Figure 5.9 shows the packet delivery ratio when the multicast group size changes. This
evaluation gives another indication on the scalability degree of a protocol. SARM shows
more scalability over E2M and DDM. The reason for this improvement in scalability is
the use of BNRs in SARM.
Packet Delivery Ratio as a function of Group Size
—SARM
-Dd DDM
→-E2M
Group Size (nodes)
Figure 5.9 Packet delivery ratio
In E2M, when the number of group members increases, it will cause a huge traffic on
XFs which will cause loss of packets because of this traffic. At DDM, increasing the
number of group members means that this protocol will take time to add the new
members to the multicast list kept in the source. During the addition of new members
these members will not receive data packet which in conclusion the number of received
packets will decrease.
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