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Routing Protocol Comparison
Josh Broch, David A. Maltz, David B. Johnson, Yih-Chun Hu, and Jorjeta Jetcheva.
A Performance Comparison of Multi-Hop Wireless Ad Hoc Network Routing Protocols.
In Proceedings of the Fourth Annual International Conference on Mobile Computing and Networking (MobiCom'98), ACM, Dallas,
TX, October 1998.
-Shaan Mahbubani
Overview
â—Ź Focus
â—Ź Protocols
â—Ź Simulation
â—Ź Paper Evaluation
â—Ź Discussion
Focus
● “infrastructureless networking”
â—Ź Ad hoc networks
â—Ź Multiple hops
â—Ź Routing protocols
â—Ź Performance comparison
Protocols
â—Ź Destination-Sequence Distance Vector
â—Ź Temporal-Ordered Routing Algorithm
â—Ź Dynamic Source Routing
â—Ź Ad Hoc On-Demand Distance Vector
Destination-Sequence Distance Vector
â—Ź Hop by hop Distance Vectorâ—Ź Bellman Fordâ—Ź Loop freedom
● Per node routing table– Destination– Next hop– Number of hops– Sequence number
Temporally Ordered Routing Algorithm
â—Ź Link reversalâ—Ź Minimize communicationâ—Ź Avoid overhead rather than shortest path
â—Ź Query, Updateâ—Ź Internet MANET Encapsulation (IMEP)
– Reliable in order delivery– Link status: BEACON, HELLO
Dynamic Source Routing
â—Ź Source routingâ—Ź Each packet: complete route
â—Ź Route Discoveryâ—Ź Route Maintenanceâ—Ź Caching optimizations
Ad Hoc On-Demand Distance Vector
● Like DSR– on demand route discovery, maintenance
● Like DSDV– hop by hop routing, route sequence numbers
â—Ź Route Requestâ—Ź Route Reply
– Number of hops to destination● Maintenance
– Periodic HELLO
Simulation
â—Ź Methodology
â—Ź Results
â—Ź Other observations
â—Ź Related work
Methodology
â—Ź Goal: "Measure the ability of the routing protocols to react to network topology changes while continuing to successfully deliver data packets to their destinations"
â—Ź Scenarios
â—Ź Movement: Random Waypoint Model
● Communication: constant bit rate– no TCP
● Metrics– Packet Delivery Ratio– Routing Overhead– Path Optimality
Results: Packet Delivery
● Best to worst:– DSR, AODV, TORA,
DSDV
â—Ź DSR, AODV: load independent
â—Ź DSDV: stale routing
â—Ź TORA: routing loops from link reversal
Packet Delivery Details
Results: Routing Overhead
● Least to most overhead:– DSR, DSDV, AODV,
TORA
â—Ź DSR: decreasing incremental overhead
â—Ź AODV: less caching
â—Ź DSDV: constant overhead
â—Ź TORA: positive feedback loop -> congestive collapse
Routing Overhead details
Other Observations
â—Ź Overhead: DSR worse than AODV when measured in bytes
● DSDV updates: upon new sequence or metric number– Sequence: more overhead, better packet
delivery
â—Ź Broadcast reliability
● ARP/on demand protocol interaction:– Does not cache enough waiting packets
Related Work
● Park & Corson– TORA– Over simplified simulation: no node mobility
● Johnson & Maltz– DSR– Lacked radio propagation, MAC
● Freisleben & Jenson– DSDV, DSR– Simulation deficiencies (synchronization)
Paper Evaluation
â—Ź Strengths
â—Ź Weaknesses
â—Ź Further discussion points
Evaluation: Strengths
● Realistic Model– 802.11 MAC– Physical layer
● Detailed Comparison– 210 scenarios– Varied pause time, # of data sources
● Effective metrics– Packet delivery ratio– Overhead
● Detailed considerations– Considered implementation specific optimizations– Proposed protocol specific reasons for performance differences
Evaluation: Weaknesses
● Comparing very specific aspect of protocol– Only changes to network topology– No load/stress, normal case overhead
● Not real enough– Flat space, no obstructions– Too much movement– No device locality– Constant bit rate– Scalability– Effect of TCP
Evaluation: Overall
â—Ź Achieved what they said they would
â—Ź Other information needed for a more complete comparison
Discussion
● Implementation– Which protocol is easier/better?
● Node behavior– Malicious/lazy nodes?
â—Ź Power consumption
â—Ź Scalability
â—Ź Security