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Overview of Ad Hoc Routing Protocols. Overview 1.

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Presentation on theme: "Overview of Ad Hoc Routing Protocols. Overview 1."— Presentation transcript:

1 Overview of Ad Hoc Routing Protocols

2 Overview 1.

3 Overview

4 Table-Driven Approaches Protocols require each node to maintain one or more table to store routing information, and they respond to changes in network topology by propagating route updates throughout the network to maintain a consistent network view.

5 Distance Vector Routing Algorithm 1/2

6 Distance Vector Routing Algorithm 2/2 Count-to-infinite

7 Destination Sequenced Distance Vector (DSDV) 1/2 Introduction Table-Driven routing protocol Based on the classical distributed Bellman-Ford Algorithm. Using the Sequence Numbering System to avoid the routing loop in a mobile network of routers Two types of route update packets -Full dump -Incremental packets

8 Destination Sequenced Distance Vector (DSDV) 2/2 Routing New route broadcasts will contain the address of the destination node, the number of hops to reach the destination, the sequence number of the information received regarding the destination In the event that two updates have the same sequence number, the route with the smaller hop count is used.

9 Cluster Switch Gateway Routing (CSGR) 1/3 Introduction Mobile nodes are grouped into clusters and each cluster has a cluster head. CSGR modifies DSDV by using a hierarchical cluster- head-to-gateway routing approach to route traffic from source to destination.

10 Cluster Switch Gateway Routing (CSGR) 2/3 Routing Gateway nodes are nodes that are within communication range of two or more cluster. Each node must keep a Cluster member table and Routing table The cluster member tables are broadcast periodically by each node using the DSDV protocol. To avoid invoking cluster head reselection every time the cluster membership changes, a least cluster change (LCC) algorithm is introduced.

11 Cluster Switch Gateway Routing (CSGR) 3/3

12 Wireless Routing Protocol (WRP) Introduction WRP Belongs to the class of path-finding algorithm Avoid the count-to-infinity problem WRP must maintain four tables (a) Distance table (b) Routing table (c) Link-cost table (d) Message retransmission list table The update message contains a list of updates ( the destination, the distance to destination, the predecessor of the destination)

13 Source-Initiated On-Demand Approaches This type of routing creates routes only when desired by the source node. When a node requires a route to a destination, it initiates a route discovery process within the network.

14 Ad Hoc On-Demand Distance Vector Routing (AODV) 1/5 Introduction AODV is an improvement on DSDV Nodes that are not on a selected path do not maintain routing information or participate in routing table exchanges.

15 Ad Hoc On-Demand Distance Vector Routing (AODV) 2/5 Routing Protocol

16 Ad Hoc On-Demand Distance Vector Routing (AODV) 3/5

17 Ad Hoc On-Demand Distance Vector Routing (AODV) 4/5 Route Request (RREQ) Route Reply (RREP) AODV uses destination sequence numbers to ensure that all routes are loop-free and contain the most recent route information

18 Ad Hoc On-Demand Distance Vector Routing (AODV) 5/5 If a source node moves, it has to reinitiate the route discovery protocol to find a new route to the destination If a node along the route moves, its upstream neighbor notices the move and propagates a link failure notification message to each of its active upstream neighbors to inform them of the erasure of that part of the route.

19 Dynamic Source Routing (DSR) 1/3 Based on the concept of source routing Consist of two major phases -Route Discovery -Route Maintenance Route Discovery If a mobile node has an unexpired route to the destination This route request message contain destination address, source node’s address, a unique identification number Use the route Broadcasting a route request packet YES NO

20 Dynamic Source Routing (DSR) 2/3 Each node receiving the packet checks whether it know of a route to the destination Figure5.4a Use the route Add node’s own address to the route record of the packet and then forwards the packet along its outgoing links YES NO

21 Dynamic Source Routing (DSR) 3/3 Route Reply When either the route request reaches the destination itself, or when it reach an intermediate node that contains in its route cache an unexpired route to the destination

22 Temporally Ordered Routing Algorithm (TORA) 1/3 Based on the concept of link reversal Key design concept of TORA is the localization of control messages to a very small set of nodes near the occurrence of a topological change The protocol performs three basic functions -(a) Route creation -(b) Route maintenance -(c) Route erasure

