1. Some Typical Routing Protocols in Mobile Ad Hoc Networks
Advanced Networking Course
Mehdi Sadri
Jamshid Esmaeilnejad
Spring 2012

2. Classification

3. Zone Based Hierarchical Routing Protocols

4. Zone Based Hierarchical Routing Protocols
The Zone Routing Protocol (ZRP)
The Hybrid Ad hoc Routing Protocol (HARP)
The Zone-based Hierarchical Link State Routing (ZHLS)

5. The Zone Routing Protocol (ZRP)
The First hybrid routing protocol.
HRP motivations:
Reduce control overhead of proactive routing protocols
Decrease latency caused by route search operations in reactive approaches

6. The Zone Routing Protocol (ZRP)
Partitioning into zones....
Network is divided into routing zones.
Given node N: nodes within hop distance at most d => N's routing zone.
Peripheral nodes: nodes which are exactly d hops away from N.

7. The Zone Routing Protocol (ZRP)
Different routing approaches are exploited.
Inter-zone : Inter-zone Routing Protocol (IERP)
Intra-zone : Intra-zone Routing Protocol (IARP)

8. The Zone Routing Protocol (ZRP)
Routing Example ...

9. The Zone Routing Protocol (ZRP)
Routing Example ...

10. The Zone Routing Protocol (ZRP)
Routing Example ...

11. The Hybrid Ad hoc Routing Protocol (HARP)
Similar to ZRP : different routing approaches use in different levels of zone hierarchy (Intra and Inter zone routing).
Similar to ZRP :
Intra-zone routing : existing proactive scheme
Inter-zone routing : existing reactive scheme

12. The Hybrid Ad hoc Routing Protocol (HARP)
Distributed Dynamic Routing (DDR)
Nodes periodically exchange topology messages.
A forest is constructed from the network topology in a distributed way.
Each tree in the forest becomes a zone.

13. The Hybrid Ad hoc Routing Protocol (HARP)
Gateway nodes ...
Nodes which are in different zones but are within the direct transmission range are defined as gateway nodes.

14. The Hybrid Ad hoc Routing Protocol (HARP)
Distributed Dynamic Routing (DDR)

15. The Zone-based Hierarchical Link State routing (ZHLS)
Another hybrid routing protocol
Nodes are assumed to know their physical location with assistance from a location system like GPS
Network is partitioned into non-overlapping zones based on geographical information.

16. The Zone-based Hierarchical Link State routing (ZHLS)
Hierarchical addressing structure which contains node ID and zone ID
Two-level network topology
node level : node level LSP (broadcasted in each zone)
zone level : zone level LSP (broadcasted by zone gateways when a virtual link is broken or created)

17. The Zone-based Hierarchical Link State routing (ZHLS)
A wants to send a packet to B.
if B is in the same zone, A knows B
if not, the gateways of A's zone ask neighbors.
Each node which receives a location request checks its intra-zone routing table and returns the address or forwards to other neighbors.

18. The Zone-based Hierarchical Link State routing (ZHLS)
Routing (Example)

20. Cluster-based routing protocols
The Clusterhead Gateway Switch Routing (CGSR)
The Hierarchical State Routing
Cluster Based Routing Protocol (CBRP)
Comparison of cluster based hierarchical routing protocols presented

21. Clusterhead Gateway Switch Routing (CGSR)
CGSR is a hierarchical routing protocol.
Cluster Structure
Provides Effective Membership and Traffic Management.
Performance Improvement
Similar Proactive routing mechanism as DSDV (Destination-Sequenced Distance-Vector Routing (DSDV) is a table-driven routing scheme for ad hoc mobile networks based on the Bellman-Ford algorithm.)
Routing Information Collection, Update and Distribution +
Cluster Construction and Cluster Head Selection

22. CGSR (cont.) Mobile nodes are aggregated into clusters.
A clusterhead is elected for each cluster.
Gateway nodes are responsible for communication between two or more clusterhead.
Nodes maintain a cluster member table that maps each node to its respective clusterhead.

23. CGSR (cont.) A node broadcasts its cluster member table periodically.
After receiving broadcasts from other nodes, a node uses the DSDV algorithm to update its cluster member table.
Each node maintains a routing table that determines the next hop to reach other clusters.
Dynamic Network
Performance Degradation
Frequent elections of a Clusterhead.
Least Cluster Change (LCC) algorithm
Two clusterheads merging into one.
A node being out of the coverage of all current clusters.

