used at the BTS,
a list of the BCCH carrier
frequencies used at the
neighbouring BTSs and a
number of parameters that are
used by the MS when accessing
the BTS.
 - BCCH is transmitted On the
downlink, point-to-multipoint.

CCCH
COMMON CONTROL
CHANNEL
Random Access Control Channel
(RACH)
Transmitted by the mobile when it
wishes to access to the system
This occurs when mobile initiates a
call or responds to a page.
Paging Channel (PCH)
Transmitted by the BTS when it
wishes to contact a mobile.
The reason for contact may be an
incoming call or short message.

Access Grant Control Channel
(AGCH)
It carries data which instructs
the mobile to operate in a
particular physical channel
(Time slot).
The AGCH is used by the
network to grant, or deny, an
MS access to the network by
supplying it with details of a
dedicated channel, i.e. TCH
or SDCCH, to be used for
subsequent communications
Cell Broadcast Channel (CBH)
This channel is used to
transmit messages to be
broadcast to all
mobiles within a cell e.g. traffic
info.
The CBCH will steal time
from SDCCH.

DCH
STANDALONE DEDICATED
CONTROL CHANNEL (SDCCH)
• The MS is on the SDCCH
informed about which physical
channel (frequency and time slot)
to use for traffic (TCH).
• It also carries information for
call forwarding and Transmission
of short message.
ASSOCIATED CONTROL
CHANNEL (ACCH)
• These Channel Could be
associated with either a SDCCH or
a TCH.
• They are used for carrying out
information associated with the
process being carried out on
either SDCCH or TCH.
• They are of two type
1. Fast ACCH
2. Slow ACCH

SLOW ASSOCIATED CONTROL
CHANNEL (SACCH)
• Conveys power control and
timing information in the
downlink
direction.
• Receive signal strength
Indicator and link quality
report in uplink
direction.
• It occupies one timeslot in
every 26. SACCH messages
may be sent once
FAST ASSOCIATED CONTROL
CHANNEL (FACCH)
• FACCH is transmitted instead
of a TCH.
• The FACCH steal the TCH
bust and inserts its own
information.
• The FACCH is used to carry
out user authentication and
handover.
• A complete FACCH message
may be sent once in every 20
ms.

OSI
INTRODUCTION:
• The Open Systems Interconnection
model (OSI model) is a conceptual
model that characterizes and standardizes
the communication functions of
a telecommunication or computing
system without regard to its underlying
internal structure and technology.
• Its goal is the interoperability of diverse
communication systems with
standard communication protocols.
• The model partitions a communication
system into abstraction layers.
• The original version of the model had
seven layers.
• A layer serves the layer above it and is
served by the layer below it.

LAYER 7: APPLICATION LAYER
• The application layer is the OSI layer closest to the
end user, which means both the OSI application layer
and the user interact directly with the software
application.
•Contains protocols that allow the users to access the
network (FTP, HTTP, SMTP, etc)
• • Does not include application programs such as
email, browsers, word processing applications, etc.
• • Protocols contain utilities and network-based
services that support email via SMTP, Internet access
via HTTP, file transfer via FTP, etc

LAYER 6: PRESENTATION LAYER
Responsibilities of this layer are:
• Translation
• Different computers use different encoding systems
(bit order translation)
• Convert data into a common format before
transmitting.
• Syntax represents info such as character codes - how
many bits to represent data – 8 or 7 bits
• Compression – reduce number of bits to be transmitted
• Encryption – transform data into an unintelligible format
at the sending end for data security
• Decryption – at the receiving end

LAYER5:SESSION LAYER
• The session layer controls the dialogues
(connections) between computers. It establishes,
manages and terminates the connections between
the local and remote application.
• Main functions of this layer are:
• • Dialog control – allows two systems to enter into a
dialog, keep a track of whose turn it is to transmit
• • Synchronization – adds check points
(synchronization points) into stream of data.

LAYER 4: TRANSPORT LAYER
• The transport layer provides the functional and
procedural means of transferring variable-
length data sequences from a source to a
destination host, while maintaining the quality
of service functions.
• • Responsible for source-to destination delivery
of the entire message
• • Segmentation and reassembly – divide
message into smaller segments, number them
and transmit. Reassemble these messages at the
receiving end.

LAYER 3: NETWORK LAYER
• The network layer provides the functional and
procedural means of transferring variable
length data sequences (called packets) from one
node to another connected in "different
networks“.
• • Responsible for delivery of packets across
multiple networks
• • Routing – Provide mechanisms to transmit
data over independent networks that are linked
together.
• • Network layer is responsible only for delivery
of individual packets and it does not recognize

LAYER2:DATA LINK LAYER
• The data link layer provides node-to-node data transfer—a link
between two directly connected nodes.
Main functions of this layer are:
• Framing – divides the stream of bits received from network
layer into manageable data units called frames.
• Physical Addressing – Add a header to the frame to define the
physical address of the source and the destination machines.
• Flow control – Impose a flow control – control rate at which data
is transmitted so as not to flood the receiver (Feedbackbased flow
control)
• Error Control – Adds mechanisms to detect and retransmit
damaged or lost frames. This is achieved by adding a trailer to
the end of a frame
• IEEE 802 divides the data link layer into two sublayers:
1. Medium access control (MAC) layer – responsible for
controlling how devices in a network gain access to a medium
and permission to transmit data.
2. Logical link control (LLC) layer – responsible for identifying

LAYER 1: PHYSICAL LAYER
The physical layer is responsible for the transmission
and reception of unstructured raw data between a
device and a physical transmission medium.
Functions of Physical Layer:
• Bit representation – encode bits into electrical or
optical signals
• Transmission rate – The number of bits sent each
second
• Physical characteristics of transmission media
• Synchronizing the sender and receiver clocks
• Transmission mode – simplex, half-duplex, full
duplex

SS7
INTRODUCTION:
Common Channel Signaling System No. 7 (i.e., SS7 or C7 ) is a
global standard for telecommunications defined by the
International Telecommunication Union (ITU)Telecommunication
Standardization Sector (ITU-T). The standard defines the
procedures and protocol by which network elements in the
public switched telephone network (PSTN) exchange information
over a digital signaling network to effect wireless (cellular) and
wire line call setup, routing and control.

THE SS7 NETWORK AND PROTOCOL ARE
USED FOR:
• basic call setup, management,
and tear down wireless services
such as personal communications
services (PCS), wireless roaming,
and mobile subscriber
authentication
• local number portability (LNP)
• enhanced call features such as
call forwarding, calling party
name/number display, and three-
way calling
• efficient and secure worldwide

SIGNALING TYPES
THERE ARE TWO TYPES OF SIGNALING :
1. CHANNEL ASSOCIATED
SIGNALING (CAS)
Channel Associated
Signaling: signaling is
always sent on the
same connection as
that of speech.The
Signaling is associated
with speech.
2. COMMON CHANNEL
SIGNALING (CCS7)
Common Channel Signaling:
signaling network is separated
from the speech network.Every
signaling information will have a
label which indicates to which
speech connection this signaling
information belongs to.The
signaling channel has no
specific position (timeslot).The
same signaling channel carries
information for all speech
circuits as and when required
basis.

ADVANTAGE OF CCS7 OVER CAS
* A dedicated signaling link required for each speech channel in CAS e.g. 3
channels in 3 PCMs : CCS 7 uses only 1 channel for a number of PCMs
* CAS is slow, so longer call setup times : CCS 7 - 64kbps fast & efficient.
* In CAS, no possibility of signaling during the “talking phase” : CCS 7
signaling is independent of speech.
* CAS supports limited set of signals : CCS 7 supports signal units of variable
length max. 279 octets - so much more signaling info can be exchanged
than is possible with CAS.
* Usage of messages instead of pre-defined bit patterns enables to transfer
call related signaling info (call establishment) as well as non call related call
info ( location update , handover , short messages etc.)
* CCS 7 - modular ; easy introduction of new & advanced services.

MESSAGE TRANSFER PART (MTP)
• Function:
• to provide a reliable transfer and delivery of signaling information across the signaling
network and to have the ability to react and take necessary actions in response to system
and network failures to ensure that reliable transfer is maintained.
• Includes the functions of layers 1 to 3 of the OSI reference model.
• User functions in CCS 7 MTP terms are:
– the ISDN User Part (ISUP)
– the Telephone User Part (TUP)
the signaling Connection Control Part (SCCP)
– the Data User Part (DUP)
• The SCCP also has Users. These are:
– the ISDN User Part (ISUP)
– Transaction Capabilities (TC)
– Operations Maintenance and Administration Part (OMAP)

FUNCTIONS OF MTP
SIGNALING DATA LINK (MTP LEVEL 1 )
• Defines the physical, electrical and functional characteristics and the
physical interface towards the transmission medium (PCM30)
• signaling Data Link is a bi-directional transmission path for signaling
consisting of two data channels operating together in opposite
directions at the same data rate.
• Digital : 64 kbps channels. For PCM30 HDB3 coding is used
- Minimum allowed bit rate for telephone call control application :
4.8kbps

SIGNALING LINK FUNCTIONS (MTP LEVEL 2)
Together with signaling data link, the signaling link functions
provide a
signaling link for the reliable transfer of signaling messages
between
two adjacent signaling points.
• Messages are transferred over signaling link in variable length
messages called signal Units which contain additional
information to
guarantee a secure transmission.

FUNCTIONS:
• Delimitation of signaling units by means of Flags.
• Flag limitation prevention by bit stuffing.
• Error detection by means of Check bits included in each
signaling unit.
• Error control by re-transmission and signaling unit sequence
control by means of sequence numbers and continuous ACKs
• Signaling link failure detection by signaling unit error rate
monitoring and signaling link recovery by special procedures.

SIGNALING NETWORK FUNCTIONS (MTP
LEVEL 3)
• Level 3 in principle defines those transport functions and
procedures that are common to and independent of the
operation of individual signaling links.
These functions fall into two major categories:
Signaling message handling functions – These transfer the
message to the proper signaling link or User Part.The main
functions are:-
• Message discrimination function
• Message distribution function
• Message routing function

signaling network management functions – These control the
current
message routing and configuration of the signaling network
facilities
and in the case of signaling network failures, control the
reconfigurations and other actions to preserve or restore the
normal
message transfer capability. Contains signaling link
management,
traffic management and route management.The main functions
are:-
• Signaling link management

MTP USER FUNCTIONS (LEVEL 4)
User Parts defines the functions and procedures of the signaling system that are particular
to a certain type of user of the system.
The following entities are defined as User Parts in CCS 7.
• Telephone User Part (TUP)
• The TUP Recommendations define the international telephone call control signaling
functions for use over CCS 7.
• Data User Part (DUP)
• The Data User Part defines the protocol to control interexchange circuits used on data
calls, and data call
facility registration and cancellation.

