DSDV Protocols by Mr.Darwin Nesakumar A, AP/ECE, R.M.K.Engineering College

DSDV : Destination-Sequenced Distance
Vector Protocol
By
Mr. Darwin Nesakumar A, M.E., (P.hD)
Assistant Professor
Department of ECE
R. M. K. Engineering College
“I measure the progress of a community by the degree of progress which women have achieved”.-
Dr.B.R.Ambedkar, P.hD
Welcome

Agenda
 Review of previous session
 Routing Protocols Introduction
 DSDV : Destination-Sequenced Distance Vector Protocol
 Quizzes
Thursday, July 30, 2020 DSDV Protocol

Review of previous session
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IMPORTANT POINTS TO BE REMEMBER
MANETs
• Multi Hop Relaying Network
• No fixed infrastructure
• No Pre existing Infrastructure
• Dynamic network topology
• Nodes in the network are mobile in general
• No central Controller ( To serve as server)
• The wireless hosts in MANET communicate
with each other without existing of fixed
infrastructure and without central controller
• Decentralized Network
• Cooperative Communications
• Heterogeneous in nature
• Device to Device Communication
• A MANET can be connected to other fixed
network or to the internet
• Limited bandwidth and power
• No peer – peer communication
• Multipath Propagation
• Proactive / Reactive Protocols
• CSMA/CA Protocol to avoid hidden
terminal problem

Issues in MANETs
• Computation, storage, and communications
capabilities and interoperability
• Identification of neighbouring devices and
their corresponding attributes
(Characteristics).
• Battery capacity
• Limitations imposed by Mobility
• Dynamically changing topologies/routes
• Lack of mobility awareness by
system/applications
• Limitations of the Mobile Computer
• Short battery lifetime
• Packet loss due to transmission errors
• Mobility-induced route changes
• Mobility-induced packet losses
• Variable capacity links
• Frequent disconnections/partitions
• Limited communication bandwidth
• Broadcast nature of the communications
• Hidden terminal problem
• Limited wireless transmission range
• Ease of snooping on wireless transmissions
(security hazard)
• Quality of Service

Applications of MANETs
Tactical Network - Military Communications, Telecommunication Network
Sensor Networks - Environmental / Earth Sensing -Air Pollution Monitoring, Forest Fire detection,
Water Quality Monitoring, Natural Disaster Monitoring, Industrial Monitoring - Machine health
monitoring, Data Logging, Health care monitoring - Implanted devices, Wearable devices,
Environment-embedded systems, Waste water monitoring, Area Monitoring
Emergency Services - Search and rescue -Crowd control, Commando operations, Disaster recovery
Sensors used to sense the natural disasters, Replacement of a fixed infrastructure in case of
earthquakes, hurricanes, fire, Emergency operations -108 Ambulance, Using Google Maps, KAVALAN
App, Policing and fire fighting
Location Based Services - Automatic call forwarding, Google Maps – SWIGY, OLA, UBER, OYO,
AMAZON, FLIPCART & all online based service applications, WhatsApp, Face Book, We Chat, Arokya
Setu APP – COVID 19

Applications of MANETs
Home and enterprise Networking- Home/office wireless networking(WLAN), e.g., shared
whiteboard, application, Use PDA (Personal Digital Assistant) to print anywhere – Bus, Super Market,
Personal area network (PAN) ,Cell phone, laptop, ear phone, SMART wrist watch, Mobile Hotspot
Educational Applications - Set up virtual classrooms or conference rooms, Google MEET, Zoom
Communications, Microsoft Meeting, My Meeting, Set up ad hoc communication during
conferences, meetings, or lectures
Commercial applications- E-commerce - Electronic payments from anywhere(Ex. In taxi) – Google
PAY, Phone Pay, PayTM, Business, Dynamic access to customer files stored in a central location.
Mobile – AADHAAR, Vehicular services -Transmission of news ,road conditions ,weather, Local ad hoc
network with nearby vehicles for road/accident guidance, Civilian environments - Taxi cab network,
Meeting rooms, Sports stadiums, Boats, small aircraft
Entertainment - Multiuser games – PUBG, Robotic pets, Outdoor internet access, Online Games -
Cricket – Tennis – Foot Ball, Online FUN Quizzes – Multiple Participants, Online Movies – NETFLIX,
AMAZON PRIME etc.