24. CGSR (cont.) Forwarding a Packet
Node first checks both its cluster member table and routing table.
Tries to find the nearest clusterhead along the routing path.

25. The Hierarchical State Routing (HSR)
A multi-level cluster- based hierarchical routing protocol.
The clusterheads of low level clusters again organize themselves into upper level clusters, and so on.

26. HSR (cont.)
Inside a cluster, nodes broadcast their link state information to all others.
The clusterhead summarizes link state information of its cluster and sends the information to its neighboring clusterheads.
Nodes in upper level hierarchical clusters flood the network topology information they have obtained to the nodes in the lower level clusters.
A hierarchical address is assigned to every node. Hierarchical address reflects the network topology and provides enough information for packet deliveries in the network.

27. HSR (cont.)
Nodes are also partitioned into logical subnetworks corresponding to different user groups.
Each node has a logical address in the form of <subnet, host>.
For each subnetwork, there is a location management server (LMS) which records the logical addresses of all nodes in the subnetwork.
LMSs advertise their hierarchical addresses to the top level of hierarchical clusters.
The routing information,which contains LMSs’ hierarchical addresses, is sent down to all LMSs.

28. HSR (cont.)
Source node only knows the logical address of the destination node.
The source node first checks its LMS and tries to find the hierarchical address of the destination’s LMS.
The source sends the packet to the destination’s LMS.
The destination’s LMS forwards the packet to the destination.
Once the source knows the hierarchical address of the destination, it sends packets directly to the destination without consulting LMSs.

29. HSR (cont.)
In HSR, logical addresses reflect the group property of mobile nodes and hierarchical addresses reflect their physical locations.
Combining these addressing schemes can improve adaptability of the routing algorithm.

30. Cluster Based Routing Protocol (CBRP)
The clustering algorithm is performed when a node joins the network.
Node is "undecided" When joins
Sets a timer and broadcasts a Hello message.
A clusterhead receives the Hello message.
Replies with a triggered Hello message.
The “undecided” node changes its state to "member" state.
If the “undecided” node does not receive a message from a clusterhead before the local timer generates a timeout, it makes itself a clusterhead.

31. CBRP (cont.)
In CBRP, every node maintains a neighbor table in which it stores the information about link states(uni- directional or bi-directional) and the state of its neighbors.
A clusterhead keeps information of its neighboring clusters, which includes the clusterheads of neighboring clusters and gateway nodes connecting it to neighboring clusters.

32. CBRP (cont.)
If a source node wants to send a packet but has no active route which can be used, it floods route request to clusterhead of its own and all neighboring clusters.
If a clusterhead receives a request it has seen before, it discards the request.
Otherwise, the clusterhead checks if the destination of the request is in its cluster.
The clusterhead sends the request to the destination.
else it floods the request to its neighboring clusterheads.

33. CBRP (cont.)
An optimization method exploited by CBRP is local repair. Whenever a node has a packet to forward and the next hop is not reachable, it checks the routing information contained in the packet. If the next hop or the hop after next hop in the route is reachable through one of its neighbors, the packet is forwarded through the new route.

34. Comparison of cluster based hierarchical routing protocols presented
Different clustering algorithms
Different clusterhead election algorithms
HSR:
Hierarchical addressing is used and the network may have a recursive multi-level cluster structure.
A location management mechanism is used to map the logical address to the physical address.
CGSR:
Every node keeps routing information for other nodes in both the cluster member table and the routing table.
CBRP:
A clusterhead maintains information about its members and its neighboring clusterheads.
Exploits the source routing scheme and the addresses of clusterheads along a route are recorded in the data packets.

35. Core-node based routing protocols

36. Landmark Ad hoc Routing (LANMAR)
A modification Fisheye State Routing (FSR)
Aims to get better scalability
Belongs to non-uniform category

37. Landmark Ad hoc Routing (LANMAR)
Nodes are divided into logical predefined subsets : w.r.t. moving patterns
Nodes in one subset are prone to move as a group
One node becomes Landmark of the subset and is responsible to keep track of the subset

38. Landmark Ad hoc Routing (LANMAR)
Each node maintains :
topology information of its neighbors
all the landmark nodes
Similar to FSR, periodically nodes exchange:
Topology information to neighbors
the distance vector of landmark nodes

39. Landmark Ad hoc Routing (LANMAR)
Source wants to send message to destination
if it is in the same subnet its address exists in source routing table
if not,
dest. subnet is identified from dest. address
message is forwarded toward dest. landmark uysing the distance vector.

