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Threads: 923
Joined: Sep 2010
Presented By
Nitesh Jain
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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
Posts: 5,362
Threads: 2,998
Joined: Feb 2011
Presented By :-
Nitesh Jain
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Routing protocols in Mobile Ad Hoc Network
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
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
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 page 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 page 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