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A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks

A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks. By Lei Chen. What is Ad Hoc Wireless Network?. A collection of mobile nodes that are dynamically and aribitrarily located Infrastructureless mobile network Each node must act as a router

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A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks

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  1. A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks By Lei Chen

  2. What is Ad Hoc Wireless Network? • A collection of mobile nodes that are dynamically and aribitrarily located • Infrastructureless mobile network • Each node must act as a router • Most nodes will not wish to perform any administrative actions to set up such a network.

  3. Routing Protocols Ad - Hoc Routing Protocols Source - initiated Table Driven On - Demand Driven DSDV WRP AODV DSR TORA ABR CGSR SSR

  4. Table Driven Routing Protocol • Attempt to maintain consistent, up-to-date routing information from each node to every other node in the network • The number of necessary routing-related tables and methods of broadcasting are different

  5. Destination-Sequenced Distance-Vector Routing (DSDV) • A table based protocol • Every node maintains a complete table listed all possible destination • Each entry of the table marked with a sequence number assigned by the destination node

  6. DSDV (continue) Every node keep a route table <Destination-address, Metric, Sequence-number> for every possible destination

  7. Source-initiated On-demand Routing Protocol • Initiates a route discovery process within the network, when a node requires a route to a destination • Maintain by some form of route maintenance procedure until either the destination becomes inaccessible or the route is not desired

  8. Ad-hoc On-demand Distance Vector Routing (AODV) • An on demand routing protocol • Description AODV uses a broadcast route discovery mechanism as is also used in DSR. Instead of source routing, however, AODV relies on dynamically establishing route table entries at intermediate nodes

  9. AODV (continue) • A mobile node maintains a table entry for each destination of interest. Route table entry contains the following information: • Destination • Next Hop • Number of hops (metric) • Sequence number for the destination • Active neighbors for this route • Expiration time for the route table entry • Source node sends a RREQ packet • Intermediate nodes forward it to destination • Destination node distinguish the RREQ by <broadcastID, source-address>, and sends back RREP when receives the first RREQ packet.

  10. Dynamic Source Routing (DSR) • An on-demand routing protocol • Description • A source flood REQUEST if it has data to send but no route to its destination is know • When the destination get the REQUEST, it sends a REPLY to the source via the recorded route • Use source routing instead of hop-to-hop routing

  11. DSR continue • Every node has a cache which contain the complete path information to the destination node • If the source node can’t find the destination node in its cache, it will initial a route discovery • The source node sends the RREQ packet which is <source-address, destination-address, route-record, request-id> • Intermediate node • If it is the destination copy the head and send RREP • If it is already listed in the route-record, discard it • Else, it forward the RREQ, and add itself in the route-record

  12. Table-Driven vs On-Demand Routing • Table-Driven • is similar to the connectionless approach of forwarding packets, with no regard to when and how frequent such routes are desired • A routing is always available, regardless whether or not it is needed • On-Demand • Has to wait until a desired route is discovered.

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