ROUTING IN MOBILE AD-HOC NETWORKS

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ROUTING IN MOBILE AD-HOC NETWORKS

• Le Nam Thang
• Wang Xun
• Sriram Krishnamoorthy

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Problem Definition

• Determination and management of routes between
  nodes in the adhoc network.

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Solution characteristics

• Different metrics to optimize
• Should address frequent changes in
• Topology
• Traffic Patterns, etc.
• Handle any system characteristics such as
  unidirectional links.
• Should address trade-off between latency in
  determining a route and the overhead of route
  management (control traffic and state).

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Routing metrics

• Route length (hops)
• Signal stability (SSR)
• Freshness of route (AODV)
• Association stability (ABR)

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Classification
Ad hoc routing protocols
Flat routing
Hierarchical routing
Geographical position Augmented routing
Proactive
Reactive
CGSR
HSR
Proactive
Reactive
AODV
DSR
LAR
DSDV
WRP
GPSR
DREAM
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Flat Routing

• Flat routing protocols assume a flat topology
• All nodes are equally involved in routing.

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Hierarchical Routing

• Hierarchical routing protocols choose some nodes
  which act as the backbone of the MANET.

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Geography Oriented Routing
Uses geographical information (say from GPS) in
routing.
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Proactive Routing Protocols

• Maintain data structures which indicate the path
  to be taken for each destination node (also
  called table-driven protocols).
• Keep the data structures up-to-date by periodic
  exchange of information.

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Proactive Routing Protocols
Destination Metric Next Hop
MH1 2 MH2
MH2 1 MH2
MH3 2 MH2
MH4 0 -
MH5 2 MH6
.
Table for node MH4
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Reactive Routing Protocols

• Determine a route to a destination only when a
  request for transmission to that node arrives
  (also called on-command or source-initiated
  protocols).
• Usually cache newly found routes to minimize the
  latency involved in route discovery.
• Involve three phases
• Route discovery
• Route maintenance
• Route erasure

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Reactive Routing Protocols
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Extensions

• Special routing protocols for specific
  situations
• Power-aware routing
• Security issues.
• Multicast
• QoS support

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Problems

• Making explicit the trade-off between latency and
  state to maintain.