ISDN User Part (ISUP)
• The ISUP encompasses signaling functions required to provide
switched services and user facilities for voice and non-voice
applications in the ISDN.
Signaling Connection Control Part (SCCP)
link
• The SCCP provides additional functions to the Message Transfer Part
to provide connectionless and connectionoriented network services to
transfer circuit-related, and noncircuit-related signaling information.
• Key Enhancements by SCCP

• Enhanced Addressing Capability.
• upto 255 users can be addressed by the use of Subsystem
Numbers (SSN).
• SCCP provides a routing function which allows signaling messages
to be routed to a signaling point based on, for example, dialled digits.
This capability involves a translation function which translates the
global title (e.g. dialled digits) into a signaling point code and a sub-
system number.
• Connectionless and Connection-Oriented Services
• Class 0 : basic connectionless service
• Class 1 : sequenced connectionless service
• Class 2 : basic connection-oriented service
• Class 3 : flow control connection-oriented service

TCAP
• TCAP provides services for non-circuit related services .
TCAP receives messages from SCCP and routes it to the user .
TCAP makes it possible to have several transactions running
simultaneously.
• TCAP consists of component sub-layer and the transaction
sublayer. The component layer provides information exchange
between two layers by the means of dialogues. A dialogue will
contain several components like action , response etc . The
transaction identifier gives each transaction a unique identity
which is also known as transaction identifier.
• TCAP acts as a secretary to a manager who has several
engineers reporting to it. The secretary handles all the
transactions from the manager and sends it across the
appropriate engineer and also keeps track of each transactions

MIGRATION TO 3G
CDMA
GSM
TDMA
PHS
(IP-Based)
64 Kbps
GPRS
115 Kbps
CDMA 1xRTT
144 Kbps
EDGE
384 Kbps
cdma2000
1X-EV-DV
Over 2.4 Mbps
W-CDMA
(UMTS)
Up to 2 Mbps
2G
2.5G
2.75G 3G
1992 - 2000+
2001+
2003+
1G
1984 - 1996+
2003 - 2004+
TACS
NMT
AMPS
GSM/
GPRS
(Overlay)
115 Kbps
9.6 Kbps
9.6 Kbps
14.4 Kbps
/ 64 Kbps
9.6 Kbps
PDC
Analog Voice
Digital Voice
Packet Data
Intermediate
Multimedia
Multimedia
PHS
TD-SCDMA
2 Mbps?
9.6 Kbps
iDEN
(Overlay)
iDEN
Source: U.S. Bancorp Piper Jaffray

GSM EVOLUTION FOR DATA ACCESS
1997 2000 2003 2003+
GSM
GPRS
EDGE
UMTS
9.6 kbps
115 kbps
384 kbps
GSM evolution 3G

COMPARISON BETWEEN 2G AND 3G
STRUCTURE
SS7
IP/ATM
BTS
BSC
MSC Server
VLR
HLR
AuC
GMSC server
BSS
SGSN GGSN
PSTN
PSDN
CN
C
D
Gc
Gr
Gn Gi
Gb
Abis
Gs
B
H
BSS Base Station System
BTS Base Transceiver Station
BSC Base Station Controller
RNS Radio Network System
RNC Radio Network Controller
CN Core Network
MSC Mobile-service Switching Controller
VLR Visitor Location Register
HLR Home Location Register
AuC Authentication Server
GMSC Gateway MSC
SGSN Serving GPRS Support Node
GGSN Gateway GPRS Support Node
A
Nc
2G MS (voice only)
2G+ MS (voice & data)
Node B
RNC
RNS
Iub
IuCS
IuPS
3G UE (voice & data)
Mc
CS-MGW
CS-MGW
Nb
PSTN
Mc
ATM

UE (USER EQUIPMENT)THE UE IS THE HARDWARE THAT A
USER USES TO ACCESS THE NETWORK.
EXAMPLE- MOBILE.
IT IS CONSISTED OF ME (MOBILE
EQUIPMENT) AND USIM(UTMS
SUBSCRIBER IDENTITY MODULE).
THE USIM IS A SMARTCARD THAT
HOLDS THE SUBSCRIBER IDENTITY,
PERFORMS AUTHENTICATION
ALGORITHMS, AND STORES
AUTHENTICATION AND ENCRYPTION
KEYS AND SOME SUBSCRIPTION
INFORMATION THAT IS NEEDED AT
THE TERMINAL.

NODE B
Communicates directly with
UE.
Is controlled by an RNC
(Radio Network Controller).
Sends voice information and
data and control signaling to
the UE(User Equipment).
Assigns and maintains the
voice channels through which
the UE communicates with
another user.

DIFFERENCES BETWEEN A NODE B AND A GSM
BASE STATION
• Frequency use
• The utilization of WCDMA
technology allows cells belonging
to the same or different Node Bs
and even controlled by
different RNC to overlap and still
use the same frequency (in fact, the
whole network can be implemented
with just one frequency pair). The
effect is utilized in soft handovers.
• Power requirements
• Since WCDMA often operates at higher
frequencies than GSM (2,100 MHz as opposed
to 900 MHz for GSM), the cell radius can be
considerably smaller for WCDMA than for GSM
cells as the path loss is frequency dependent.
WCDMA now has networks operating in the
850–900 MHz band. In these networks, at
these frequencies, the coverage of WCDMA is
considered better than that of the equivalent
GSM network.
• Unlike in GSM, the cells' size is not constant (a
phenomenon known as "cell breathing"). This
requires a larger number of Node Bs and
careful planning in 3G (UMTS) networks. Power
requirements on Node Bs and user equipment
(UE) are much lower.

RNC (RADIO NETWORK CONTROLLER)
Controls Node B.
Provides Soft hand-off.
Manages radio channels and the
terrestrial channels.
Each RNC is connected to a
SGSN the packet switched part
of the core network through the
Iups interface, thus provides
internet usage option to the
UEs.
The RNC carries out radio
resource management, some of
the mobility
management functions and is
the point where encryption is

GGSN
• The gateway GPRS support
node (GGSN) is a main
component of the GPRS
network. The GGSN is
responsible for the
internetworking between the
GPRS network and external
packet switched networks,
such as the Internet or
an X.25 network.
A Gateway GPRS Support Node
(GGSN) is part of the core network
that connects GSM-based 3G
networks to the Internet. The
GGSN, sometimes known as a
wireless router, works in tandem
with the Serving GPRS Support
Node (SGSN) to keep mobile users
connected to the Internet and IP-
based applications.
The GGSN converts incoming data
traffic from mobile users (via the
SGSN) and forwards it to the
relevant network, and vice versa.

SGSN
• The Serving GPRS Support Node
(SGSN) is the node that is serving
the MS/UE. The SGSN
supports GPRS and/or UMTS.] The
SGSN keeps track of the location of
an individual MS/UE and performs
security functions and access
control. which handles all
packet switched data within
the network, e.g. the mobility
management and
authentication of the users.
The SGSN performs the same
• Common SGSN functions
• Detunnel GTP packets from the GGSN
(downlink).
• Tunnel IP packets toward the GGSN (uplink).
• Carry out mobility management when a
standby mode mobile moves from one
routing area to another routing area
• Billing a user according to data used.
• Mobile Equipment Identity Check Procedure.
• The SMS GMSCs and SMS IWMSCs support
SMS transmission via the SGSN.
• The Offline Charging System (OFCS) collects
charging records from SGSNs.
• The SGSN contains mechanisms for avoiding
and handling overload situations.
• The SGSN communicate with other SGSN(s)
and/or MME(s) (Mobility Management

MSC/VLR/HLR
• Has same function in gsm so
we don't repeat it again.
• Go to :Mobile Switching
Center (MSC)
• Home Location Register(HLR)
• Visitor Location Register (VLR)

INTERFACES OVERVIEW
IUB
The Iur interface allows
communication between
different RNCs within the
UTRAN.
IUR
The interface between
the RNC and the Circuit
Switched Core Network
(CS-CN) is called Iu-CS.
THE IUB CONNECTS THE
NODE B AND THE RNC
WITHIN THE UTRAN.
IU-CS IU-PS
The interface between the RNC and
the Packet Switched Core Network is
called Iu-PS.
interfaces

PROTOCOLS
• The protocol architecture of UTRAN is
subdivided into three layers:
• 1. Transport Network Layer. Physical and
transport protocols and functions to provide
AAL2 resources and allow communication
within UTRAN and CN. The protocols are not
UMTS specific.
• 2. Radio Network Layer. Protocols and
functions to allow management of radio
interface and communication between
UTRAN components and between UTRAN
and UE.
• 3. System Network Layer. NAS protocols to
allow communication between CN and UE.
• Each of the layers is divided into a control
and a user plane.
• Control plane: Transmission of control
signaling information.

IUB – CONTROL PLANETHE PROTOCOL STACKS OF UU AND IUB INTERFACES – CONTROL PLANE
– CONTAIN
• ATM: Asynchronous Transfer Mode is
used in UMTS as the transmission form on
all Iu interfaces. The physical layer is SDH
over fiber. The smallest unit in ATM s the
ATM cell. It will be transmitted in the
Virtual Channel. Many virtual channels are
running within a Virtual Path.
• AAL: ATMAdaptation Layer – To transmit
higher protocols via ATM, it is required to
have adaptation sublayers. These
sublayers contain a common adaptation
and a service-specific adaptation part.
• UPFP: User Plane Framing Protocol – Used
on Iur and Iub interfaces to frame
channels supported between SRNC and
Node Bs.

• SSCOP :Service Specific Connection Oriented
Protocol Provides mechanisms for
establishment and release of connections and
reliable exchange of signaling information
between signaling entities.
• MAC: Medium Access Control Protocol –
Coordinates access to physical layer. Logical
channels of higher layers are mapped onto
transport channels of lower layers. MAC also
selects appropriate TFSs depending on
necessary transmission rateb and organizes the
priority handling between different data flows
of one single UE.
• RLC: Radio Link Control Protocol –Offers
transport services to the higher layers called
Radio Bearer Services; the threework modes are
transparent, acknowledged, and
unacknowledged mode.
• SSCF: Service Specific Coordination Function
(User-Network-I/F, Network-Network- 1/F) –
Not a protocol but an internal coordination
function, which does internal adaptation of the
information coming or going to higher layers,
for example, MTP3-B routing information.
• STC: Signaling Transport Converter – An
internal function, which has no own messages;
• RRC: Radio Resource Control Protocol – A sublayer of
Layer 3 on UMTS radio interface and exists in the
control plane only. It provides information transfer
service to the NAS and is responsible for controlling
the configuration of UMTS radio interface layers 1 and
2.
• AAL2L3: AAL2 Layer 3 Protocol – Generic name for
transport signaling protocol to set up and release
transport bearers. In UMTS the main ALCAP protocol
is the AAL2 signaling protocol.
• NBAP: Node B Application Part – Protocol used
between RNC and Node B to configure and manage
the Node B and set up channels on Iub and Uu
interfaces.
• MM: Mobility Management – A generic term for the
specific mobility functions provided by
aPLMNincluding, e.g., tracking a mobile as it moves
around a network and ensuring that communication is
maintained.
• SM: Session Management – Protocol used between UE
and SGSN and creates, modifies, monitors, and
terminates sessions with one or more participants,
including multimedia and Internet telephone calls.
• CC: Call Control – includes some basic procedures for
mobile call control (no transport control!): Call
Establishment, Call Clearing, Call Information Phase,

IUB – USER PLANE
THE USER PLANE PROTOCOL STACKS OF UU AND IUB INTERFACES
INTRODUCE SOME NEW LAYERS
• PDCP: Packet Data Convergence
Protocol – Used to format data into
a suitable structure prior to transfer
over the air interface and provides
its services to the NAS at the UE or
the relay at the RNC.
• BMC: Broadcast/Multicast Protocol –
Adapts broadcast and multicast
services on the radio interface and
is a sublayer of L2 that exists in the
user plane only.

IUR – USER/CONTROL PLANE
THE IUR INTERFACE BETWEEN RNCS SHOWS TWO ALTERNATIVE SOLUTIONS ON THE
TRANSPORT NETWORK
LAYER: EITHER SCCP AND RNSAP MESSAGES CAN BE TRANSPORTED USING MTP3-B RUNNING
ON TOP OF
SSCOP, OR IT IS POSSIBLE TO RUN SCCP ON TOP OF M3UA IF THE LOWER TRANSPORT LAYER
IS IP-BASED.
• IP: Internet Protocol – Provides
connectionless services between
networks and includes features for
addressing, type-of-service
specification, fragmentation and
reassembly, and security.
• SCTP: Stream Control Transmission
Protocol – Transport protocol that
provides acknowledged error-free
nonduplicated transfer of data. Data
corruption, loss of data, and
duplication of data are detected by

• MTP3-B: Message Transfer Part Level 3 Broadband – Fulfills the same
sort of work as the standard narrowband MTP; it provides
identification and transport of higher layer messages (PDUs), routing,
and load sharing.
• M3UA: MTP Level 3 User Adaptation Layer – Provides equivalent
primitives to MTP3 users as provided by MTP3. ISUP and/or SCCP are
unaware that expected MTP3 services are offered remotely and not
by local MTP3 layer. M3UA extends access to MTP3: layer services to
a remote IP-based application.
• SCCP: Signaling Connection Control Part – Provides a service for
transfer of messages between any two signaling points in the same
or different network.
• RNSAP: Radio Network Subsystem Application Part – Communication
protocol used on the Iur interface between RNCs and specified using

IUCS – USER/CONTROL PLANETHE PROTOCOL STACK OF IUCS INTERFACE – CONTROL/USER PLANE –
CONTAINS
• AMR: Adaptive Multirate Codec
(speech) – Offers a wide range of
data rates and is used to lower
codec rates as interference
increases on the air interface.
• TAF: Terminal Adaptation
Function (V. and X. series
terminals) – A converter protocol
to support the connection of
various kinds of TE to the MT.
• RLP: Radio Link Protocol –
Controls circuit-switched data
transmission within the GSM and

IUPS – USER/CONTROL PLANE
• The PS domain includes the
related entities for packet
transmission, the SGSN, GGSN,
and BG
• Note: The user plane payload
(IP-traffic) is transported using
AAL5. So there is no ALCAPlayer
necessary in the control plane to
set up and delete switched
virtual AAL2 ATM connections.

