The first group of simulation is to investigate the mobility feature of the protocol. Where,
the second group of simulation is to investigate the scalability of the protocol.
5.7.2.1 Packet header size
This metric can be considered as a good indication of the scalability feature for any
protocol. A protocol according to this metric is considered as scalable protocol if the
growth of group size is not followed by growth of header size. Figure 5.7 shows that
SARM provides superior scalability compared to the other two protocols. The results
obtained for extra header size added to the data packet in order to be delivered to the
group nodes. The results show that there is an increase in the header size for all the
protocols included in the evaluation. However, the increase in SARM is small in
comparison to DDM and E2M; this is because the extra header size in SARM contains
only the address of the next BNR and no need to carry any extra address in the header. In
E2M and DDM, the extra header size will include the addresses of the destinations for
DDM and part of the destination and XFs for E2M. Also it can be noticed that E2M
performs better than DDM, this is because E2M encodes part of the destinations
addresses and XFs nodes, which relatively the number of theses nodes will be less than
the number of the whole destination nodes.
Packet Header Size
SARM
—DDM
—2M E2M
Group size (nodes)
Figure 5.7 Packet header size for each data packet sent
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