Optimization of ipv6 packet’s headers over ethernet

International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
INTERNATIONAL JOURNAL OF ELECTRONICS AND
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 1, January- February (2013), © IAEME
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 4, Issue 1, January- February (2013), pp. 99-111
IJECET
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Journal Impact Factor (2012): 3.5930 (Calculated by GISI) ©IAEME
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OPTIMIZATION OF IPV6 PACKET’S HEADERS OVER ETHERNET
FRAME

Fahim A. Ahmed Ghanem1, Vilas M. Thakare2
1
School of Computational Sciences, Swami Ramanand Teerth Marathwada University,
Nanded, India,Fahmed_11@yahoo.com
2
Post Graduate Department Of Computer Science, Faculty of Engineering & Technology,
Amravati University, Amravati, India, vilthakare@yahoo.co.in

ABSTRACT

This paper aims to optimize the current IPv6 packet structure by reducing the size of
the headers, increasing the size of the data, reducing packet processing time and speed up the
data transmission.

Keywords: Ethernet Frame, IPv6, UDP, TP/IP.

I. INTRODUCTION

The current IPv6 Packet’s scheme has several fields to be carried and transmitted in
each packet even if the source, the destination and the payload of the packets are same. These
fields utilize packet space and thus decrease the size of user data. Therefore the processing of
each packet requires more time and delay of end-to-end transmission. While data
transmission, data has to be broken down into similar structures of the packets, which are
reassembled to the original data chunk once it reaches the destination. A packet is also called
a datagram, a segment, a block, a cell or a frame, depending on the protocol.

II. OBJECTIVE OF THIS STUDY

This paper aims to optimize data transmission by redesigning OSI packet structure by
dividing packets into master packet and slave packet, decreasing the size of packet’s header
and increase the size of the data while maintaining the same current packet size. This
optimization aims to reduce the processing time as a result of reducing the contents of
processed headers.
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III. OSI MODEL LAYERS

Before we start with packet optimization, it will be helpful to have a quick review of
the OSI model packet’s construction. In this section we will have a look through OSI model.
There are two types of header fields:

a. Variable Fields: fields that it is information from packet to packet and has to be repeated
information
in each packet.
b. Invariable Fields (Tagged with Inv.): field that it is information doesn’t vary from packet
to other and doesn’t have to be repeated in each packet.

Open Systems Interconnection (OSI) model (ISO/IEC 7498-1) is a product of the Open
1)
Systems Interconnection effort at the International organization for Standardization It is a
Standardization.
prescription of characterizing and standardizing the functions of a communications system in
terms of abstraction. Similar communication functions are grouped into logical layers. A
layer serves the layer above it and is served by the layer below it.
There are seven interconnection layers start from up to down (layer 7 to layer 1)
prospectively. Application forwards user data to Presentation layer which forwards it to
Session layer. Session layer forwards data user to Transportation layer. Transport layer adds
layer.
the header and sent the segment to Network layer which adds header and forward the packet
to Data link layer. Data link adds the header and forward the frame to Physical layer.

Fig. 1 full Ethernet frame (TCP)

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0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 1, January February (2013), © IAEME
January-

Fig. 2 full Ethernet frame (UDP)

Fig. 3 OSI 7 layers’ hierarchy

In this paper, we will concentrate on layer 4, layer 3 and layer 2 headers. We will
ignore layer 7, layer6 and layer 5 headers as it is variables from application to other.

1 Transport Layer Headers
Transport layer contains either TCP or UDP headers:
1.1 TCP Header
The Transmission Control Protocol (TCP) is one of the core protocols of the Internet
Protocol Suiteprovides reliable, ordered delivery of a stream of bytes from a program on one
provides
computer to another program on another computer. TCP is the protocol that major Internet