GN – USER/CONTROL PLANE
THE PROTOCOL STACK ON GPRS GN INTERFACE HAS NOT CHANGED SIGNIFICANTLY IN COMPARISON WITH
2.5G NETWORKS
• GTP-C: GPRS Tunneling Protocol – Control –
GTP-C messages are exchanged between
GSNs to create, update, and delete GTP
tunnels, for path management and to transfer
GSN capability information between GSN
pairs. GTP-C is also used for communication
between GSNs and the Charging Gateways.
• GTP-U: GPRS Tunneling Protocol – User –
Messages are exchanged between GSN pairs
or GSN/RNC pairs for path management and
error indication, to carry user data packets
and signaling messages.
• UDP: User Datagram Protocol – UDP is a
connectionless, host-to-host protocol that is
used on PS networks for real-time
applications.
• TCP: Transmission Control Protocol –
Provides reliable connection-oriented,
fullduplex point-to-point services.

CHANNEL
Three types of UMTS channel levels are
defined.
Physical Channels
Each Physical Channel is identified by its
frequency, spreading code, scrambling
code, and phase of the signal. Physical
Channels provide the bearers for the
different transport channels. Dedicated
Physical Channels identify a destination UE
by SF and scrambling code. One or more
Dedicated Physical Data Channels (DPDCHs)
can be configured in uplink or downlink
direction. The Dedicated Physical Control
Channel (DPCCH) is used for radio interface
related
control information only. One DPCCH always
belongs to the set of DPDCHs and is used
for
RRC messages and other signaling between
UE and network.
Transport Channels
Transport Channels are unidirectional virtual
channels, mapped onto physical channels. They
provide bearers for information exchange
between the MAC protocol and physical layer.
Only
Transport Channels of one type (e.g. Dedicated
Channels – DCHs) are mapped.
Logical Channels
Logical Channels are uni- or bidirectional and
provide bearers for information exchange 8the
MAC protocol and RLC protocol. There are two
types of Logical Channels:
 Control Channels for signaling information of
the control planes.
 Traffic Channels for user data of the user
planes.

WHAT ARE THE ADVANTAGES OF 4G OVER 3G?
• The simple answer is that a 4G network theoretically will have a higher
data transfer rate. With the appropriate amount of spectrum and good
network engineering, a Long Term Evolution (LTE)-based network has
the potential to reach 100 Mbps, while a WiMAX network can top out at
70 Mbps.
A more complex answer is that a 4G wireless network is a pure data
connection: that is, it is an end-to-end Internet Protocol connection.
This provides some real advantages, but also some disadvantages. On
the one hand, a smartphone simply becomes another data device whose
native mode is as an Internet-enabled terminal and that can be
managed as such.
• On the other hand, services such as voice require some additional
machinations to support effectively. Since voice is not intrinsically data-
centric and must be converted to data before it can be transferred,

ENODEB
• E-UTRAN Node B, also known as Evolved Node B (abbreviated
as eNodeB or eNB), is the element in E-UTRA of LTE that is the
evolution of the element Node B in UTRA of UMTS. It is the
hardware that is connected to the mobile phone network that
communicates directly wirelessly with mobile handsets (UEs),
like a base transceiver station (BTS) in GSM networks.
• Traditionally, a Node B has minimum functionality, and is
controlled by a Radio Network Controller (RNC). However, with
an eNB, there is no separate controller element. This simplifies
the architecture and allows lower response times.

MME (MOBILITY MANAGEMENT ENTITY)
• The MME is the key control-node for the LTE access-network. It is
responsible for idle mode UE (User Equipment) paging and tagging
procedure including retransmissions. It is involved in the bearer
activation/deactivation process and is also responsible for choosing
the SGW for a UE at the initial attach and at time of intra-LTE
handover involving Core Network (CN) node relocation. It is
responsible for authenticating the user (by interacting with the HSS).
The Non Access Stratum (NAS) signaling terminates at the MME and it
is also responsible for generation and allocation of temporary
identities to UEs. It checks the authorization of the UE to camp on the
service provider's Public Land Mobile Network (PLMN) and enforces
UE roaming restrictions. The MME is the termination point in the
network for ciphering/integrity protection for NAS signaling and
handles the security key management. Lawful interception of
signaling is also supported by the MME. The MME also provides the

SGW (SERVING GATEWAY)
• The SGW routes and forwards user data packets, while also
acting as the mobility anchor for the user plane during inter-
eNodeB handovers and as the anchor for mobility between LTE
and other 3GPP technologies (terminating S4 interface and
relaying the traffic between 2G/3G systems and PGW). For idle
state UEs, the SGW terminates the downlink data path and
triggers paging when downlink data arrives for the UE. It
manages and stores UE contexts, e.g. parameters of the IP
bearer service, network internal routing information. It also
performs replication of the user traffic in case of lawful
interception.

PGW (PACKET DATA NETWORK GATEWAY)
• The PDN Gateway provides connectivity from the UE to external
packet data networks by being the point of exit and entry of
traffic for the UE. A UE may have simultaneous connectivity with
more than one PGW for accessing multiple PDNs. The PGW
performs policy enforcement, packet filtering for each user,
charging support, lawful interception and packet screening.
Another key role of the PGW is to act as the anchor for mobility
between 3GPP and non-3GPP technologies such as WiMAX
and 3GPP2 (CDMA 1X and EvDO).

HSS (HOME SUBSCRIBER SERVER)
• The HSS is a central database that contains user-related and
subscription-related information. The functions of the HSS
include functionalities such as mobility management, call and
session establishment support, user authentication and access
authorization. The HSS is based on pre-Rel-4 Home Location
Register (HLR) and Authentication Center (AuC)

PCRF (POLICY AND CHARGING RULES FUNCTION)
SERVER
• The PCRF server manages the service policy and sends QoS setting
information for each user session and accounting rule information. The
PCRF Server combines functionalities for the following two UMTS nodes:
• The Policy Decision Function (PDF)
• The Charging Rules Function (CRF)
• The PDF is the network entity where the policy decisions are made. As the
IMS session is being set up, SIP signaling containing media requirements are
exchanged between the terminal and the P-CSCF. At some time in the
session establishment process, the PDF receives those requirements from
the P-CSCF and makes decisions based on network operator rules, such as:
• Allowing or rejecting the media request.
• Using new or existing PDP context for an incoming media request.
• Checking the allocation of new resources against the maximum authorized.

LTE NETWORK REFERENCE MODEL (WITH
EMPHASIS ON PCRF)

1) LTE-UU INTERFACE
• PDCP: The PDCP protocol supports efficient transport of IP packets over the radio link. It
performs header compression, Access Stratum (AS) security (ciphering and integrity
protection) and packet re-ordering/retransmission during handover.
• RLC: In the transmitting side, the RLC protocol constructs RLC PDU and provides the RLC
PDU to the MAC layer. The RLC protocol performs segmentation/concatenation of PDCP
PDUs during construction of the RLC PDU. In the receiving side, the RLC protocol performs
reassembly of the RLC PDU to reconstruct the PDCP PDU. The RLC protocol has three
operational modes (i.e. transparent mode, acknowledged mode and unacknowledged
mode), and each offers different reliability levels. It also performs packet (the RLC PDU)
re-ordering and retransmission.
• MAC: The MAC layer lies between the RLC layer and PHY layer. It is connected to the RLC
layer through logical channels, and to the PHY layer through transport channels.
Therefore, the MAC protocol supports multiplexing and de-multiplexing between logical
channels and transport channels. Higher layers use different logical channels for different
QoS metrics. The MAC protocol supports QoS by scheduling and prioritizing data from
logical channels. The eNB scheduler makes sure radio resources are dynamically allocated
to UEs and performs QoS control to ensure each bearer is allocated the negotiated QoS.

2) S1-U/S5/X2 INTERFACE
• GTP-U: GTP-U protocol1 is used to forward user IP packets over
S1-U, S5 and X2 interfaces. When a GTP tunnel is established
for data forwarding during LTE handover, an End Marker packet
is transferred as the last packet over the GTP tunnel.

1) LTE-UU INTERFACE
• NAS2: NAS protocol performs mobility management and bearer
management functions.
• RRC: RRC protocol supports the transfer of the NAS signaling. It
also performs functions required for efficient management of
the radio resources. The main functions are as follows:
• Broadcasting of system information
• Setup, reconfiguration, reestablishment and release of the RRC
connection
• Setup, modification and release of the radio bearer

1) LTE-UU INTERFACE
• X2AP: X2AP protocol supports UE mobility and SON functions
within the E-UTRAN. To support UE mobility, the X2AP protocol
provides functions such as user data forwarding, transfer of SN
status and UE context release. For SON functions, eNBs
exchange resource status information, traffic load information
and eNB configuration update information, and coordinate each
other to adjust mobility parameters using the X2AP protocol.
•

3) S1-MME INTERFACE
• S1AP: S1AP protocol supports functions such as S1 interface
management, E-RAB management, NAS signaling transport and
UE context management. It delivers the initial UE context to the
eNB to setup E-RAB(s) and manages modification or release of
the UE context thereafter.

4) S11/S5/S10 INTERFACES
• GTP-C: GTP-C protocol supports exchange of control
information for creation, modification and termination for GTP
tunnels. It creates data forwarding tunnels in case of LTE
handover.

5) S6A INTERFACE
• Diameter: Diameter protocol supports exchange of subscription
and subscriber authentication information between the HSS and
MME.

6) GX INTERFACE
Diameter: Diameter protocol
supports delivery of PCC rules
from the PCRF to the PCEF (P-GW).
7) GY INTERFACE
Diameter: Diameter protocol
supports exchange of real-time
credit control information between
the P-GW and OCS.
8) GZ INTERFACE
GTP’: GTP’ protocol supports CDR
transfer from the P-GW to the
OFCS.

S1 LAYER 1
• The main functions of S1 interface layer 1 are as following:
• Interface to physical medium;
• Frame delineation;
• Line clock extraction capability;
• Layer 1 alarms extraction and generation;
• Transmission quality control.

AIR INTERFACE PHYSICAL LAYER
• The LTE air interface physical layer offers data transport services to higher layers. The
access to these services is through the use of a transport channel via the MAC sub-layer.
The physical layer is expected to perform the following functions in order to provide the
data transport service:
• Error detection on the transport channel and indication to higher layers
• FEC encoding/decoding of the transport channel
• Hybrid ARQ soft-combining
• Rate matching of the coded transport channel to physical channels
• Mapping of the coded transport channel onto physical channels
• Power weighting of physical channels
• Modulation and demodulation of physical channels
• Frequency and time synchronisation
• Radio characteristics measurements and indication to higher layers
• Multiple Input Multiple Output (MIMO) antenna processing
• Transmit Diversity (TX diversity)
• Beamforming
• RF processing

MEDIUM ACCESS CONTROL (MAC)
• MAC protocol layer exists in UE & eNodeb, It is part of LTE air interface
control and user planes.
• The main services and functions of the MAC sublayer include:
• Mapping between logical channels and transport channels;
• Multiplexing/demultiplexing of MAC SDUs belonging to one or different
logical channels into/from transport blocks (TB) delivered to/from the
physical layer on transport channels;
• scheduling information reporting;
• Error correction through HARQ;
• Priority handling between logical channels of one UE;
• Priority handling between UEs by means of dynamic scheduling;
• Transport format selection;
• Padding.

RADIO LINK CONTROL (RLC)
• RLC protocol layer exists in UE & eNodeb, It is part of LTE air interface
control and user planes.
• The main services and functions of the RLC sublayer include:
• Transfer of upper layer PDUs;
• Error Correction through ARQ (only for AM data transfer);
• Concatenation, segmentation and reassembly of RLC SDUs (only for UM and
AM data transfer);
• Re-segmentation of RLC data PDUs (only for AM data transfer);
• In sequence delivery of upper layer PDUs (only for UM and AM data transfer);
• Duplicate detection (only for UM and AM data transfer);
• Protocol error detection and recovery;
• RLC SDU discard (only for UM and AM data transfer);
• RLC re-establishment.

PACKET DATA CONVERGENCE PROTOCOL (PDCP)
• PDCP protocol layer exists in UE & eNodeb, It is part of LTE air interface control
and user planes.
• The main services and functions of the PDCP sublayer for the user plane include:
• Header compression and decompression: ROHC only;
• Transfer of user data;
• In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure
for RLC AM;
• Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for
RLC AM;
• Retransmission of PDCP SDUs at handover for RLC AM;
• Ciphering and deciphering;
• Timer-based SDU discard in uplink.
• The main services and functions of the PDCP for the control plane include:
• Ciphering and Integrity Protection;

RADIO RESOURCE CONTROL (RRC)
• RRC protocol layer exists in UE & eNodeb, It is part of LTE air interface
control plane. The main services and functions of the RRC sublayer include:
• Broadcast of System Information related to the non-access stratum (NAS);
• Broadcast of System Information related to the access stratum (AS);
• Paging;
• Establishment, maintenance and release of an RRC connection between the
UE and E-UTRAN
• Security functions including key management;
• Establishment, configuration, maintenance and release of point to point
Radio Bearers;
• Mobility functions
• QoS management functions;
• UE measurement reporting and control of the reporting;
• NAS direct message transfer to/from NAS from/to UE.