40. Landmark Ad hoc Routing (LANMAR)
Snapshot ...

41. The Core-Extraction Distributed Ad Hoc Routing (CEDAR)
Another non-uniform routing protocol
A subset of nodes are identified as core nodes
A distributed algorithm to select core nodes
The number of core nodes is kept small

42. The Core-Extraction Distributed Ad Hoc Routing (CEDAR)
Choosing core nodes : guarantees
each node must be adjacent to at least one core node => this core becomes its dominator
each core node is at least 3 hops away from another core node
Neighboring nodes periodically exchange link state information to choose the cores
Every core node determines paths to core node nearby using localized broadcasts

43. The Core-Extraction Distributed Ad Hoc Routing (CEDAR)
Link state information propagation ...
It is done only between core nodes
Propagation distance is a function of link stability and bandwidth
Result : Core nodes know
local link state information
the state of stable and high bandwidth nodes far away

44. The Core-Extraction Distributed Ad Hoc Routing (CEDAR)
S wants to send packet to D
S informs its dominator (SD)
SD finds a route in core network to D's dominator (DD) - DSR like discovery process
Core nodes involved in the path build a route from S to D

45. The Optimized Link State Routing protocol (OLSR)
Proactive & Table-driven
Link State Routing
Each node expands a spanning tree
Each node can obtain the whole network topology
Utilizes a technique to reduce message flooding
MultiPoint Relaying (MPR)

46. OLSR (cont.) Each node periodically floods status of its links
Each node re-broadcasts link state information received from its neighbors
Each node keeps track of link state information received from other nodes
Each node uses above information to determine next hope to each destination
Only selected neighbors (MultiPoint Relays, MPRs) retransmit messages
Select MPRs such that they cover all 2hop neighbors
2-hop neighbors taken from neighbors' HELLO messages

47. OLSR (cont.)

48. Comparison of CEDAR, OLSR and LANMAR
In a core-node based routing protocol, the core-node extraction method is a key component.
CEDAR,OLSR and LANMAR apply totally different approaches for core node extraction purpose.
In LANMAR, the landmark nodes are application related and pre-defined according to their mobility pattern.
In CEDAR, a minimal (or nearly minimal) set of core nodes is selected to cover the network according to a certain optimization algorithm.
A node selects its MPR independently in OLSR.

49. References
[1] Z. J. Haas. The Zone Routing Protocol (ZRP) for ad hoc networks, Internet Draft, Nov
[2] M. Joa-Ng and I-Tai Lu, A peer-to-peer zone-based two-level link state routing for mobile ad hoc networks,IEEE on Selected Areas in
Communications, vol. 17, no. 8, pp , 1999.
[3] Navid Nikaein, Christian Bonnet and Neda Nikaein, HARP - Hybrid Ad Hoc Routing Protocol, in proceeding of IST 2001: International Symposium on Telecommunications, Iran/Tehran 2001.
[4] Mingliang Jiang, Jinyang Li and Y. C. Tay. Cluster Based Routing Protocol (CBRP), Internet draft,draft-ietf-manet-cbrp-spec-01.txt.
[5] C. C. Chiang, T. C. Tsai, W. Liu and M. Gerla, Routing in clustered multihop, mobile wireless networks with fading channel, The Next Millennium, The IEEE SICON, 1997.
[6] P. Jacquet, P. Muhlethaler, and A. Qayyum, Optimized Link State Routing Protocol, IETF MANET, Internet draft, 1998.

50. References
[7] Z. J. Haas and M.R Pearlman, The Zone Routing Protocol (ZRP) for ad hoc networks. IETF Internet draft , August 1998.
[8] P. Sinha, R. Sivakumar and V. Bharghaven, CEDAR: a Core-Extraction Distributed Ad hoc Routing algorithm. IEEE INFOCOM, March 1999.
[9] A. Iwata, C.-C. Chiang, G. Pei, M. Gerla, and T.-W. Chen, Scalable routing strategies for ad hoc wireless networks. IEEE Journal on Selected Areas in Communications, Special Issue on Ad-Hoc Networks, August 1999, p1369- p1379.
[10] G. Pei, M. Gerla, and X. Hong, LANMAR: Landmark routing for large scale wireless ad hoc networks with group mobility. In Proceedings of the ACM Symposium on Mobile Ad Hoc Networking and Computing (MOBIHOC), pages 11-18, 2000.