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applications such as the World Wide Web, email, remote administration and file transfer rely
on.Below description displays the contents of TCP header contents:
a.
Source Port (inv.): indicates source port number.
Destination Port (inv.): indicates destination port number.
b.
c.
Sequence Number: the sequence number of the first data octet in this segment.
Acknowledgment Number: if the ACK control bit is set this field contains the value of
d.
the next sequence number the sender of the segment is expecting to receive.
e. Data offset (inv.): this indicates where the data begins.
f. Reserved (inv.): reserved for future use. Must be zero.
g. Control Bits:
1 URG: Urgent Pointer field significant
2 ACK: Acknowledgment field significant
3 PSH: Push Function
4 RST: Reset the connection
5 SYN: Synchronize sequence numbers
6 FIN: No more data from sender
7 Window: the number of data octets beginning with the one indicated in the
acknowledgment field which the sender of this segment is willing to accept.
h. Checksum: the checksum field is the 16 bit one's complement of the one's
complement sum of all 16 bit words in the header and text.
i. Urgent Pointer (inv.): this field communicates the current value of the urgent pointer
as a positive offset from the sequence number in this segment.
j. Options (inv.): variable, Options may occupy space at the end of the TCP header and
are a multiple of 8 bits in length.
k. Padding (inv.): variable, the TCP header padding is used to ensure that the TCP
header ends.
TCP header is 20 bytes without optional fields.
1.2 UDP Header
UDP is a connectionless protocol that provides an unreliable data services [1]. UDP is
one of the core members of the Internet Protocol Suite, the set of network protocols used for
the Internet. With UDP, computer applications can send messages to other hosts on an
Internet Protocol (IP) network without requiring prior communications to set up special
transmission channels or data paths. UDP applications must generally be willing to accept
some loss, errors or duplication. Some applications such as TFTP may add rudimentary
reliability mechanisms into the application layer as needed [2]. UDP provides
application multiplexing (via port numbers) and integrity verification (via checksum) of the
header and payload [3]. UDP is suitable for purposes where error checking and correction is
either not necessary or performed in the application, avoiding the overhead of such
processing at the network interface level [4].
Below description displays the contents of UDP header contents:
a. Source port (inv.): It identifies the sender's port.
b. Destination port (inv.): it identifies the receiver's port.
c. Length, it specifies the length in bytes of the entire datagram: header and data.
d. Checksum: It is used for error-checking of the header and data. If no checksum is
generated by the transmitter, the field uses the value all-zeros [5].
UDP header varies from 4 to 8 bytes.
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2 Network Layer Header
Network layer header consists of 8 fields. IPv6 packet may contain any number
optional header called extension. Below description explains the contents of network layer
header contents:

a. Version (inv.): indicates internet protocol version 6.
b. Traffic Class (inv.): indicates traffic class field.
c. Flow Label (inv.): originally created for giving real-time application special service
[6]. The flow label when set to a non-zero value now serves as a hint to routers and
switches with multiple outbound paths that these packets should stay on the same
path so that they will not be reordered [7][8]. It has further been suggested that the
flow label be used to help detect spoofed packets.
d. Payload Length: specifies the length of IPv6 packet, i.e., the rest of the packet
following this IPv6 header in octets.
e. Next Header (Inv.): identifies the type of header immediately following the IPv6
header.
f. Hop Limit: maintains a counter that gradually decrements down to zero, at which
point the datagram is discarded. This keeps packets from looping endlessly.
g. Source Address (inv.): specifies the originator of the packet.
h. Destination Address (inv.): specifies the receiver of the packet.
IPv6 header’s size is 40 bytes without extensions.

3 Data Link Header and Tailor (802.3 IEEE)
Data link is a chunk of data that is packaged for transmission over network [9].
Frame header and Tailor consist of 4 fields.Ethernet II framing(also known as DIX Ethernet)
named after DEC, Intel and Xerox, the major participants in its design.Below description
display the contents of Ethernet header:
a. Destination Address (Inv.): It specifies either a single recipient node (unicast mode),
a group of recipient nodes (multicast mode), or the set of all recipient nodes
(broadcast mode).
b. Source Address (Inv.): sender's globally unique node address. This may be used by
the network layer protocol to identify the sender, but usually other mechanisms are
used (e.g. arp). Its main function is to allow address learning which may be used to
configure the filter tables in a bridge.
c. LLC Header (Inv.): it contains DSAP, SSAP and control byte.
d. CRC: this field is added at the end of the frame (trailer) and provides error detection
in the case where line errors (or transmission collisions in Ethernet) result in
corruption of the MAC frame. Any frame with an invalid CRC is discarded by the
MAC receiver without further processing. The MAC protocol does not provide any
indication that a frame has been discarded due to an invalid CRC.

