8/7/20151 Mobile Ad hoc Networks COE 549 Routing Protocols I Tarek Sheltami KFUPM CCSE COE .

8/7/20151 Mobile Ad hoc Networks COE 549 Routing Protocols I Tarek Sheltami KFUPM CCSE COE http://faculty.kfupm.edu.sa/coe/tarek/coe549.htm

Outline 8/7/20152 Routing Algorithms Classifications Proactive Routing: Table Driven Protocols Cluster-based Protocols

15/4/20033 Routing Algorithm Classifications Routing Algorithms Proactive Reactive Table Driven Cluster-based On-Demand Hybrid Cluster-based

Table Driven Protocols 8/7/20154 Distance Vector Protocols such as: Wireless Routing Protocol (WRP) [MUR96] Destination Sequenced Distance Vector (DSDV) routing protocol [PER94] Least Resistance Routing (LRR) [PUR93] The protocol by Lin and Liu [LIN99]. Link State Protocols such as: Global State Routing (GSR) [CHE98] Fisheye State Routing (FSR) [PEI00a] Adaptive Link-State Protocol (ALP) [PEI00a] Source Tree Adaptive Routing (STAR) [ACE99] Optimized Link State Routing (OLSR) protocol [SHE03b] Landmark Ad Hoc Routing (LANMAR) [PEI00b] However the most prominent protocol is DSDV

Table Driven Protocols 8/7/20155 Try to match the link state and distance vector ideas to the wireless environment Each node only needs to know the next hop to the destination, and how many hops away the destination is: This information stored in each node is often arranged in a table, hence the term table-driven routing Such algorithm are often called distance vector algorithms, because nodes exchange vectors of their known distances to all other nodes An example is the Bellman-Ford algorithm, one of the first ones to be used for routing in the Internet

Bellman-Ford Algorithm 8/7/20156 Consider a collection of nodes, connected over bi-directional wired links of given delays. We want to find the fastest route from each node to any other node. An example network: Initially, each node knows the distances to its direct neighbors, and stores them to its routing table. Nodes other than their direct neighbors are assumed to be at an infinite distance. Then, nodes start exchanging their routing tables.

Stage 1 8/7/20157

Stage 2 8/7/20158

Stage 3 8/7/20159

Table Driven Protocols 8/7/201510 As the number of nodes n increases, the routing overhead increases very fast, like O(n 2 ). When the topology changes, routing loops may form:

Destination Sequenced Distance Vector (DSDV) 8/7/201511 One of the earlier ad hoc routing protocols developed Its advantage over traditional distance vector protocols is that it guarantees loop freedom Each routing table, at each node, contains a list of the addresses of every other node in the network Along with each nodes address, the table contains the address of the next hop for a packet to take in order to reach the node In addition to the destination address and next hop address, routing tables maintain the route metric and the route sequence number.

Destination Sequenced Distance Vector (DSDV).. 8/7/201512 The update packet starts out with a metric of one The neighbors will increment this metric and then retransmit the update packet. This process repeats itself until every node in the network has received a copy of the update packet with a corresponding metric If a node receives duplicate update packets, the node will only pay attention to the update packet with the smallest metric and ignore the rest

Destination Sequenced Distance Vector (DSDV).. 8/7/201513 To distinguish stale update packets from valid ones, the original node tags each update packet with a sequence number The sequence number is a monotonically increasing number, which uniquely identifies each update packet from a given node If a node receives an update packet from another node, the sequence number must be greater than the sequence number already in the routing table; otherwise the update packet is stale and ignored

15/4/200314 DSDV Routing Protocol

15/4/200315 DSDV Routing Protocol

15/4/200316 Disadvantages of DSDV Protocol Routing is achieved by using routing tables maintained by each node The bulk of the complexity in generating and maintaining these routing tables If the topological changes are very frequent, incremental updates will grow in size This overhead is DSDVs main weakness, as Broch et al. [BRO98] found in their simulations of 50- node networks

Virtual Base Station (VBS) All nodes are eligible to become clusterhead / VBS Each node is at one hop from its clusterhead Clusterhead / VBS is selected based on the smallest ID Gateways / Boarder Mobile Terminals (BMTs) Clsuterheads and Gateways form the virtual backbone of the network

VBS.. Every MT has an ID number, sequence number and my_VBS variable Every MT increases its sequence number after every change in its situation An MT my_VBS variable is set to the ID number of its VBS; however, if that MT is itself a VBS, then the my_VBS variable will be set to 0, otherwise it will be set to 1, indicating that it is a VBS of itself

VBS Illustrated

VBS Illustrated..

