Transcript seminar of NITESH

Routing protocols in
Mobile Ad Hoc Network
Presented By :Nitesh Jain
Date:-26/10/2005
SCHOOL OF INFORMATION TECHNOLOGY
INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR
KHARAGPUR
Types of Wireless Networks
 Infrastructure based(Cellular Network).
 Infrastructureless Network(Mobile Ad hoc
NETwork) (MANET).
Characteristics of an Ad-hoc network
 Collection of mobile nodes forming a temporary
network
 Network topology changes frequently and
unpredictably
 No centralized administration or standard
support services
 Host is also function as router
Why is Routing Different in Ad Hoc ???
 Host mobility
• Dynamic topology
• link failure/repair due to mobility
 Distributed Environment
 Bandwidth constrained
 Energy constrained
Categorization of Ad-Hoc Routing Protocols
Table Driven Routing Protocol
 Proactive.
 Each node maintains one or more tables
containing routing information to every other
node in the network.
 Tables need to be consistent and up-to-date
view of the network.
 Updates propagate through the network
Source Initiated On demand routing protocol
 Reactive.
 on-demand style: create routes only when it is
desired by the source node
 When a node requires a route to a destination,
it initiates a route discovery process
 Route is maintained until destination becomes
unreachable, or source no longer is interested
in destination.
Table Driven Routing Protocol
Destination-Sequenced Distance Vector Protocol
(DSDV)


Basic Routing Protocol
Based on Bellman ford routing algorithm with some
improvement

Each node maintains a list of all destinations and
number of hops to each destination.


Each entry is marked with a sequence number.
Periodically send table to all neighbors to maintain
topology
• Two ways to update neighbors:
– Full dump
– Incremental update
Example of DSDV
A’s Routing Table Before Change
Destination
Next Hop
Distance
Sequence Number
A
A
0
S205_A
B
B
1
S334_B
C
C
1
S198_C
D
D
1
S567_D
E
D
2
S767_E
F
D
2
S45_F
A’s Routing Table After Change
Destination
Next Hop
Distance
Sequence Number
A
A
0
S304_A
B
D
3
S424_B
C
C
1
S297_C
D
D
1
S687_D
E
D
2
S868_E
F
D
2
S164_F
Clusterhead Gateway Switch Routing
(CGSR)
 Similar to DSDV
 Based on concept of clusters and cluster heads
 Routing is done via the cluster heads and
gateways
 A routing table among cluster heads are
maintained
Example of CGSR
Data forwarding steps:
•from cluster head to
cluster head
–in a hierarchical manner
•then from cluster head to
cluster members
•between two cluster heads,
gateways are used to forward
the packets
Source Initiated On demand
routing protocol
Ad hoc On-demand Distance Vector Routing
(AODV)
 Pure on-demand protocol
 Node does not need to maintain knowledge of another
node unless it communicates with it
 AODV includes route discovery and route maintenance.
 AODV minimizes the number of broadcasts by creating
routes on-demand
 AODV uses only symmetric links because the route reply
packet follows the reverse path of route request packet
 AODV uses hello messages to know its neighbors and
to ensure symmetric links
Path discovery
 In the path discovery
(RREQ) phase, source
broadcasts RREQ message.
 Intermediate nodes record
in their route tables the
address of neighbor from
which RREQ is received to
establish a reverse path.
 When RREQ reaches
destination or an
intermediate node
responds by unicasting a
route reply (RREP) back to
neighbor.
Path maintenance
 If source node moves, reestablish the path.
 If destination or intermediate node moves,
send link failure notification message to each
of its active upstream.
 Then reinitiate path discovery .
Dynamic Source Routing Protocol
(DSR)
 on-demand
 A node maintains route cache containing the
routes it knows
 Two main phases
• Route discovery
• Route maintenance
 Basic Operation is similar to AODV.
 Main difference
• To use routing cache for link failure.
• When route discovery phase, node send route
request message with its own address.
Example of DSR
Hybrid Routing Protocols
Zone Routing Protocol
 Hybrid of table-driven and on-demand!!
 From each node, there is a concept of “zone”.
• Within each zone, the routing is performed in a
table-driven manner (proactive).
• However, a node does not try to keep global
routing information.
 For inter-zone routing, on-demand routing is
used.
Example of ZPR
 Three types of nodes:
• Border Nodes
• Peripherals Nodes
• Interior Nodes
Comparison
Parameters
On Demand
Table Driven
Availability of routing
information
Available when
needed
Always available regardless
of need
Routing philosophy
Flat
Mostly flat, except for
CGSR
Periodic route updates
Not required
Required
Coping with mobility
Use localized route
discovery
Inform other nodes to achie
ve a consistent routing
table
Signaling traffic generated
Grows with
increasing mobility
Greater than that of on
demand routing
References
 Elizabeth M. Royer, Chai-Keong Toh, A Review of Current Routing Prot
ocols for Ad Hoc Mobile Wireless Networks,Proc. IEEE,1999.
 David B. Johnson, " Routing in Ad hoc Networks of Mobile Hosts", Proc
IEEE Workshop on Mobile Computing Systems and Applications.
 Nicklas Beijar “Zone Routing Protocol “.
 www.cse.wustl.edu/~jain/cis788-99/adhoc_routing/
 http://www.comp.brad.ac.uk/~sburuha1/index.htm
 www.computingunplugged.com/ issues/issue200407/0000132600
1.html
 http://www.ietf.org/rfc/rfc3561.txt
THANKYOU
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