The size of Ethernet header along with CRC is 21 bytes.
As per the above overview of OSI models and based on the traffic type, Ethernet
frame can contains two types of segment headers: TCP header or UDP header. The minimum
accumulated headers size within Ethernet frame (TCP header + L3 header + L2 header and
tailor) is 81bytes.In sample case, if we have a TCP/IP sentence contains of 50,000 bytes, this
sentence will be divided into small chunks called frames and the maximum size of each
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frame will not exceed 1518 bytes. Headers will consume minimum of 81 byte out of
1518 and the remaining 1437 bytes will be available for user data, so 50,000 bytes
will be transmitted over 35 packets as a result of dividing 50,000 by 1437.
The minimum accumulated headers size within Ethernet frame (UDP header + L3
header + L2 header and tailor) is 65 bytes. The maximum size of Ethernet packet will
not exceed 1518 bytes. Headers consume minimum of 65 bytes out of 1518 and the
remaining 1453 bytes will be available for data. According to the above data, we
observe that we are facing two obstacles: first one is the size of the headers and the
other one is the processing of those headers. Headers consume some packet’s size and
most of the data in the header sections is repeated in all packets and it is processed in
each middle device till it reaches the destination.

IV. STEPS OF OPTIMIZATION

Optimization steps are divided into two stages:
1 Headers Optimization:
It contains creation of master and slave packet.
2 Packet Transmission:
Packet’s processing divided into two steps
a. Processing of Master packet.
b. Processing of Slave packet.

1 Headers Optimization
1.1 Proposed Master Packet
The proposed Master packet contains all header fields (Variables, Invariable,
along with ID and Tag Fields) but without user data field.
1.1.1 Transport Layer Master Segment
The proposed transport layer Master segment contains all Transport layer
header fields (Variables, Invariable, along with ID and Tag Fields) but without user
data field.
1.1.1.1 TCP Master Segment
The proposed TCP Master segment is created when transport layer receives
first packet in the session from session layer in order to be transmitted to the desired
destination.
The contents of Master TCP segment are same contents of OSI TCP header with extra
two fields:

a. ID: 1 bit indicates the type of the packet, as value 1 indicates Master segment and
value 0 indicate slave packet.
b. Tag: 31 bits, is a unique ID for each session, the value of tag will be maintained
same till session is closed.

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Fig. 4 Proposed full master (TCP)Ethernet frame

1.1.1.2 UDP Master Segment
The proposed UDP Master segment is created when transport layer receives first
packet for each session from session layer in order to be transmitted to the desired
destination. The contents of Master UDP segment are same as the contents of OSI UDP
header with extra ID and Tag fields. The roles of these two fields are same as the role of TCP
master segment.

Fig. 5 Proposed full master (UDP) Ethernet frame

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1.1.2 Network Layer Master Packet
The proposed Network layer header is added to the segment received from transport
layer. The contents of Master packet are same the contents of network layer header of OSI
model with extra ID and Tag fields. The roles of these two fields are same as the role of
transport layer for Master segment.
1.1.3 Data Link Master Frame
The proposed Ethernet header is added to the packet received from network layer. The
contents of Master frame header are same the contents of Ethernet header of OSI model with
extra ID and Tag fields. The roles of these two fields are same as its role in transport layer
Master segment.
The size of Master Frame (TCP header) is the size of the layer 4, layer 3, layer 2
headers and tailor only without user Data which is minimum 85 bytes (without optional
s
fields). The size of Master (UDP headed) is the size of the layer 4, layer 3, layer 2 headers
and tailor only without Data which is minimum 65 bytes.

1.2 Proposed Slave Packet
Slave packet contains only invariable header fields in addition to ID and Tag fields
addition
along with user data.
1.2.1 Transport Layer Slave Segment
The proposed transport layer segment contains invariable header fields in addition to
ID and Tag fields along with user data.
1.2.1.1 TCP Slave Segment
The proposed TCP segment header contains only invariable header fields in addition
contains
to ID and Tag Fields along with data. The size of the header is 134 bits equals to 17 bytes.

Fig. 6 Proposed full slave (TCP) Ethernet frame

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1.2.1.2 UDP Slave Segment
The proposed UDP segment header contains only invariable header fields in addition to ID
and Tag Fields along with data. The size of the header is 64 bits equals to 8 bytes.
1.2.2 Network Layer Slave packet
The proposed layer 3 header contains only invariable header fields in addition to ID
and Tag Fields along with user data. The size of the layer 3 header is 48 bits equals to 6
bytes.
1.2.3 Ethernet Layer Slave Frame
The proposed layer 2 Frame contains only invariable header and Tailor fields in
addition to ID and Tag Fields along with user data. The size of Ethernet header and tailor is
64 bits equals to 8 bytes.