CGSR infrastructure Creation CGSR uses the Least Cluster Change (LCC) clustering algorithm No clusterheads in the same transmission range Each Cluster has a different code to eliminate the interference, typically the suggest 4 Walsh codes

CGSR Illustrated

CGSR Illustrated..

Simulation Results

Simulation Results..

15/4/200332 Range of node #1 Routing in VBS Some issues about pure Cluster-based Routing (VBS)

15/4/200333 Some issues about pure Cluster-based Routing (VBS)

15/4/200334 Routing in VBS Some issues about pure Cluster-based Routing (VBS)

Drawback of VBS 8/7/201535 All the nodes require the aid of their VBS(s) all the time, so this results a very high MAC contention on the VBSs the periodic hello message updates are not efficiently utilized by MTs (other than VBSs and BMTs) The power of the nodes with small IDs drain down much faster than that with large IDs

36 Nodes Classifications: myCH = 0 Clusterhead myCH = -1 Free node myCH > 0 Zone_MT WEAC Infrastructure Creation Protocol 4/29/2008 An MT is eligible to be a clusterhead and willing to accept other MTs to be under its supervision if these MTs have a lower EL An MT ignores any merge request messages that are sent to it by other MTs. However, if the MT is serving as a clusterhead, it will remain a clusterhead If an MT is serving as a clusterhead, it sets its warningThreshold flag to true, informing its zone_MTs to look for another clusterhead, nonetheless, they can remain with it till its BPL drains down to THRESHOLD_3 An MT ignores any merge request messages and will send iAmNoLongerYourCH message to all the nodes under its supervision, if it was serving other nodes

List of MTs 5 WEAC Infrastructure Creation Protocol.. Merge REQ Merge Accpt. myCH = 20myCH = -1 myCH = 0 20 5 BPL > THRESHOLD_1 BPL < THRESHOLD_1 An MT sends a merge-request message to another MT if the latter has a higher energy level and it should be > Threshold_1 8/7/201537

WEAC Infrastructure Creation Protocol.. 8/7/201538

8/7/201539 WEAC Infrastructure Creation Protocol..

8/7/201540 WEAC Infrastructure Creation Protocol..

Broadcasting The Neighbor List 8/7/201541

Selecting Gateways The least number of neighbors method The highest energy level method The Gateway Selection Algorithm 8/7/201542

The Gateway Selection Algorithm 1.if(there is more than one access to DEST){ 2. Select the MT with EL > THRESHOLD_2; 3. if(more than one with EL THRESHOLD_2){ 4. getTheLeastNumberOfNeighbors(); 5. select the one with the least number of neighbors; 6. } 7. elseif(MTs EL < THRESHOLD_2) 8. choose the one with the highest EL(); } 8/7/201543

Table update for zone_MTs 1.if(myCH > 0) 2. if(DEST my neighbor || DEST my neighbors neighbor){ 3. set this neighbor as the next hop; 4. if(more than one neighbor to the DEST) 5. run Gateway Selection Algorithm(), 6. } 7. else 8. set myCH as the next hop 8/7/201544

Table update for clusterheads and free_MTs 1.if(myCH 0) 2. update routing table according to the received tables 3. if(the DEST my neighbor || my neighbor s neighbor){ 4. set this neighbor as the next hop 5. if(more than one neighbor to the DEST) 6. run Gateway Selection Algorithm(); } 7. else if(available route to the DEST) 8. keep the current route till the next update; 9. else 10. set the DEST to null; 8/7/201545

Simulation Results 8/7/201546

Simulation Results.. 8/7/201547

8/7/20151 Mobile Ad hoc Networks COE 549 Routing Protocols I Tarek Sheltami KFUPM CCSE COE .

Documents

routing protocols

routing tables

routing overhead

routing loops

routing lanmar pei00b

term tabledriven routing

dsdv slide

link state protocols