Routing algorithms are the key elements in determining the network performance. Therefore,
in this thesis a model of logical topologies in the software has been proposed to examine the
performance of the logical topologies and their routing algorithms for large scale packet networks. A
number of topologies are investigated using the model 2 x 2 node. Different routing protocols are
used for forwarding packets in network. Routers keep up with a routing table for successful delivery
of the packets from the source node to the destined node. Most of the popular routing algorithms
used are RIP, OSPF, IGRP and EIGRP. In this paper we proposed an intelligent routing algorithm by
using AntNet algorithm for best effort IP networks, and tested this proposal algorithm to check its
performance.
8. Fig .4: system load against average no. of hops for logical network with deflection mode (no-buffer)
As can be seen from the figure, the number of hops increases very little with the system load
for small size networks (24N and 64N), whereas for large size network, the increase is linear for the
logical networks. This shows that for a large size networks, they are scalable and can cope with
increasing traffic when there is no buffer. When a buffer is employed in the nodes, the performance
of the networks and their routing algorithms increase dramatically, see fig. (5).
10. Fig .5: System load against no. of hops for logical networks with store-and-forward mode
(with buffer)
Table (1.1) shows the Comparing deflection routing (without-buffer) tests with the store-and-forward
(with-buffer) routing tests that there is an improvement in performance in the latter case.
However, this improvement is gained at the cost of system complexity.
Table.1: Comparison the average no. of hops for two types with different networks sizes.
Average number of hops
Network size 24(Nodes) 64(Nodes) 160(Nodes) 384(Nodes) 896(Nodes)
With buffer 3.15 4.73 6.22 7.84 9.59
Without buffer 3.66 6.00 8.77 12.31 16.70
B. Contentions
Fig. (6) shows the contention ratio versus the system load for deflection routing (without
buffer) for different network size. Contention ration increases slightly and gradually because these
networks can act as a 'buffer' when there is a need for buffering, where system loads increase
relatively to the size of the network.
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Fig .6: system load against contention ratio for logical network with deflection mode (no-buffer)