Fig. 7 Proposed full slave (UDP) ethernet frame

2 Packet Transmission
Packet transmission includes the process of transmission of master and slave packets
from source to destination.
2.1 Master Packet’s Transmission
2.1.1 Master TCP Segment, Packet and Frame Transmission

a. Application layer of the source station forwards user data to Presentation which forwards
it to Session which also forwards it to transport layer.
b. Transport layer buffers the received user data, creates one master TCP segment and
forward it to network layer.
c. Network layer adds Network layer master header to the received segment and send the
packet to Ethernet layer.
d. Ethernet layer adds Ethernet master header and tailor and sends the frame to physical
frame
layer.
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e. Physical layer adds it is header sends it to another station or middle devices towards
destination.
f. Ethernet layer in layer 2 device checks the packet ID and identify whether it is Master
packet or Slave packet by value of ID (1= master and 0 = slave).
g. If the value ID is 1, Ethernet layer processes Master packet as the processing of OSI
model packet based on source, destination and content etc. and decide the next hop MAC.
h. Ethernet layer cashes the frame processing result, save it in the forwarding table along
with frame’s Tag and send the frame towards the destination.
i. If the next hop is layer 2, steps f, g, and h will be repeated.
j. If the next hop is layer 3 device, layer 3 checks the packet ID and identify whether it is
Master Packet or Slave Packet by value of ID (1= master and 0 = slave).
k. If value ID is 1, layer 3, layer 3 processes master packet as OSI model processing based
on source, destination and content etc. and decide the next hop IPv6.
l. Layers 3 cashes the processing result, save it in the forwarding table along with packet’s
Tag and forwards the packet towards the destination.
m. If the next hop is layer 3, steps j, k, and l will be repeated.
n. If the next hop is layer 4, layer 4 processes the segment as per layer 2 and layer 3 and
forwards it to next hop or layer.
o. Steps f – n will be repeated till packet reaches the destination.
p. Once Transport layer of source station receives the acknowledgement about receiving
Master packet from the destination, it starts creating and sending slave segments.
Note: master TCP packet was sent only one time per each session.

2.1.2 Master UDP Segment, Packet and Frame Transmission
Transmission of master UDP packet takes steps from a - n of TCP packet but not step
o, because UDP packet doesn’t rely on acknowledgment.
Note: master UDP packet being transmitted every 5 seconds in order to insure continuously
delivering of packets in case there is any transmission or processing issue in the middle
devices.

2.2 Slave Packet’s Transmission
2.2.1 Slave TCP Segment, Packet and Frame Transmission
a. Source transport layer creates either TCP or UDP slave header and sends the segment to
Network layer.
b. Network layer adds it is slave header and sends the packet to Ethernet layer.
c. Ethernet layer adds it is slave header and tailor and sends it to physical layer.
d. Physical layer adds it is header and forwards it towards the destination.
e. Ethernet layer of the destination station or middle devices checks the packet ID and
identify whether it is Master Frame or Slave Frame by value ID (1= master and 0 =
slave).
f. If the value ID is 0, layer 2 matches the Tag with forwarding table information and
forwards it to the next hope without any extra processing.
g. If there is no information about the Tag in the forwarding table, layer 2 simply drops the
packet.
h. If the next hope is layer 2, step e and f will be repeated.