Classification of routing protocols
1. Routing information update mechanism - Proactive, Reactive, Hybrid
2. Usage of temporal information (e.g. cached routes): - Past temporal , Future temporal
3. Usage of topology information - Flat, Hierarchical
4. Usage of specific resources - Power-aware routing, Geographical information assisted routing

Routing Protocols
Routing Protocols
Reactive ProtocolHybrid Protocol Proactive Protocol

ROUTING PROTOCOLS
Proactive
Table-Driven Routing Protocol
• Continuously evaluate the routes
• Attempt to maintain consistent, up-to-
date routing information
• When a route is needed, one may be
ready immediately
• When the network topology changes,
the protocol responds by propagating
updates throughout the network to
maintain a consistent view
• Each node maintains a routing table which
stores - next hop, cost metric towards each
destination, a sequence number that is
created by the destination itself
• Each node periodically forwards routing
table to neighbors
• Each node increments and appends its
sequence number when sending its
local routing table
• Each route is tagged with a sequence
number; routes with greater sequence
numbers are preferred
• Each node advertises a monotonically
increasing even sequence number for itself
• When a node decides that a route is broken,
it increments the sequence number of the
route and advertises it with infinite metric
• Destination advertises new sequence
number .
• Example DSDV (Destination Sequenced
Distance Vector)

ROUTING PROTOCOLS
Proactive
Table-Driven Routing Protocol
• Maintain routes between every host pair at
all times
• Based on periodic updates; High routing
overhead
• Traditional distributed shortest-path
protocols
• Determine routes independent of traffic
pattern
• Traditional link-state and distance-vector
routing protocols are proactive
• Route from each node to every other node
in the network
• Periodic route-update packets
• Large routing tables
• Routes are ready to use instantaneously

Reactive
On-Demand Routing Protocol
• On-demand style: create routes only
when it is desired by the source node
• The route is discovered only when it is
required/needed
• Process of route discovery occurs by
flooding the route request packets
throughout the mobile network.
 Route Maintenance:
This phase performs the maintenance
work of the route as the topology in
the mobile ad-hoc network is dynamic
in nature
 Route Discovery:
This phase determines the most
optimal path for the transmission of
data packets between the source and
the destination mobile nodes
 Route discovery invokes a route-
determination procedure
• The procedure is terminated when
• A route has been found
• No route is found after all
route permutations are
examined
• Longer delay: sometimes a route may
not be ready for use immediately when
data packets come
• Example AODV (Ad hoc On-Demand
Distance Vector)
ROUTING PROTOCOLS

• Flood is propagated outwards from the
source
• Pure flooding = every node transmits the
request only once
• Source floods the network with a Route
Request packet when a route is not
available to the required destination
• Destination send the Route reply to Route
Request
• Reply uses reversed path of Route Request
• Sets up the forward path
On-Demand Routing Protocol
• Determine route if and when needed
• Source initiates route discovery
• Maintain routes only if needed
• Example: DSR (dynamic source routing)
• Routes from Source to Destination only
• Routes constructed when needed, higher
connection setup delay
• Route update when necessary
• Small or No routing tables
Reactive
ROUTING PROTOCOLS

DSDV
Destination-Sequenced Distance-Vector
Routing Protocol

Outline
 Introduction
 Distance-Vector
 DSDV Protocol
 Summary

Introduction
 The property of ad-hoc networks
 Topology may be quite dynamic
 No administrative host
 Hosts with finite power

Introduction
 The properties of the ad-hoc network routing protocol
 Simple
 Less storage space
 Loop free
 Short control message (Low overhead)
 Less power consumption
 Multiple disjoint routes
 Fast rerouting mechanism

Introduction
 Routing Protocol:
 Table-driven (proactive)
 Source-initiated on-demand (reactive)
 Hybrid
 Routing Algorithm
 Link-State algorithm:
 Each node maintains a view of the network topology
 Distance-Vector algorithm:
 Every node maintains the distance of each destination

Question
In link state algorithm each node maintains
Network topology
Distance of each destination

Answer for the Question
Network topology

Link-State
 Like the shortest-path computation method
 Each node maintains a view of the network topology
with a cost for each link
 Periodically broadcast link costs to its outgoing links to
all other nodes such as flooding

Link-State
E
B
D
G
H
F
A
C
link costs

Question
In link state algorithm _________broadcast link costs to its outgoing
links to all other nodes such as flooding
Periodically
Never
Only Once

Periodically

Distance-Vector
 known also as Distributed Bellman-Ford or RIP (Routing
Information Protocol)
 Every node maintains a routing table
 all available destinations
 the next node to reach to destination
 the number of hops to reach the destination
 Periodically send table to all neighbors to maintain
topology