NON-ACCESS-STRATUM (NAS) PROTOCOL
• The non-access stratum (NAS) is highest stratum of the control plane
between UE and MME at the radio interface. Main functions of the
protocols that are part of the NAS are the support of mobility of the
user equipment (UE) and the support of session management
procedures to establish and maintain IP connectivity between the UE
and a packet data network gateway (PDN GW).
• NAS control protocol performs followings:
• EPS bearer management;
• Authentication;
• ECM-IDLE mobility handling;
• Paging origination in ECM-IDLE;
• Security control.

S1 APPLICATION PROTOCOL (S1AP)
• S1AP provides the signalling service between E-UTRAN and the evolved packet core (EPC) and has
following functions:
• E-RAB management function
• Initial Context Transfer function
• UE Capability Info Indication function
• Mobility Functions
• S1 interface management functions
• NAS Signalling transport function
• S1 UE context Release function
• UE Context Modification function
• Status Transfer
• Trace function
• Location Reporting
• S1 CDMA2000 Tunneling function
• Warning message transmission function
• RAN Information Management (RIM) function
• Configuration Transfer function

S1 SIGNALLING TRANSPORT
• S1 signalling bearer provides the following functions:
• Provision of reliable transfer of S1-AP message over S1-MME interface.
• Provision of networking and routeing function
• Provision of redundancy in the signalling network
• Support for flow control and congestion control
• L2 - Data link layer
• Support of any suitable data link layer protocol, e.g. PPP, Ethernet
• IP layer
• The eNB and MME support IPv6 and/or IPv4
• The IP layer of S1-MME only supports point-to-point transmission for delivering S1-AP message.
• The eNB and MME support the Diffserv Code Point marking
• Transport layer
• SCTP is supported as the transport layer of S1-MME signalling bearer.
• SCTP refers to the Stream Control Transmission Protocol developed by the Sigtran working group of
the IETF for the purpose of transporting various signalling protocols over IP network.
• There is only one SCTP association established between one MME and eNB pair.
• The eNB establishes the SCTP association. The SCTP Destination Port number value assigned by IANA
to be used for S1AP is 36412.

X2 APPLICATION PROTOCOL (X2AP)
• The X2AP protocol is used to handle the UE mobility within E-
UTRAN and provides the following functions:
• Mobility Management
• Load Management
• Reporting of General Error Situations
• Resetting the X2
• Setting up the X2
• eNB Configuration Update

X2 LAYER 1
• The main functions of X2 interface layer 1 are as following:
• Interface to physical medium;
• Frame delineation;
• Line clock extraction capability;
• Layer 1 alarms extraction and generation;
• Transmission quality control.

X2 SIGNALLING TRANSPORT
• X2 signalling bearer provides the following functions:
• Provision of reliable transfer of X2-AP message over X2 interface.
• Provision of networking and routeing function
• Provision of redundancy in the signalling network
• Support for flow control and congestion control
• L2 - Data link layer
• Support of any suitable data link layer protocol, e.g. PPP, Ethernet
• IP layer
• The eNB supports IPv6 and/or IPv4
• The IP layer of eNB-eNB only supports point-to-point transmission for delivering X2-AP message.
• The eNB supports the Diffserv Code Point marking
• Transport layer
• SCTP is supported as the transport layer of eNB-eNB signalling bearer.
• SCTP refers to the Stream Control Transmission Protocol developed by the Sigtran working group of the IETF for the
purpose of transporting various signalling protocols over IP network.
• There is only one SCTP association established between eNB pairs.
• The eNB establishes the SCTP association. The SCTP Destination Port number value assigned by IANA to be used for
X2AP is 36422.

GPRS TUNNELLING PROTOCOL USER PLANE (GTP-
U)
• GTP-U protocol is used over S1-U, X2, S4, S5 and S8 interfaces
of the Evolved Packet System (EPS). GTP-U Tunnels are used to
carry encapsulated T-PDUs and signalling messages between a
given pair of GTP-U Tunnel Endpoints. The Tunnel Endpoint ID
(TEID) which is present in the GTP header indicates which
tunnel a particular T-PDU belongs to.
• The transport bearer is identified by the GTP-U TEID and the IP
address (source TEID, destination TEID, source IP address,
destination IP address).

GTP-U TRANSPORT
• The transport layer for data streams over S1, X2, S4, S5 and
S8 is an IP based Transport. The GTP-U protocol over UDP
over IP is supported as the transport for data streams on the
user data interfaces.
• Any data link protocol that fulfils the requirements toward the
upper layer may be used.
• UDP/IP
• The UDP port number for GTP-U is as defined in 3GPP TS
29.281.
• The eNB and the EPC support fragmentation and assembly of
GTP packets at the IP layer.
• The eNB and the EPC support IPv6 and/or IPv4.

We talk about interfaces in 4g network in this link:
• Interfaces

5G DESCRIPTION:
• 5G envisions to design a real wireless world, that is free from
obstacles of the earlier generations.
• 5G aims to design a Multi-Bandwidth Data Path by integrating the
current and
• The 5G technology aims to distributes internet access to nodes
across the world with almost seamless speed.future networks for new
network architecture of 5G real wireless world.
• The high quality services of 5G technology is based on Policy to avoid
error.
• 5G technology would provide large broadcasting of data in
Gigabytes.
• 5G will promote concept of Super Core, where all the network
operators will be connected one single core and have one single

SO WE LOOKING FOR THIS QUESTION WHY
SHOULD WE GO TO 5G NETWORK?

HOW FAST IS 5G?
• I think we found our answer

LATENCY & JITTER
• Latencyis generally defined as the time it takes for a source to
send a packet of data to a receiver. In simple terms, half of Ping
time. This is also referred to as one way latency.
• Sometimes the term Round trip latencyor round trip time (RTT)
is also used to define latency. This is the same as ping time.
• Jitteris defined as the variation in the delay (or latency) of
received packets. It is also referred to as ‘delay jitter’.

Recommendation Q.713
SIGNALLING CONNECTION CONTROL PART FORMATS AND CODES
(revised in 1996)
1 General
This Recommendation specifies the SCCP messages formats and codes for the support of connection-oriented services, connectionless services and the management of SCCP.
The SCCP messages are passed between SCCP and MTP across the MTP-SAP by means of the user data parameter of the MTP-TRANSFER request or indication primitives as appropriate (see Table 1/Q.701).
NOTE – The MTP-TRANSFER primitive, in addition to the user data parameter, contains four parameters with the contents as follows (see Table 1/Q.701):
• the contents of the OPC consisting of information equivalent to 14 bits, to be conveyed in the standard routing label of the MTP;
• the contents of the DPC consisting of information equivalent to 14 bits, to be conveyed in the standard routing label of the MTP;
• the contents of the SLS consisting of information equivalent to 4 bits. If the MTP service "in-sequence delivery" of SDUs is a requirement, SCCP shall use the same SLS value for all
SDUs with the same sequence control and called address parameters;
• information equivalent to the contents of the SIO. For SCCP, the encoding for the service indicator is 0011 binary (see 14.2.1/Q.704).
A SCCP message consists of the following parts (see Figure 1):
–
–
–
–
the message type code;
the mandatory fixed
part;
the mandatory variable part;
the optional part, which may contain fixed length and variable length
fields.
The description of the various parts is contained in the following subclauses. SCCP management
messages and codes are provided in clause 5.
MTP routing label
Message type code
Mandatory fixed part
Mandatory variable part
Optional part



 SCCP
Message







 SIF
Figure 1/Q.713 – General
layout

1. Message type code
The message type code consists of a one octet field and is mandatory for all messages. The message type code uniquely defines the function and format of each
SCCP message. The allocation of message type codes, with reference to the appropriate descriptive subclause of this Recommendation is summarized in Table
1. Table 1 also contains an indication of the applicability of the various message types to the relevant classes of protocol.
2. Formatting principles
Each message consists of a number of parameters listed and described in clause 3. Each parameter has a "name" that can be represented by a single octet (see
clause 3), and is present in optional parameters. The length of a parameter may be fixed or variable, and a "length indicator" of one octet for each parameter
may be included as described below. The length indicator of the long data parameter shall be two octets, with the less significant octet preceding the
transmission of the more significant octet.
The detailed format is uniquely defined for each message type as described in clause 4. A general SCCP message format is shown in Figure 2.

8 7 6 5 4 3 2
T1178720-96
Order of octet
1 transmission
Mandatory
fixed part
Mandatory
variable part
Optional part
Message type code
Mandatory parameterA
Mandatory parameter F
Pointer to parameter M
Pointer to parameter P
Pointer to start of optional part
Length indicator of parameterM
ParameterM
Length indicator of parameter P
Parameter P
Parameter name = X
Length indicator of parameterX
Parameter X
Parameter name =Z
Length indicator of parameterZ
Parameter Z
End of optional parameters
Figure 2/Q.713 – General SCCP message format
3. Mandatory fixed part
Those parameters that are mandatory and of fixed length for a particular message type will be contained in the "mandatory fixed
part". The position, length and order of the parameters is uniquely defined by the message type. Thus the names of the parameters
and the length indicators are not included in the message.
4. Mandatory variable part
Mandatory parameters of variable length will be included in the mandatory variable part. The name of each parameter and the
order in which the pointers are sent is implicit in the message type. Parameter names are, therefore, not included in the message.
A pointer is used to indicate the beginning of each parameter. Because of this, parameters may be sent in an order different from
that of the pointers. Each pointer is encoded as a single octet or two octets in the case of LUDT and LUDTS. In the case of the
two-octet pointer, the less significant octet shall be transmitted before the more significant octet. The details of how pointers are
encoded is found in 2.3. The number of parameters, and thus the number of pointers, is uniquely defined by the message type.

A pointer is also included to indicate the beginning of the optional part. If the message
type indicates that no optional part is allowed, then this pointer will not be present. If
the message type indicates that an optional part is possible, but there is no optional
part included in this particular message, then a pointer field containing all zeros will
be used.
All the pointers are sent consecutively at the beginning of the mandatory variable part.
Each parameter contains the parameter length indicator followed by the contents of
the parameter.
All the pointers indicating the beginning of each mandatory variable parameter and the
beginning of the optional part shall ensure that at the originating node the parameters
are contiguous; and "gaps" shall not be left in between parameters in generating
messages. Treatment of "gaps" at the receiving side is specified in 1.1.4.5/Q.714. Gaps
should not be generated between the last pointer and first mandatory variable
parameter. No extraneous octets should be added after the last parameter. All the
above cases will not cause a protocol error.
5. Optional part
The optional part consists of a contiguous block of parameters that may or may not
occur in any particular message type. The optional part may start after the pointer or
after the mandatory variable part. Both fixed length and variable length parameters
may be included. Optional parameters may be transmitted in any order. Each optional
parameter will include the parameter name (one octet) and the length indicator (one
octet) followed by the parameter contents.
6. End of optional parameters octet
After all optional parameters have been sent, an end of optional parameters octet
containing all zeros will be transmitted. This octet is included only if optional
parameters are present in the message. The end of optional parameters octet should
not be used to detect the end of messages.
7. Order of transmission
Since all the parameters consist of an integral number of octets, the formats are
presented as a stack of octets. The first octet transmitted is the one shown at the top of
the stack and the last is the one at the bottom (see Figure 2).
8. Coding of spare bits
According to the general rules defined in Recommendations Q.700 and Q.1400, spare
bits are coded
0 unless indicated otherwise at the originating nodes. Handling of spare fields is
specified in 1.1.4.4/Q.714.
1.9 National message types and parameters
If message type codes and parameter codes are required for national uses, it is
suggested that the codes be selected from the highest code downwards, that is starting
at code 11111110. Code 11111111 is reserved for future use.

