0 7 15 31
Source ( Current BNR IP address)
Class D group Address (S,G)
Destination ( new LMR IP address (or) next BNR IP address)
Previous BNR IP address
Figure 4.3 eBNM message format
The rBNM message format is similar to the eBNM but simpler. rBNM format shown in
Figure 4.4 is as follows
([src= the IP_new branching node address; group address = (S,G); dest = previous branching node]).
|
0 7 15 31 |
|
Source ( Current (new) BNR IP address) |
|
Class D group Address (S,G) |
|
Destination (previous BNR IP address) |
Figure 4.4 rBNM message format
It can be noticed that these two messages are of fixed size which is different from that in
SEM or any previously discussed protocols, a remarkable advantage to the proposed work.
In SReM, the procedure of sending BNM messages is performed by one of the BNRs to
search for new BNR. This procedure starts by a new receiver joining the multicast group. So
BNRs are responsible for building the multicast tree which happens gradually and locally.
The only case that the source will participate in building the multicast tree is when a new
receiver is joining the multicast tree through an IMR located between the source and its next
BNRs. This kind of building the multicast tree is another remarkable advantage for SReM
over other related protocols like SEM [9], where the multicast tree is built in advance and
needs to be rebuilt whenever new joining or leaving process happens.
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