Question
In distance Vector periodically send table to __________
neighbors to maintain topology
All
Close
Few

All

Distance Vector (Tables)
C
Dest. Next Metric …
A A 1
B B 0
C C 2
A A 0
B B 1
C B 3
1 2
A B 3
B B 2
C C 0
BA

(A, 1)
(B, 0)
(C, 1)
(A, 1)
(B, 0)
(C, 1)
Distance Vector (Update)
C
A A 1
B B 0
C C 1
A A 0
B B 1
C B 3 2
1 1
A B 3 2
B B 1
C C 0
BA
B broadcasts the new routing
information to his neighbors
Routing table
is updated

(D, 0)
(A, 2)
(B, 1)
(C, 0)
(D, 1)
(A, 1)
(B, 0)
(C, 1)
(D, 2)
Distance Vector (New Node)
C
1 1
BA D
1
broadcasts to update
tables of C, B, A with
new entry for D
A B 2
B B 1
C C 0
D D 1
A A 1
B B 0
C C 1
D C 2
A A 0
B B 1
C B 2
D B 3

Distance Vector (Broken Link)
C
1 1
BA D
1
Dest.c Next Metric …
… … …
D C 2
… … …
D B 3
… … …
D B 1
… … …
D D 

(D, 2)(D, 2)
Distance Vector (Loops)
C
1 1
BA D
1
… … …
D B 3
… … …
D C 2
… … …
D B 3

(D,2)
(D,4)
(D,3)
(D,5)
(D,2)
(D,4)
Distance Vector (Count to Infinity)
C
1 1
BA D
1
… … …
D B 3, 5, …
… … …
D B 3, 5, …
Dest.c Next Metric …
… … …
D C 2, 4, 6…

Distance Vector
 DV not suited for ad-hoc networks!
 Loops
 Count to Infinity
 New Solution -> DSDV Protocol

Question
Which protocol is proposed to overcome loops
AODV
DSDV

DSDV

Question
Routing table information is ___________ to their
neighbors
Broadcast
Unicast

Broadcast

Question
If any link is broken, the metric is denoted by
Infinity
Odd number
Even Number

Infinity

DSDV Protocol
 DSDV is Destination Based
 No global view of topology

Question
DSDV is destination based
TRUE
FALSE

TRUE

DSDV Protocol
 DSDV is Proactive (Table Driven)
 Each node maintains routing information for all known
destinations
 Routing information must be updated periodically
 Traffic overhead even if there is no change in network topology
 Maintains routes which are never used

DSDV Protocol
 Keep the simplicity of Distance Vector
 Guarantee Loop Freeness
 New Table Entry for Destination Sequence Number
 Allow fast reaction to topology changes
 Make immediate route advertisement on significant
changes in routing table
 but wait with advertising of unstable routes
(damping fluctuations)

DSDV (Table Entries)
 Sequence number originated from destination. Ensures
loop freeness.
 Install Time when entry was made (used to delete stale
entries from table)
 Stable Data Pointer to a table holding information on
how stable a route is. Used to damp fluctuations in
network.
Destination Next Metric Seq. Nr Install Time Stable Data
A A 0 A-550 001000 Ptr_A
B B 1 B-102 001200 Ptr_B
C B 3 C-588 001200 Ptr_C
D B 4 D-312 001200 Ptr_D

Question
What is the use of Install Time
To ensure loop freeness
To delete stale entries from the table

To delete stale entries from the table

DSDV (Route Advertisements)
 Advertise to each neighbor own routing information
 Destination Address
 Metric = Number of Hops to Destination
 Destination Sequence Number
 Rules to set sequence number information
 On each advertisement increase own destination sequence
number (use only even numbers)
 If a node is no more reachable (timeout) increase
sequence number of this node by 1 (odd sequence
number) and set metric = 

Question
What is Metric?
No of hops to source
No of hops to intermediate nodes
No of hops to destination

No of hops to destination

DSDV (Route Selection)
 Update information is compared to own routing
table
 1. Select route with higher destination sequence
number (This ensure to use always newest information
from destination)
 2. Select the route with better metric when sequence
numbers are equal.