1.10 International message types and parameters
Message type codes and parameter codes are required for international use. These codes are
selected from the lowest code values upwards, i.e. starting at 00000000. Note that the special
codes applicable for international use are specified in each relevant subclause.
2 Coding of the general
parts
2.1 Coding of the message type
The coding of the message is shown in Table 1.
Table 1/Q.713 – SCCP message
types
Message type
Classes
Reference
Mes
sage
type
code
0 1 2 3
CR Connection request X X 4.2 00000001
CC Connection confirm X X 4.3 00000010
CREF Connection refused X X 4.4 00000011
RLSD Released X X 4.5 00000100
RLC Release complete X X 4.6 00000101
DT1 Data form 1 X 4.7 00000110
DT2 Data form 2 X 4.8 00000111
AK Data acknowledgement X 4.9 00001000
UDT Unitdata X X 4.10 00001001
UDTS Unitdata service X1
X1 4.11 00001010
ED Expedited data X 4.12 00001011
EA Expedited data acknowledgement X 4.13 00001100
RSR Reset request X 4.14 00001101
RSC Reset confirm X 4.15 00001110
ERR Protocol data unit error X X 4.16 00001111
IT Inactivity test X X 4.17 00010000
XUDT Extended unitdata X X 4.18 00010001
XUDTS Extended unitdata service X1
X1 4.19 00010010
LUDT Long unitdata X X 4.20 00010011
LUDTS Long unitdata service X1
X1 4.21 00010100
X = Type of message of this protocol class.
X1
= Type of protocol class is indeterminate (absence of protocol class parameter).
2.2 Coding of the length indicator
The length indicator field is binary coded to indicate the number of octets in the parameter content
field. The length indicator does not include the parameter name octet or the length indicator octet.

2.3 Coding of the pointers
The pointer value (in binary) gives the number of octets between the most
significant octet of pointer itself (included) and the first octet (not included)
of the parameter associated with that pointer2 as shown in the following
diagram.
T1178730-96
Pointer value
Pointer
LSB
MSB
P
ointer
First
octet
of
param
eter
The pointer value all zeros is used to indicate that, in the case of optional
parameters, no optional parameter is present.
3 SCCP parameters
The parameter name codes are given in Table 2 with reference to the
subclauses in which they are described.

Table 2/Q.713 – SCCP parameter name codes
Parameter name Reference Parameter name
code
8765
4321
End of optional parameters 3.1 00000000
Destination local reference 3.2 00000001
Source local reference 3.3 00000010
Called party address 3.4 00000011
Calling party address 3.5 00000100
Protocol class 3.6 00000101
Segmenting/reassembling 3.7 00000110
Receive sequence number 3.8 00000111
Sequencing/segmenting 3.9 00001000
Credit 3.10 00001001
Release cause 3.11 00001010
Return cause 3.12 00001011
Reset cause 3.13 00001100
Error cause 3.14 00001101
Refusal cause 3.15 00001110
Data 3.16 00001111
Segmentation 3.17 00010000
Hop counter 3.18 00010001
Importance 3.19 00010010
Long data 3.20 00010011
1. End of optional parameters
The "end of optional parameters" parameter field consists of a single octet containing all zeros.
2. Destination local reference
The "destination local reference" parameter field is a three-octet field containing a reference number
which, in outgoing messages, has been allocated to the connection section by the remote node.
The coding "all ones" is reserved for future use.
3. Source local reference
The "source local reference" parameter field is a three-octet field containing a reference number
which is generated and used by the local node to identify the connection section after the connection
section is set up.
The coding "all ones" is reserved for future use.

8 7 6 5 4 3 2 1
Address indicator
Address
3.4 Called party address
The "called party address" is a variable length parameter. Its structure is shown in Figure3.
octet 1
octet 2
.
.
.
octet n
Figure 3/Q.713 – Called/calling party address
3.4.1 Address indicator
The "address indicator" indicates the type of address information contained in the address field (see
Figure 4). The address consists of one or any combination of the following elements:
–
–
–
signalling point code;
global title (for instance, dialled digits);
subsystem number.
8 7 6 5 4 3 2 1
Reservedfor national use Routing indicator Global title indicator SSN indicator Pointcode indicator
Figure 4/Q.713 – Address indicator encoding
A "1" in bit 1 indicates that the address contains a signalling point code.
A "1" in bit 2 indicates that the address contains a subsystem number.
Bits 3-6 of the address indicator octet contain the Global Title Indicator (GTI), which is encoded as
follows:
Bits 6 5 4 3
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
no global title included
global title includes nature of address indicator only
global title includes translation type only
global title includes translation type, numbering plan and encoding scheme
global title includes translation type, numbering plan, encoding scheme and nature
of address indicator



spare international



spare national
0 1 0 1
to
0 1 1 1
1 0 0 0
to
1 1 1 0
1 1 1 1 reserved for extension.

Bit 7 of the address indicator octet contains routing information identifying which
address element shall be used for routing, and is encoded as follows:
Bit 7
1 Route on SSN
0 Route on GT.
Bit 8 of the address indicator octet is reserved for national use and is always set to zero
on an international network.
3.4.2 Address
The various elements, when provided, occur in the order: point code, subsystem
number, global title, as shown in Figure 5.
It is suggested that the called party address contains a subsystem number. This serves
to simplify message reformatting following global title translation. The subsystem
number shall be encoded "00000000" when the subsystem number is not known, e.g.
before translation.
8 7 6 5 4 3 2 1
Signalling point code
Subsystem number
Global title
Figure 5/Q.713 – Ordering of address elements
3.4.2.1 Signalling point code
The signalling point code, when provided, is represented by two octets. Bits 7 and 8 in
the second octet are set to zero (see Figure 6).
8 7 6 5 4 3 2 1
LSB
0 0 MSB
Figure 6/Q.713 – Signalling point code encoding
3.4.2.2 Subsystem number
The Subsystem Number (SSN) identifies an SCCP user function and, when provided,
consists of one octet coded as follows:
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 0 0 SSN not known/not used
0 0 0 0 0 0 0 1 SCCP management
0 0 0 0 0 0 1 0 reserved for ITU-T allocation
0 0 0 0 0 0 1 1 ISDN user part
0 0 0 0 0 1 0 0 OMAP (Operation, Maintenance and Administration
Part)
0 0 0 0 0 1 0 1 MAP (Mobile Application Part)
0 0 0 0 0 1 1 0 HLR (Home Location Register)
0 0 0 0 0 1 1 1 VLR (Visitor Location Register)
0 0 0 0 1 0 0 0 MSC (Mobile Switching Centre)
0 0 0 0 1 0 0 1 EIC (Equipment Identifier Centre)

Bits 8 7 6 5 4 3 2 1
0 0 0 0 1 0 1 0 AUC (Authentication Centre)
0 0 0 0 1 0 1 1 ISDN supplementary services
0 0 0 0 1 1 0 0 reserved for international use
0 0 0 0 1 1 0 1 broadband ISDN edge-to-edgeapplications
0 0 0 0 1 1 1 0 TC test responder



reserved for international use



reserved for national networks
0 0 0 0 1 1 1 1
to
0 0 0 1 1 1 1 1
0 0 1 0 0 0 0 0
to
1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1 reserved for expansion of national and international SSN.
numbers should be assigned in descending order starting with
Network specific subsystem
"11111110".
3.4.2.3 Global title
The format of the Global Title (GT) is of variable length. Figures 7, 9, 10 and 11 show four possible
formats for global title.
3.4.2.3.1 Global title indicator = 0001
Figure 7 shows the format of the global title, if the global title indicator equals "0001".
8 7 6 5 4 3 2 1
O/
E
Nature of address indicator Octet 1
Global title address information Octet 2 and further
Figure 7/Q.713 – Global title format for indicator 0001
Bits 1 to 7 of octet 1 contain the Nature of Address Indicator (NAI) and are coded as follows:
unknown
subscriber number
reserved for national use
national significant number
international number
Bits 7 6 5 4 3 2 1
0 0 0 0 0 0 0
0 0 0 0 0 0 1
0 0 0 0 0 1 0
0 0 0 0 0 1 1
0 0 0 0 1 0 0
0 0 0 0 1 0 1
to
1 1 1 1 1 1 1



spare
Bit 8 of octet 1 contains the odd/even indicator and is coded as follows:
Bit 8
0 even number of addresssignals
1 odd number of addresssignals.

The octets 2 and further contain a number of address signals and possibly a filler as shown in Figure
8.
8 7 6 5 4 3 2 1
2nd address signal 1st address signal Octet 2
4th address signal 3rd address signal Octet 3
. . .
filler (if necessary) nth address signal Octet m a)
a)
m depends on the restriction posed by the numbering plan in its defining
Recommendation.
Figure 8/Q.713 – Global title address information
(if encoding scheme is BCD)
Each address signal is coded as follows:
0000 digit 0
0001 digit 1
0010 digit 2
0011 digit 3
0100 digit 4
0101 digit 5
0110 digit 6
0111 digit 7
1000 digit 8
1001 digit 9
1010 spare
1011 code
11
1100 code
12
1101 spare
1110 spare
1111 ST
In case of an odd number of address signals, a filler code 0000 is inserted after the last address signal.
The Translation Type (TT) is a one-octet field that is used to direct the message to the appropriate translator.
8 7 6 5 4 3 2 1
Translation type Octet 1
This octet will be coded "00000000" when not used. Translation types for internetwork services will
be assigned in ascending order starting with "00000001". Translation types for network specific

services will be assigned in descending order starting with "11111110". The code "11111111" is
reserved for expansion.
Global title with GTI = 0010 is for national use only and is not used on the international interface.
The allocation of the translation types for GTI = 0010 is a national matter.
In the case of this global title format (0010), the translation type may also imply the encoding
scheme, used to encode the address information, and the numbering plan.
8 7 6 5 4 3 2 1
Numbering plan Encoding scheme Octet 2
The coding and definition of the translation type for this global title format (0011) is for further
study.
The Numbering Plan (NP) is encoded as follows:
unknown
ISDN/telephony numbering plan (Recommendations E.163 and E.164)
generic numbering plan
data numbering plan (Recommendation X.121)
telex numbering plan (Recommendation F.69)
maritime mobile numbering plan (Recommendations E.210, E.211)
land mobile numbering plan (Recommendation E.212)
ISDN/mobile numbering plan (Recommendation E.214)



spare
Bits 8 7 6 5
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
1 0 0 0
to
1 1 0 1
1 1 1 0
1 1 1 1
private network or network-specific numbering plan
reserved.
The Encoding Scheme (ES) is encoded as follows:
unknown
BCD, odd number of digits
BCD, even number of digits
national specific



spare
Bits 4 3 2 1
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
to
1 1 1 0
1 1 1 1 reserved.

If the encoding scheme is binary coded decimal, the global title address information, starting from
octet 3, is encoded as shown in Figure 8.
8 7 6 5 4 3 2 1
Numbering plan Encoding scheme Octet 2
0 Nature of address indicator Octet 3
This global title format (0100) is used for international network applications. In this case, the
"translation type" along with the allowable combination of its "numbering plan", "nature of address
indicator", and "encoding scheme" is specified in Annex B.
The fields "numbering plan" and "encoding scheme" are as described in 3.4.2.3.3. The field "nature
of address indicator" is as described in 3.4.2.3.1.
If the encoding scheme is binary coded decimal, the global title address information, starting from
octet 4, is encoded as shown in Figure 8.
The ranges of the translation types to be allocated for global title with GTI = 0100 are shown as
follows:
unknown



international services



spare



national network specific
Bits 8 7 6 5 4 3 2 1 Decimal Value
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 1 1
to to
0 0 1 1 1 1 1 1 63
0 1 0 0 0 0 0 0 64
to to
0 1 1 1 1 1 1 1 127
1 0 0 0 0 0 0 0 128
to to
1 1 1 1 1 1 1 0 254
1 1 1 1 1 1 1 1 255 reserved for expansion
3.5 Calling party address
The "calling party address" is a variable length parameter. Its structure is the same as the "called party
address".
For compatibility reasons with earlier versions, an SCCP should be able to receive and/or transfer a
(X)UDT message in which the calling party address parameter only consists of the address indicator
octet, where bits 1 to 7 are coded all zeros.
However, it is recommended that the origination point does not code the address indicator octet
where bits 1 to 7 are coded all zeros. It is recommended that further information (GT and/or SSN)
should be provided.

3.6 Protocol class
The "protocol class" parameter field is a one-octet parameter and is structured as follows:
Bits 1-4 indicating protocol class are coded as follows:
4321
0000 class0
0001 class1
0010 class2
0011 class3When bits 1-4 are coded to indicate a connection-oriented-protocol class (class 2, class 3), bits 5-8
are spare.
When bits 1-4 are coded to indicate a connectionless protocol class (class 0, class 1), bits 5-8 are used
to specify message handling as follows:
no special options



spare
return message on error
Bits 8 7 6 5
0 0 0 0
0 0 0 1
to
0 1 1 1
1 0 0 0
1 0 0 1
to
1 1 1 1



spare
3.7 Segmenting/reassembling
The "segmenting/reassembling" parameter field is a one octet field and is structured as follows:
8 7 6 5 4 3 2 1
Spare M
Bits 8-2 are spare.
Bit 1 is used for the more data indication and is coded as follows:
–
–
0 = no more data;
1 = more data.
3.8 Receive sequence number
The "receive sequence number" parameter field is a one octet field and is structured as follows:
8 7 6 5 4 3 2 1
P(R) Spare
Bits 8-2 contain the receive sequence number P(R) used to indicate the sequence number of the next
expected message. P(R) is binary coded and bit 2 is the LSB.
Bit 1 is spare.