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i. If the next hope is layer 3 device of the destination station, layer 3 will check the packet
ID and identify whether it is Master Frame or Slave Frame by value ID (1= master and 0
= slave).
j. If the value ID is 0, layer 3 matches packet Tag with forwarding table information and
forwards it to the next hope without any extra processing.
k. If there is no information about the Tag in the forwarding table, layer 3 simply drops the
packet.
l. If the next hope is layer 3, step i and j will be repeated.
m. If the next hop is layer 4, layer 4 processes the segment like layer 2 and layer 3 and
forwards it to next layer.
n. Steps e to mwere repeated till packet reaches the destination.
o. Packet acknowledgment was sent as OSI model.
2.2.2 Slave UDP Segment, Packet and Segment Transmission:
Transmission of slave UDP segment, packet and frame takes is same as steps from a - n of
TCP packet but not step o, because UDP packet doesn’t rely on acknowledgment.
Note: master UDP packet was sent every 5 seconds in order to insure continuously
delivering of the packets in case there is any transmission or processing issue in the middle
devices.
Slave Ethernet packet (TCP header + L3 header + L2 header and tailor) is fixed to 31
bytes whether master packet contains extension headers fields or not. Slave Ethernet packet
(UDP header + L3 header + L2 header and tailor) is fixed to 22 bytes whether master packet
contains optional fields or not.
V. VERIFICATION
Optimization of Packet header and packet transmission optimization gives ability to
transmit more user data along with small headers and less processing time which increase the
efficiency of the existing and feature network infrastructure.
Below two Tables and two charts illustrate the comparison between ISO model and
new proposed optimized packet where we observe the decreased size of Ethernet packet
headers using TCP layer 4 and using UDP layer 4. The total size of headers for optimized
IPv6 packet over Ethernet (TCP header + IPv6 header + Ethernet header and tailor) is
38.27% of OSI headers .The total size of Ethernet headers for optimized Ethernet (UDP
header + IPv6 header + Ethernet header and tailor) is 33.8% of OSI headers.
This experiment reduces the size of IPv6 packet 61.7% for TCP segment and 66.2% for UDP
segment.
Table 1 comparison between OSI headers (TCP) and optimized packet headers
IOS Headers (TCP) without
Optimized Headers
optional fields
TCP Header 20 17
IPv6 Header 40 6
Frame Header 21 8
Total headers
81 31
(bytes)

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Table 2 comparison between OSI headers (UDP) and optimized packet headers
IOS Headers (UDP) without
Optimized Headers
optional fields
UDP Header 4 8
IPv6 Header 40 6
Frame Header 21 8
Total headers (bytes) 65 22

Fig. 8 comparison chart between OSI headers (TCP) and optimized packet headers

Fig. 9 comparison chart between OSI headers (UDP) and optimized packet headers

VI. CONCLUSION

Referring to figures 8 through 9, the new proposed IPv6 packet structure and IPv6
packet transmission decreases the size of headers between 61% up to 66%. Decreasing the
headers’ space give an opportunity to increase the size of user data while maintaining same
frame size. Moreover, reducing the size of the headers will reduce the processing times as
headers
middle devices or layers will only process Master packet, cash the processing result and
apply the result to all Slaves packets which belong to same session.The proposed
optimization solution can be applied to the current and new network infrastructure in order to
increase the efficiency of the networks.

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VII. REFERENCES

[1] Michael A. Gallo, William M. Hancock, “Computer Communications and Networking
Computer
Technologies”, New Delhi, India, Cengage Learning India Private Limited.
Limi
[2] Forouzan, B.A. “TCP/IP: Protocol Suite, 1st edition”, New Delhi, India, Tata McGraw
McGraw-
Hill Publishing Company Ltd.
[3] Clark, M.P., “Data Networks IP and the Internet, 1st edition”, West Sussex, England,
John Wiley & Sons Ltd.
[4] Andrew S. Tanenbaum, “Computer Networks 4th Edition”, Amsterdam, the Netherland,
Computer Edition”,
Prentice Hall PTR.
[5] Barrie Sosinsky, “Networking”, New Delhi, India Wily India Pvt. Ltd. 2010.
,
[6] Deering S., Hinden R. “Internet Protocol, version 6” IETF. RFC 2460, (December 1998)
Internet
[7] Wijnen, B. “Textual Conventions for IPv6 Flow Label”, IETF. RFC 3595. (September
Textual Label
2003).
[8] Amante, S.; Carpenter, B.; Jiang, S.; Rajahalme, J. “IPv6 Flow Label
“IPv6
Specification”, IETF. RFC 6437 (November 2011).
2011)
[9] Kurose, J. F., Ross, K. W. “Computer Networking: A Top-Down Approach (5th ed.)”,
Top Down
Boston, MA, Pearson Education. ISBN 978-0-13-136548-3.

Mr. Fahim A. Ahmed Ghanem is a Ph.D. student at School of
Computational Sciences, SWAMI RAMANAND TEERTH
MARATHWADA UNIVERSITY, Nanded, India. He is doing research in
field of IP Network Optimization. He received MSC-IT degree from SMU,
MSC IT
India 2005 – 2007. He is a dual CCIE R&S and SP. Hewoks as a Senior
Network Engineer in mobily co. KSA.

Mr. Vilas Mahadeorao Thakare, has received his M.E. degree in field of
Thakare d
Advance Electronics, received his M.Sc. degree in field of Applied
Electronics, Diploma in Computer Management. He was obtained his PhD
in field of Computer Science.

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Optimization of ipv6 packet’s headers over ethernet

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