Design and investigation of scalable multicast recursive protocols for wired and wireless ad hoc networks

route, when a route failure happenes. This solution will be discussed in details later in
this chapter.

In similar fashion to SReM and MoSReM, SARM builds tree connecting group members,
these members called a multicast session. This multicast session consists of:

- Multicast source node (S).

- A set of nodes called receivers.

- An multicast enabled intermediate nodes called Intermediate Multicast Routers
(IMRs)

5.5.1 Mobility messages in SARM

Performing mobility management in nodes and the ability to re-establish a new route,
when a link failure happens, is the key issue of the proposed protocol SARM.

As mentioned, the proposed SARM protocol is designed to take into consideration the
mobility in ad hoc networks. As soon as a link failure is detected by the periodical
messages (discussed later) or by the network layer, a local search will start to find a new
route instead of the broken one. The mobility feature will be discussed in detail in Section
5.6. To perform the mobility a new type of messages is introduced. These messages are
used to detect and repair a link breakage in the network. These massages are as follows:-

• BNR_UP:- this message is sent by a BNR to its upstream (previous) BNR stored
in previous BNR field in its MFT table. This message is sent periodically to
refresh the connectivity of BNR toward previous BNR. Figure 5.4 shows this
message format.

0                 7                     15                                 31

Source ( Current BNR IP address)

Destination (previous BNR IP address)

Figure 5.4 BNR_UP message format

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