8 7 6 5 4 3 2 1
P(S) Spare
P(R) M
3.9 Sequencing/segmenting
The sequencing/segmenting parameter field consists of two octets and is structured as follows:
Octet 1
Octet 2
Bits 8-2 of octet 1 are used for indicating the send sequence number P(S). P(S) is binary coded and
bit 2 is the LSB.
Bit 1 of octet 1 is spare.
Bits 8-2 of octet 2 are used for indicating the receive sequence number P(R). P(R) is binary coded
and bit 2 is the LSB.
Bit 1 of octet 2 is used for the more data indication and is coded as follows:
–
–
0 = no more data;
1 = more data.
The sequencing/segmenting parameter field is used exclusively in protocol class 3.
10. Credit
The "credit" parameter field is a one-octet field used in the protocol class 3 which includes flow
control functions. It contains the window size value coded in pure binary.
11. Release cause
The release cause parameter field is a one-octet field containing the reason for the release of the
connection.
The coding of the release cause field is as follows:
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 0 0 end user originated
0 0 0 0 0 0 0 1 end user congestion
0 0 0 0 0 0 1 0 end user failure
0 0 0 0 0 0 1 1 SCCP user originated
0 0 0 0 0 1 0 0 remote procedure error
0 0 0 0 0 1 0 1 inconsistent connection data
0 0 0 0 0 1 1 0 access failure
0 0 0 0 0 1 1 1 access congestion
0 0 0 0 1 0 0 0 subsystem failure
0 0 0 0 1 0 0 1 subsystem congestion
0 0 0 0 1 0 1 0 MTP failure
0 0 0 0 1 0 1 1 network congestion
0 0 0 0 1 1 0 0 expiration of reset timer
0 0 0 0 1 1 0 1 expiration of receive inactivity
timer
0 0 0 0 1 1 1 0 reserved
0 0 0 0 1 1 1 1 unqualified
0 0 0 1 0 0 0 0 SCCP failure0 0 0 1 0 0 0 1
to
1 1 1 1 1 1 1 1



spare

3.12 Return cause
In the unitdata service or extended unitdata service or long unitdata service message, the "return
cause" parameter field is a one octet field containing the reason for message return. Bits 1-8 are coded
as follows:
to
1 1 1 1 1 1 1 1
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 0 0 no translation for an address of such nature
0 0 0 0 0 0 0 1 no translation for this specific address
0 0 0 0 0 1 0 0 unequipped user
0 0 0 0 0 1 0 1 MTP failure
0 0 0 0 1 0 0 0 error in message transport (Note)
0 0 0 0 1 0 0 1 error in local processing (Note)
0 0 0 0 1 0 1 0 destination cannot perform reassembly
(Note)
0 0 0 0 1 0 1 1 SCCP failure
0 0 0 0 1 1 0 0 hop counter violation
0 0 0 0 1 1 0 1 segmentation not supported
0 0 0 0 1 1 1 0 segmentation failure
0 0 0 0 1 1 1 1 


spare
NOTE – Only applicable to XUDT(S) message.
3.13 Reset cause
The "reset cause" parameter field is a one octet field containing the reason
for the resetting of the connection.
The coding of the reset cause field is as follows:
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 1 0 message out of order – incorrect P(S)
0 0 0 0 0 0 1 1 message out of order – incorrect P(R)
0 0 0 0 0 1 0 0 remote procedure error – message out of window
0 0 0 0 0 1 0 1 remote procedure error – incorrect P(S) after
(re)initialization
0 0 0 0 0 1 1 0 remote procedure error – general
0 0 0 0 0 1 1 1 remote end user operational
0 0 0 0 1 0 0 0 network operational
0 0 0 0 1 0 0 1 access operational
0 0 0 0 1 0 1 1 reserved
0 0 0 0 1 1 0 0 unqualified0 0 0 0 1 1 0 1
to
1 1 1 1 1 1 1 1



spare

3.14 Error cause
The "error cause" parameter field is a one octet field containing the indication of the exact protocol
error.
The coding of the error cause field is as follows:
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 0 0 Local Reference Number (LRN) mismatch – unassigned
destination LRN
0 0 0 0 0 0 0 1 Local Reference Number (LRN) mismatch – inconsistent source
LRN
0 0 0 0 0 0 1 0 point code mismatch3
0 0 0 0 0 0 1 1 service class mismatch
0 0 0 0 0 1 0 1
to
1 1 1 1 1 1 1 1



spare
3.15 Refusal cause
The refusal cause parameter field is a one octet field containing the reason for the refusal of the
connection.
The coding of the refusal cause field is as follows:
Bits 8 7 6 5 4 3 2 1
0 0 0 0 0 0 0 1 end user congestion
0 0 0 0 0 0 1 0 end user failure
0 0 0 0 0 1 0 0 destination address unknown
0 0 0 0 0 1 0 1 destination inaccessible
0 0 0 0 0 1 1 0 network resource – QOS not available/non-
transient
0 0 0 0 0 1 1 1 network resource – QOS not available/transient
0 0 0 0 1 0 0 0 access failure
0 0 0 0 1 0 0 1 access congestion
0 0 0 0 1 1 0 0 expiration of the connection establishment
timer
0 0 0 0 1 1 0 1 incompatible user data
0 0 0 0 1 1 1 0 reserved
0 0 0 1 0 0 0 0 hop counter violation
0 0 0 1 0 0 0 1 SCCP failure
0 0 0 1 0 0 1 0 no translation for an address of such nature
0 0 0 1 0 0 1 1 unequipped user
0 0 0 1 0 1 0 0
to
1 1 1 1 1 1 1 1



spare

16. Data
The "data" parameter field is a variable length field containing less than or equal to 255 octets of
SCCP-user data to be transferred transparently between the SCCP user functions.
17. Segmentation
8 7 6 5 4 3 2 1
F C Spare Remaining segment Octet 1
Segmentation local reference
Octet2
Octet3
Octet4
Bit 8 of octet 1 is used for first segment indication and is coded as follows:
–
–
0: in all segments but the first;
1: first segment.
Bit 7 of octet 1 is used to keep in the message in sequence delivery option required by the SCCP user
and is coded as follows:
–
–
0: Class 0 selected;
1: Class 1 selected.
Bits 6 and 5 in octet 1 are spare bits.
Bits 4-1 of octet 1 are used to indicate the number of remaining segments. The values 0000 to 1111
are possible; the value 0000 indicates the last segment.
3.18 Hop counter
8 7 6 5 4 3 2 1
Hop counter
The hop counter parameter consists of one octet. The value of the hop counter, which is decremented
on each global title translation, should be in range 15 to 1.
3.19 Importance
The "importance" parameter field is a one-octet field and is structured as follows:
8 7 6 5 4 3 2 1
Spare Importance
Bits 1-3 are binary coded to indicate the importance of the messages. The values are between 0 and 7,
where the value of 0 indicates the least important and the value of 7 indicates the most important.
Bits 4-8 are spare bits.
The importance values may be subject to improvement pending further analysis of the impact of the
SCCP congestion control procedures in different network scenarios and based on the results of
operational experiences.

3.20 Long data
The "long data" parameter field is a variable length field containing SCCP-user data up to 3952 octets
to be transferred transparently between the SCCP user functions. The "long data" parameter has a
two-octet "length indicator" field.
4 SCCP messages and codes
4.1 General
4.1.1 In the following subclauses, the format and coding of the SCCP messages is specified.
For each message a list of the relevant parameters is given in a tabular form.
–
4.1.2 For each parameter the table also includes:
– a reference to the subclause where the formatting and coding of the parameter content is
specified;
the type of the parameter. The following types are used in thetables:
F = mandatory fixed length parameter;
V = mandatory variable length parameter;
O = optional parameter of fixed or variable length;
– the length of the parameter. The value in the table includes:
– for type F parameters the length, in octets, of the parameter content;
– for type V parameters the length, in octets, of the length indicator and of the parameter
content; (The minimum and the maximum length are indicated.)
– for type O parameters the length, in octets, of the parameter name, length indicator and
parameter content. (For variable length parameters the minimum and maximum length is
indicated.)
4.1.3
4.1.4
For each message the number of pointers included is also specified.
For each message type, type F parameters and the pointers for the type V parameters must be
sent in the order specified in the following tables. The pointer to the optional parameter block occurs
after all pointers to variable parameters.
4.2 Connection request (CR)
The CR message contains:
–
–
two pointers;
the parameters indicated in Table 3.

Table 3/Q.713 – Message type: Connection request
Parameter Reference Type (F V O) Le
ng
th
(oc
tet
s)
Message type code 2.1 F 1
Source local reference 3.3 F 3
Protocol class 3.6 F 1
Called party address 3.4 V 3 minimum
Credit 3.10 O 3
Calling party address 3.5 O 4 minimum
Data 3.16 O 3-130
Hop counter 3.18 O 3
Importance 3.19 O 3
End of optional parameters 3.1 O 1
4.3 Connection confirm (CC)
The CC message contains:
–
–
one pointer;
the parameters indicated in Table4.
Table 4/Q.713 – Message type: Connection confirm
ng
th
(oc
tet
s)
Message type 2.1 F 1
Destination local reference 3.2 F 3
Credit 3.10 O 3
Called party address 3.4 O 4 minimum
Data 3.16 O 3-130
Importance 3.19 O 3
End of optional parameter 3.1 O 1
4.4 Connection refused (CREF)
The CREF message contains:
–
–
one pointer;

Table 5/Q.713 – Message type: Connection refused
ng
th
(oc
tet
s)
Refusal cause 3.15 F 1
Called party address 3.4 O 4 minimum
Data 3.16 O 3-130
Importance 3.19 O 3
4.5 Released (RLSD)
The RLSD message contains:
–
–
one pointer;
Table 6/Q.713 – Message type: Released
ng
th
(oc
tet
s)
Release cause 3.11 F 1
Data 3.16 O 3-130
Importance 3.19 O 3
4.6 Release complete (RLC)
The RLC message contains:
–
–
no pointers;
Table 7/Q.713 – Message type: Release complete
Parameter Reference Type (F V O) Length
(octets)

4.7 Data form 1 (DT1)
The DT1 message contains:
–
–
one pointer;
Table 8/Q.713 – Message type: Data form 1
Parameter Reference Type (F V O) Length
(octets)
Segmenting/reassembling 3.7 F 1
Data 3.16 V 2-256
4.8 Data form 2 (DT2)
The DT2 message contains:
–
–
one pointer;
Table 9/Q.713 – Message type: Data form 2
Parameter Reference Type (F V O) Length (octets)
Sequencing/segmenting 3.9 F 2
Data 3.16 V 2-256
4.9 Data acknowledgement(AK)
The AK message contains:
–
–
no pointers;
Table 10/Q.713 – Message type: Data acknowledgement
Receive sequence number 3.8 F 1
Credit 3.10 F 1

4.10 Unitdata (UDT)
The UDT message contains:
–
–
three pointers;
Table 11/Q.713 – Message type: Unitdata
Calling party address 3.5 V 3 minimumb)
Data 3.16 V 2-Xa)
a)
Due to the ongoing studies on the SCCP called and calling party address, the maximum length of this parameter needs further study. It is also
noted that the transfer of up to 255 octets of user data is allowed when the SCCP called and calling party address do not include global
title.
b)
The minimum length = 2 might apply in the special case of AI = X0000000 described in 3.5.
4.11 Unitdata service (UDTS)
The UDTS message contains:
–
–
three pointers;
Table 12/Q.713 – Message type: Unitdata service
Parameter Reference Type (F V O)
Length
(octets)
Return cause 3.12 F 1
Calling party address 3.5 V 3 minimum
Data 3.16 V 2-Xa)
a)
See a)
in Table 11.
4.12 Expedited data (ED)
The ED message contains:
–
–
one pointer;

Table 13/Q.713 – Message type: Expedited data
Data 3.16 V 2-33
4.13 Expedited data acknowledgement (EA)
The EA message contains:
–
–
no pointers;
Table 14/Q.713 – Message type: Expedited data acknowledgement
4.14 Reset request (RSR)
The RSR message contains:
–
–
one pointer (this allows for inclusion of optional parameters in the future);
Table 15/Q.713 – Message type: Reset request
Reset cause 3.13 F 1
4.15 Reset confirmation (RSC)
The RSC message contains:
–
–
no pointers;

