Gugrajah_Yuvaan_ Ramesh_2003.pdf

Simulation ofa Load Balancing Routing Protocol Chapter 3
In terms of average end-to-end delay, when offered load is high, the DLAR protocols
again outperform AODV, with DLAR 4 producing the least average end-to end delay
for all mobility scenarios and highest load. However, the AODV protocol begins
outperforming the DLAR protocols when the load is decreased. This was attributed
to the reply delay implemented in the DLAR protocols that allow the destination
nodes to wait for multiple route requests before transmitting the route reply so that
the destination can determine which is the best route to use. This delay therefore
disadvantages DLAR when traffic is low.
The results obtained show that the DLAR protocols, in particular DLAR 4, reduce
congestion in the network and therefore provide higher average packet delivery ratio
and lower average end-to-end delay for high offered traffic as compared to AODV,
which uses the shortest path. The decision to implement a load balancing protocol as
opposed to a conventional routing protocol that uses the shortest path needs to be
weighed against the added computational complexity inherent in determining the
optimal path as topology changes. Determination of signal quality and load in the
buffers implies combining information from the physical layer, data link layer, and
network layer, all of which employs valuable processor time. A network designer
needs to determine whether the improvements in performance justify the
incorporation of load balancing techniques especially with regard to determining
whether or not the load offered to the network will become high enough for the
advantages of the load balancing protocols to become apparent.
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