DSDV (Tables)
C
Dest. Next Metric Seq
A A 1 A-550
B B 0 B-100
C C 2 C-588
A A 0 A-550
B B 1 B-100
C B 3 C-588
Dest. Next Metric Seq.
A B 3 A-550
B B 2 B-100
C C 0 C-588
BA 1 2

(A, 1, A-500)
(B, 0, B-102)
(C, 1, C-588)
(A, 1, A-500)
(B, 0, B-102)
(C, 1, C-588)
DSDV (Route Advertisement)
CBA
B increases Seq.Nr from 100 -> 102
B broadcasts routing information
to Neighbors A, C including
destination sequence numbers
A A 0 A-550
B B 1 B-102
C B 2 C-588
A A 1 A-550
B B 0 B-102
C C 1 C-588
A B 2 A-550
B B 1 B-102
C C 0 C-588
1 1

DSDV (Respond to Topology Changes)
 Immediate advertisements
 Information on new Routes, broken Links, metric
change is immediately propagated to neighbors.
 Full/Incremental Update:
 Full Update: Send all routing information from own
table.
 Incremental Update: Send only entries that has
changed. (Make it fit into one single packet)

(D, 0, D-000)
DSDV (New Node)
CBA D
A A 0 A-550
B B 1 B-104
C B 2 C-590
A A 1 A-550
B B 0 B-104
C C 1 C-590
A B 2 A-550
B B 1 B-104
C C 0 C-590
D D 1 D-000
1. D broadcast for first time
Send Sequence number D-000
2. Insert entry for D with
sequence number D-000
Then immediately broadcast own
table

(A, 2, A-550)
(B, 1, B-102)
(C, 0, C-592)
(D, 1, D-000)
(A, 2, A-550)
(B, 1, B-102)
(C, 0, C-592)
(D, 1, D-000)
DSDV (New Node cont.)
CBA D
A A 1 A-550
B B 0 B-102
C C 1 C-592
D C 2 D-000
A A 0 A-550
B B 1 B-104
C B 2 C-590
A B 2 A-550
B B 1 B-102
C C 0 C-592
D D 1 D-000
………
………
3. C increases its sequence
number to C-592 then
broadcasts its new table.4. B gets this new information
and updates its table…….

(D, 2, D-100)(D, 2, D-100)
DSDV (no loops, no count to infinity)
CBA D
Dest.c Next Metric Seq.
… … …
D C 2 D-100
… … …
D B 3 D-100
… … …
D D  D-101
1. Node C detects broken Link:
-> Increase Seq. Nr. by 1
(only case where not the destination
sets the sequence number -> odd
number)
2. B does its broadcast
-> no affect on C (C knows that B
has stale information because C has
higher seq. number for destination D)
-> no loop -> no count to infinity

(D, , D-101)(D, , D-101)
DSDV (Immediate Advertisement)
CBA D
… … …
D C 3 D-100
… … …
D B 4 D-100
… … …
D B 1 D-100
… … …
D D 1 D-100
D D  D-101
1. Node C detects broken Link:
-> Increase Seq. Nr. by 1
(only case where not the destination
sets the sequence number -> odd
number)
3. Immediate propagation
B to A:
(update information has higher
Seq. Nr. -> replace table entry)
2. Immediate propagation
C to B:
(update information has higher
Seq. Nr. -> replace table entry)
… … … ...
D C 2 D-100
D C  D-101
… … … ...
D B 3 D-100
D B  D-101

DSDV (Problem of Fluctuations)
What are Fluctuations
 Entry for D in A: [D, Q, 14, D-100]
 D makes Broadcast with Seq. Nr. D-102
 A receives from Q Update (D, 14, D-102)
-> Entry for D in A: [D, Q, 14, D-102]
A must propagate this route immediately.
 A receives from P Update (D, 15, D-102)
-> Entry for D in A: [D, P, 15, D-102]
A must propagate this route immediately.
This can happen every time D or any other node does its
broadcast and lead to unnecessary route advertisements
in the network, so called fluctuations.
A
D
QP
10 Hops11 Hops
(D,0,D-102)

DSDV (Damping Fluctuations)
A
D
QP
10 Hops11 Hops
How to damp fluctuations
 Record last and avg. Settling Time of every Route in
a separate table. (Stable Data)
Settling Time = Time between arrival of first route
and the best route with a given seq. nr.
 A still must update his routing table on the first
arrival of a route with a newer seq. nr., but he can
wait to advertising it. Time to wait is proposed to be
2*(avg. Settling Time).
 Like this fluctuations in larger networks can be
damped to avoid unececarry adverdisment, thus
saving bandwith.

Summary
 Advantages
 Simple (almost like Distance Vector)
 Loop free through destination seq. numbers
 No latency caused by route discovery
 Disadvantages
 No sleeping nodes
 Overhead: most routing information never used

DSDV Protocols by Mr.Darwin Nesakumar A, AP/ECE, R.M.K.Engineering College

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