Table 16/Q.713 – Message type: Reset confirmation
4.16 Protocol data unit error (ERR)
The ERR message contains:
–
–
one pointer (this allows for inclusion of optional parameters in the future);
Table 17/Q.713 – Message type: Protocol data unit error
Error cause 3.14 F 1
4.17 Inactivity test (IT)
The IT message contains:
–
–
no pointers;
Table 18/Q.713 – Message type: Inactivity test
Length (octets)
Sequencing/segmentinga)
3.9 F 2
Credita)
3.10 F 1
a)
Information in these parameter fields reflect those values sent in the last data form 2 or data acknowledgement message. They are ignored if the protocol class parameter indicates
class 2.
4.18 Extended unitdata (XUDT)
The XUDT message contains:
–
–
four pointers;

Table 19/Q.713 – Message type: Extended unitdata
Hop counter 3.18 F 1
Calling party address 3.5 V 3 minimumc)
Data 3.16 V 2 to Y+1a)
Segmentation 3.17 O 6b)
Importance 3.19 O 3
a)
The maximum length of this parameter depends on the length of the called party address, calling party address parameters, and the presence of optional parameters. Y is
between 160 and 254 inclusive. Y can be 254 when called party address and calling party address parameters do not include the GT, and the importance and
segmentation parameters are absent. Y can be at most 247 if the segmentation parameter is included and the important parameter is absent. See 8.3.2/Q.715.
b)
Should not be present in case of a single XUDT message.
c)
The minimum length = 2 might apply in the special case of AI = X0000000 described in 3.5.
4.19 Extended unitdata service (XUDTS)
The XUDTS message contains:
–
–
four pointers;
Table 20/Q.713 – Message type: Extended unitdata service
Length
(octets)
Data 3.16 V 2 to Y+1a)
Segmentation 3.17 O 6
Importance 3.19 O 3
a)
The maximum length of this parameter depends on the length of the called party address, calling party address parameters, and the presence of optional
parameters. Y is between 160 and 254 inclusive. Y can be 254 when called party address and calling party address parameters do not include the
GT, and the importance and segmentation parameters are absent. Y can be at most 247 if the segmentation parameter is included and the
importance parameter is absent. See 8.3.2/Q.715.

4.20 Long unitdata (LUDT)
The LUDT message contains:
–
–
four two-octet pointers;
Table 21/Q.713 – Message type: Long unitdata
Length (octets)
Long data 3.20 V 3-3954b)
Segmentation 3.17 O 6a)
Importance 3.19 O 3
a)
Originating SCCP node must include this parameter if segmentation at the relay node may be encountered in certain network configuration.
b)
See8.3.2/Q.715.
4.21 Long unitdata service (LUDTS)
The LUDTS message contains:
–
–
four two-octet pointers;
Table 22/Q.713 – Message type: Long unitdata service
Length (octets)
Long data 3.20 V 3-3954a)
Segmentation 3.17 O 6
Importance 3.19 O 3
a)
See8.3.2/Q.715.

5 SCCP Management messages and codes
5.1 General
SCCP management (SCMG) messages are carried using the connectionless service of the SCCP.
When transferring SCMG messages, class 0 is requested with no special option. The called and
calling party address parameters will refer to SSN=1 (SCMG) and will have routing indicator set to
"route on SSN". SCCP management message parts are provided in the "data" parameter of the
unitdata or extended unitdata message or "long data" of the LUDT message.
Descriptions of the various parameters are contained in the following subclauses. Format of the
SCMG message is specified in 5.3.
5.1.1 SCMG format identifier
The SCMG format identifier consists of a one-octet field, which is mandatory for all SCMG
messages. The SCMG format identifier uniquely defines the function and format of each SCMG
message. The allocation of SCMG format identifiers is shown in Table 23.
Table 23/Q.713 – SCMG format identifiers
Message Code 87654321
SSA subsystem-allowed 00000001
SSP subsystem-prohibited 00000010
SST subsystem-status-test 00000011
SOR subsystem-out-of-service-request 00000100
SOG subsystem-out-of-service-grant 00000101
SSC SCCP/subsystem-congested 00000110
5.1.2 Formatting principles
The formatting principles used for SCCP messages, as described in 1.3 and 1.4 apply to SCMG
messages.
2. SCMG message parameters
1. Affected SSN
The "affected subsystem number (SSN)" parameter field consists of one octet coded as described for
the called party address field, see 3.4.2.2.
2. Affected PC
The "affected signalling point code (PC)" parameter field is represented by two octets which are
coded as described for the called party address field, see 3.4.2.1.
3. Subsystem multiplicity indicator
The "subsystem multiplicity indicator" parameter field consists of one octet coded as shown in Figure
12.
8 7 6 5 4 3 2 1
Spare SMI
Figure 12/Q.713 – Subsystem multiplicity indicator format

The coding of the SMI field is as follows:


affected subsystem multiplicity unknown
reserved for national use
are spare.
Bits 21
00
10
11
Bits 3-8
5.2.4 SCCP congestion level
The "SCCP congestion level" parameter field consists of one octet coded as shown in Figure13.
8 7 6 5 4 3 2 1
Spare SCCP
congestion level
Figure 13/Q.713 – SCCP congestion level format
Bits 1-4 are binary coded to indicate the congestion level of the SCCP node. The values are between
1 and 8, where the value of 1 indicates the least congested condition and the value of 8 indicates the
most congested condition.
The SCCP congestion level may be subject to improvement pending further analysis of the impact of
the SCCP congestion control procedures in different network scenarios and based on the results of
operational experiences.
5.3 SCMG Messages
The SCMG messages (SSA, SSP, SST, SOR and SOG) contain mandatory fixed parameters
indicated in Table 24. These parameters are defined in the data field of the UDT, XUDT and LUDT
message.
Table 24/Q.713 – SCMG messages
(SSA, SSP, SST, SOR, SOG)
SCMG format identifier (Message type code) 5.1.1 F 1
Affected SSN 5.2.1 F 1
Affected PC 5.2.2 F 2
Subsystem multiplicity indicator 5.2.3 F 1
The SCMG message of "SCCP/subsystem-congested" (SSC) shall contain the mandatory fixed
parameters indicated in Table 25. These parameters are defined in the data field of the UDT, XUDT
and LUDT message.

Table 25/Q.713 – SSC
SCMG format identifier (Message type code) 5.1.1 F 1
Affected SSN 5.2.1 F 1
Affected PC 5.2.2 F 2
Subsystem multiplicity indicator 5.2.3 F 1
SCCP congestion level 5.2.4 F 1

ANNEX A
Mapping for cause parameter values
1. Introduction
During connection refusal/release/reset, the SCCP and its users could take necessary corrective actions, if any, only
upon relevant information available to them. Thus, it would be very helpful if those information could be conveyed
correctly.
During connection release, the "release cause" parameter in the released (RLSD) message and the N-DISCONNECT
primitive (with parameters "originator" and "reason") are used together to convey those information on the initiator and
the cause of the connection release. In addition, the N-DISCONNECT primitive is also used together with the "refusal
cause" parameter in the Connection Refused (CREF) message to convey those information during connection refusal.
During connection reset, the "reset cause" parameter in the Reset Request (RSR) message and the N-RESET primitive
(with parameters "originator" and "reason") are used together similarly.
In order to convey those information correctly, this Annex provides a guideline for the mapping of values between the
cause parameters and the corresponding N-primitive parameters during various scenarios.
2. Connection refusal
Table A.1 describes the mapping of values between the "refusal cause" parameter (3.15) and the "originator", "reason"
parameters in the N-DISCONNECT primitive (2.1.1.2.4/Q.711).
3. Connection release
Table A.2 describes the mapping of values between the "release cause" parameter (3.11) and the "originator", "reason" parameters in the N-DISCONNECT primitive
(2.1.1.2.4/Q.711).
4. Connection reset
Table A.3 describes the mapping of values between the "reset cause" parameter (3.13) and the "originator", "reason" parameters in the N-RESET primitive
(2.1.1.2.3/Q.711).
5. Return cause
There is a one-to-one mapping between the return cause of UDTS, XUDTS or LUDTS messages and the reason for return in the N-NOTICE primitives.

Table A.1/Q.713 – Mapping during connection refusal
CREF Message N-DISCONNECT primitive
Code Refusal cause Reason Originator
00000000 End user originated
Connection refusal – end user originated
NSU
00000001 End user congestion
Connection refusal – end user congestion
NSU
00000010 End user failure Connection refusal – end user failure NSU
00000011 SCCP user originated
Connection refusal – SCCP user originated
NSU
00000100 Destination address unknown
Connection refusal – destination address unknown/non-transient condition
NSP
00000101 Destination inaccessible
Connection refusal – destination inaccessible/transient condition
NSP
00000110
Network resource – QOS unavailable/non-transient Connection refusal – QOS unavailable/non-transient condition
NSPa)
00000111
Network resource – QOS unavailable/transient Connection refusal – QOS unavailable/transient condition
NSPa)
00001000 Access failure Connection refusal – access failure NSU
00001001 Access congestion Connection refusal – access congestion NSU
00001010 Subsystem failure
Connection refusal – destination inaccessible/non-transient condition
NSP
00001011 Subsystem congestion
Connection refusal – subsystem congestion
NSU
00001100
Expiration of connection establishment timer Connection refusal – reason unspecified/transient
NSPa)
00001101 Inconsistent user data
Connection refusal – incompatible information in NSDU
NSU
00001110 Reserved Reserved Reserved
00001110 Not obtainable
Connection refusal – reason unspecified/transient
NSPa)
00001111 Unqualified
Connection refusal – reason unspecified/transient
NSU
00001111 Unqualified
Connection refusal – reason unspecified/non-transient
NSP
00001111 Unqualified Connection refusal – undefined Undefined
00010000 Hop counter violation
Connection refusal – hop counter violation
NSP
00010010 No translation of such nature
Connection refusal – destination address unknown/non-transient condition
NSP
00010011 Unequipped user
Connection refusal – destination inaccessible/non-transient condition
NSP
NSU Network ServiceUser
NSP Network Service Provider
a)
When the originator is set to NSP, the causes referring to routing failures do not apply when the setup is initiated with a N-REQUEST interface element, since the routing is then done by ISUP. Only the case "SCCP user originated" with originator = NSU or those with originator = NSP and labelled with a)
are then applicable.

Table A.2/Q.713 – Mapping during connection release
RLSD Message N-DISCONNECT primitive
Code Release cause Reason Originator
00000000 End user originated Disconnection – normal condition NSU
00000001 End user congestion Disconnection – end user congestion NSU
00000010 End user failure Disconnection – end user failure NSU
00000011 SCCP user originated Disconnection – SCCP user originated NSU
00000100 Remote procedure error Disconnection – abnormal condition of transient nature NSP
00000101 Inconsistent connection data Disconnection – abnormal condition of transient nature NSP
00000110 Access failure Disconnection – access failure NSU
00000111 Access congestion Disconnection – access congestion NSU
00001000 Subsystem failure Disconnection – abnormal condition of non-transient nature NSP
00001001 Subsystem congestion Disconnection – subsystem congestion NSU
00001010 MTP failure Disconnection – abnormal condition of non-transient nature NSP
00001011 Network congestion Disconnection – abnormal condition of transient nature NSP
00001100 Expiration of reset timer Disconnection – abnormal condition of transient nature NSP
00001101 Expiration of receive inactivity timer Disconnection – abnormal condition of transient nature NSP
00001110 Reserved Reserved reserved
00001111 Unqualified Disconnection – abnormal condition NSU
00001111 Unqualified Disconnection – undefined NSP
00001111 Unqualified Disconnection – undefined Undefined
00010000 SCCP failure Disconnection – abnormal condition of non-transient nature NSP
NSU Network Service User

Table A.3/Q.713 – Mapping during connection reset
RSR Message N-RESET primitive
Code Reset cause Reason Originator
00000000 End user originated Reset – user synchronization NSU
00000001 SCCP user originated Reset – user synchronization NSU
00000010 Message out of order –
incorrect P(S)
Reset – unspecified NSP
00000011 Message out of order –
incorrect P(R)
00000100 Remote procedure error –
message out of window
00000101 Remote procedure error –
incorrect P(S) after initialization
00000110 Remote procedure error – general Reset – unspecified NSP
00000111 Remote end user operational Reset – user synchronization NSU
00001000 Network operational Reset – unspecified NSP
00001001 Access operational Reset – user synchronization NSU
00001010 Network congestion Reset – network congestion NSP
00001011 Reserved Reserved Reserved
00001100 Unqualified Reset – unspecified NSP
00001100 Unqualified Reset – undefined Undefined
NSU Network Service User
ANNEX B
International SCCP addressing and format specification
B.1 Introduction
This Annex documents a list of the assigned code values of the Translation Types (TTs), Numbering
Plan (NP) and Nature of Address Indicator (NAI), which are used to define the contents of the Global
Title Addresses Information (GTAI); as well as the types of GT-addressable SCCP user entities
allowed by the services or applications. In addition, this Annex defines the Address Indicator (AI) and
the SSN for each service or application. Guidelines are also included for application protocol
development on using the SCCP addressing information. The purpose of this Annex is to gather in
one place all the address formats which the SCCP is currently required to support in the international
network.