23 Temporally Ordered Routing Algorithm (TORA) 2/3 Route creation Height Directed Acyclic Graph (DAG)

24 Temporally Ordered Routing Algorithm (TORA) 3/3 Route maintenance The DAG route is broken and route maintenance is necessary to re- establish a DAG rooted at the same destination

25 Associativity Based Routing (ABR) 1/3 A route is selected based on associativity states of nodes For every beacon received, a node increments its associativity tick with respect to the node from which it received The three phases of ABR are -Route Discovery -Route Reconstruction -Route Deletion

26 Associativity Based Routing (ABR) 2/3 Route Discovery The route discovery phase is a broadcast query and await- reply (BQ-REPLY) cycle A node does not forward a BQ request more than once Each packet arriving at the destination will contain the associativity ticks of the nodes along the route from source to the destination Once a path has been chosen, the destination sends a REPLY packet back to the source along this path.

27 Associativity Based Routing (ABR) 3/3 Route Reconstruction Source node movement results in a new BQ-REPLY process because the routing protocol is source-initiated When the destination moves, the destination’s immediate upstream node erases its route A localized query (LQ [H]) process where H refers to the hop count from the upstream node to the destination, is initiated to determine if the node is still reachable

28 Signal Stability Routing (SSR) 1/5 SSR is a descendent of Associativity-Based Routing SSR selects routes based on the signal strength between nodes and on a node’s location stability SSR route selection criteria has the effect of choosing routes that have “stronger” connectivities. SSR can be divided into two cooperative protocols -(a) the Dynamic Routing Protocol (DRP) -(b) the Static Routing Protocol (SRP)

29 Signal Stability Routing (SSR) 2/5 Dynamic Routing Protocol (DRP) The DRP is responsible for the maintenance of the signal strength of neighboring nodes The signal strength may be recorded as either a strong or weak channel After updating all appropriate table entries, the DRP passes a received packet to the SRP

30 Signal Stability Routing (SSR) 3/5 Static Routing Protocol (SRP) The SRP passes the packet up the stack if it is the intended receiver. If not, it looks up the destination in the RT and forwards the packet. If no entry is found in the RT for the destination, a route- search process is initiated to find a route Route requests are propagated throughout the network, but are only forwarded to the next hop if they are received over strong channels and have not been previously processed

31 Signal Stability Routing (SSR) 4/5 The destination chooses the first arriving route-search packet to send back because it is most probable that the packet arriving over the shortest and/or least congested path The DRP then reverses the selected route and sends a route-reply message back to the initiator The DRP of the nodes along the path update their RTs accordingly

32 Signal Stability Routing (SSR) 5/5 The assumption made in SSR is that route search packets arriving at the destination might have chosen the path of strongest signal stability, as the packets are dropped at a node if they have arrived over a weak channel If there is no route-reply message received at the source within a special timeout period, the source changes the PREF field in the header to indicate that weak channels are as these may be the only links over which the packet can be propagated

33 Power-Aware Routing (PAR) 1/2 In Power-Aware Routing, battery life is taken as the routing metric. PAR advocates for -Minimizing the energy consumed per packet -Maximizing the time before the network is partitioned -Minimizing the variance in node power levels -Minimizing the cost per packet -Minimizing the maximium node cost

34 Power-Aware Routing (PAR) 2/2

35 Zone Routing Protocol (ZRP) 1/3 The Zone Routing Protocol is a hybrid protocol incorporating the merits of on-demand and proactive routing protocols. With this zone, a table-driven-based routing protocol is used If the destination node reside outside the source zone. An on-demand search-query routing method is used. ZRP itself has three sub-protocols - IARP - IERP - BRP

36 Zone Routing Protocol (ZRP) 2/3

37 Zone Routing Protocol (ZRP) 3/3 The proactive (table-driven) Intrazone Routing Protocol (IARP) Its main role is to ensure that each node within the zone has a consistent routing table that is up-to-date and reflects information on how to reach all other nodes in the zone. The reactive Interzone Routing Protocol (IERP) IERP relies on border nodes to perform on-demand routing to search for routing information to nodes reside its current zone. IERP uses the bordercast resolution protocol

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