B.2 Guidelines on using SCCP addressing information elements in the international network
1)
If SCCP routing is to be performed using the GT and the next SCCP relay node is outside the national
network boundary, only the GT with Global Title Indicator (GTI) indicating "4" shall be sent in the SCCP
called party address. In addition, a SSN address element shall always be present in the SCCP called party
address, but its value shall be coded "0" if the SSN of the SCCP user entity was not known or not
standardized. A PC may be present in the SCCP called party address, but is not evaluated.
If SCCP routing is based on the SSN and the destination SCCP user is outside the national boundary, a
standard Q.713 SSN shall be used and the GT may be optionally included in the SCCP CdPA parameter. If the
GT is not included, the GT indicator (GTI) should be coded as "0".
2)
When the SCCP messages are to be sent across the international boundary, the Calling Party Address (CgPA)
parameter, if provided, shall include one of the following sets of SCCP address information elements to
identify the originating SCCP users depending on the coding of the RI field:
• standard Q.713 global title and SSN of "0" if the RI is "route on GT" and no standard SSN is specified;
• standard Q.713 global title and standard SSN if the RI is "route on GT";
• Q.708 ISPC and standard Q.713 SSN if the RI is "route on SSN".
If a global title is included in the calling party address parameter, the GTI shall be set to "4".
3)
In case a GT is present in the SCCP calling and/or called party addresses, the structure of the global title in the addresses shall
adhere to one of the international global title specifications in the following subclause (deviations are only possible if
multilateral agreements are obtained).
4)
If the SCCP nodes can be addressed on the international network using the Q.708 International Signalling Point Codes
(ISPCs) in the DPC of the MTP routing label, routing on SSN is also allowed; and the RI field shall indicate "route on SSN".
B.3 GT routing specification of international services
This subclause identifies the types of address format defined in the next subclause, which shall be used in the
called and/or calling party address parameters for international services requiring the SCCP GT-based routing.
Table B.1 lists the international services and the addressable SCCP user entities of their SCCP messages to be
routed on global title; and indicates the types of address formats in the called/calling party address parameters
associated with each message flow. When the "called/calling PA" entries of Table B.1 contain more than one
translation selectors, the one to be used is subject to bilateral agreement.

Table B.1/Q.713 – Called/calling party address formats for
international services requiring GT-based routing
Applications and references
Addressable SCCP user entities of messages route on GT
Called PA Calling PA
ISDN supplementary service – CCBS, Rec. Q.733.3. Entities receiving query on the busy/idle status of called parties (as defined in ISUP)
B.4.1
B.4.1
B.4.3
B.4.4
Entities receiving response about the busy/idle status of called parties (as defined in ISUP) B.4.1
B.4.3
B.4.4
B.4.1
B.4.3
B.4.4
International TelecommunicationCharge Card Calling (ITCC),
Rec. Q.736.1, Rec. E.118.
Entities receiving query to validate the card
B.4.2
B.4.3
B.4.4
Entities receiving response of card validation or subsequent messages within the same dialogue B.4.3
B.4.4
B.4.3
B.4.4
Broadband ISDN edge-to- edge applications
Entities receiving query B.4.5
B.4.3a)
B.4.4 DPC+SSN
Entities receiving response
B.4.3a)
B.4.4
DPC + SSN
B.4.3a)
B.4.4
DPC + SSN
a)
For furtherstudy.
B.4 International GT routing specification
All code values in this subclause will be specified in decimal unless specified otherwise.
B.4.1 Translation selector: TT = 17, NP = 1, NAI = 4
This translation selector identifies the type of global title used by the applications listed in the
subclause of "GT routing specification for international services".

B.4.1.1 Format of address indicator and address
See Figure B.1.
8 7 6 5 4 3 2 1
0 RI = 0 GTI = 4 SSNI = 1 PCI = 0 Octet 1
SSN = 11 Octet 2
Translation type = 17 Octet 3
Numbering plan = 1 (E.164) Encoding scheme = 1 or 2 Octet 4
0 Nature of address indicator = 4 (International) Octet 5
Country code digit 2 (if present) Country code digit 1 Octet 6
National Significant Number (NSN) digit 1 Country code digit 3 (if present) •
NSN digit 3 NSN digit 2 •
• • Octet 10
• • Octet 11
NSN digit 11 (if present) NSN digit 10 (if present) Octet 12
If needed, filler = 0 NSN digit 12 (if present) Octet 13
NOTE – The maximum number of the GTAI digits is determined by the maximum
of the E.164 numbering plan.
Figure B.1/Q.713 – Address format for TT = 17, NP = 1, NAI = 4
B.4.1.
2
B.4.
2
Translation rules
1)
A maximum of the first three digits of the GTAI are used to identify the destination country or region of the addressable
entities of this application group.
2)
The maximum number of CC + NDC digits to address an incoming international gateway to destination network is
specified in the E.164 numbering plan.
3)
The maximum number of the NSN digits used to identify a specific SCCP user entity of this application group is a
national matter or network-specific.
4)
An SSN of decimal 11 for ISDN supplementary services shall be included along with this global title in the called party
address parameter at the international interface.
Translation selector: TT = 1, NP = 0, NAI = 4
subclause of "GT routing specification of international services".

See Figure B.2.
8 7 6 5 4 3 2 1
SSN = 11 Octet 2
Numbering plan = 0 (unknown) Encoding scheme = 1 or 2 Octet 4
Second digit of E.118 number First digit of E.118 number Octet 6
Forth digit of E.118 number Third digit of E.118 number Octet 7
Sixth digit of E.118 number Fifth digit of E.118 number Octet 8
Eighth digit of E.118 number Seventh digit of E.118 number Octet 9
• • •
• • •
If needed, filler = 0 Last digit of E.118 number •
NOTE – The maximum number of the GTAI digits is determined by the maximum number of digits specified in the E.118
numbering plan.
Figure B.2/Q.713 – Called party address format for TT = 1, NP = 0, NAI = 4
B.4.2.2
1)
2)
3)
4)
B.4.3
Translation rules
A maximum of the first seven digits of the GTAI, are used to identify the card issuers, which
administer the entities receiving card validation query and ITCC call disposition message.
These digits are referred to "Issuer Identification Number" (IIN).
If the first two digits are "89", the following 1/2/3 digits (third through fifth digit) shall
indicate Country Codes (CCs) of the card issuers according to the E.164 assignment. The
format of the Issuer Identifier (II) that follows the CC, is a national matter.
The maximum number of the GTAI digits used to identify a specific SCCP user entity of this
application group is determined by the issuer and is network-specific.
An SSN of decimal 11 for ISDN supplementary services shall be included along with this
global title in the called party address parameter at the international interface.

See Figure B.3.
8 7 6 5 4 3 2 1
SSN = 0 or standard SSN Octet 2
Numbering plan = 2 Encoding scheme = 1, 2 or 3 Octet 4
Q.708 U digit (most significant) Q.708 Z digit Octet 6
Q.708 U digit (least significant) Q.708 U digit Octet 7
0 (Filler) Q.708 V digit Octet 8
National significant part Octet 9
National significant part •
• •
• •
• •
Figure B-3/Q.713 – Address format for TT = 2, NP = 2, NAI = 4
Octet 6 to 8 is called the "Q.708 Part" and its encoding scheme shall be encoded in BCD. The Q.708
Z-UUU digits are decimal representation of the Q.708 Signalling Area/Network Codes (SANCs) of
the final destination countries, new code values are published regularly in the Operational Bulletin of
the ITU.
Encoding for the national significant part is determined by the originating network and shall be
indicated by the encoding scheme field of octet 4.
B.4.4
B.4.3.2 Translation rules
1) Only the Q.708 part of the GTAI shall be translated for routing in the international network.
2) The format of the National Significant Part (NSP) is a national matter. The maximum length
of NSP is network-specific.

See Figure B.4.
8 7 6 5 4 3 2 1
SSN = 0 or international standard value Octet 2
Numbering plan = 1 (E.164) Encoding scheme = 1 or 2 Octet 4
National Destination Code (NDC) Digit 1 Country code digit 3 (if present) Octet 7
NDC digit 3 (if present) NDC digit 2 (if present) Octet 8
NDC digit 5 (if present) NDC digit 4 (if present) Octet 9
Equipment identification digit 2 Equipment identification digit 1 Octet 10
• • •
If needed, filler = 0 Equipment identification digit N (if present) Octet M
NOTE – The maximum number of the GTAI digits is determined by the maximum of the E.164 numbering plan.
The GTAI is formatted according to the E.164 numbering plan. It consists of the E.164 country
codes, followed by the nationally-assigned NDC and the network-specific or operator-assigned
equipment identification digits of the signalling point. This GT, together with the SSN,
unambiguously identifies a particular SCCP user entity in the network.
B.4.4.2
1)
2)
3)
Translation rules
A maximum of the first three digits of the GTAI are used to identify the destination country
or region of the addressable entities. For destination countries with only one operator,
translation of the CC should be sufficient.
For destination countries with multiple network operators, only the CC and NDC are
translated within the international network to identify the destination networks.
Translation of additional digits (i.e. equipment identification) to identify a specific SCCP
user entity is a national matter or network-specific.
B.4.5 Translation selector: TT = 3, NP = 1, NAI = 4
subclause of "GT routing specification for international services".

See Figure B.5.
8 7 6 5 4 3 2 1
SSN = 13 Octet 2
Translation type = 3
Octet 3
Numbering plan = 1 (E.164) Encoding scheme = 1 or 2
Octet 4
0 Nature of address indicator = 4 (International)
Octet 5
National significant N = number (NSN) digit 1 Country code digit 3 (if present) •
NSN digit 3 NSN digit 2 •
• • Octet 10
• • Octet 11
NSN digit 11 (if present) NSN digit 10 (if present) Octet 12
If needed, filler = 0 NSN digit 12 (if present) Octet 13
NOTE – The maximum number of the GTAI digits is determined by the maximum of the E.164 numbering plan.
B.4.5.2
1)
2)
3)
4)
Translation rules
A maximum of the first three digits of the GTAI are used to identify the destination country
or region of the addressable entities of this application group.
The maximum number of CC + NDC digits to address an incoming international gateway to
destination network is specified in the E.164 numbering plan.
The maximum number of the NSN digits used to identify a specific SCCP user entity of this
application group is a national matter or network-specific.
An SSN of decimal 13 for broadband ISDN edge-to-edge applications, which will be
transferred along with this global title in the called party address parameter, shall be
provided by the originating application entity.

REFERENCES
• https://www.3gpp.org.
• https://www.slideshare.net.
• https://www.itu.int.
• Gsm by Jorg Eberspacher
https://www.goodreads.com/book/show/1647525.GSM_Archit
ecture_Protocols_and_Services
(https://www.goodreads.com/author/show/6657410.J_rg_Eber
sp_cher).
• UMTS Signaling UMTS Interfaces, Protocols, Message Flows and
Procedures Analyzed and Explained by Ralf Kreher and Torsten
R¨udebusch.

(https://www.wiley.com/en-
us/UMTS+Signaling%3A+UMTS+Interfaces%2C+Protocols%2C+M
essage+Flows+and+Procedures+Analyzed+and+Explained%2C+
2nd+Edition-p-9780470065334).
• GSM Networks: Protocols, Terminology & Implementa
by Gunnar Heine
(https://www.goodreads.com/book/show/1060116.GSM_Networ
ks).
• http://4g5gworld.com/ltefaq/what-are-lte-protocols-
specifications.
• ITU-T Recommendation Q.713 was revised by ITU-T Study
Group 11 (1993-1996) and was approved under the WTSC
Resolution No. 1 procedure on the 9th of July 1996.

Big dreams drive the human
spirit to greatness

• Gholamreza Ranjbar asri
• gra1348@yahoo.com
• M.Ali.Vahedifar
• Vahedifarali@yahoo.com

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