Internet videoconferencing and TV belong to the category of group communication unlike
others that are consisting of point-to-point communication or file transfers. These new
application often have a source and large number of receivers. An efficient multicast service
is required [22], since the use of multiple unicast routes is unfeasible in terms of bandwidth,
and server processing, since the media, which are mainly audio and video, demand a variety
of resources from the communications system.
In traditional group communication, data travels over a data link once, and is replicated by
intermediate routers in order to serve those clients who wish to receive the content. This
approach is not scalable as it frequently floods the network with data in the case of new
receivers.
To coup with the increase in the users, scalable multicast protocols is needed to perform the
data transfer to the users, these protocols should dynamically add the new users without a
huge traffic or reconstruction of the tree. For example, in videoconferencing application, if a
new person wants to share this application, the protocol should be able to start forwarding
data to this new user without interrupting the other users and at the same time if any of the
users wants to leave this application, the protocol must support a smooth leave to this user
and reconfigure the group locally and dynamically.
Applications like videoconferencing, TV and software update is considered as a group
communication applications and can benefit from the idea of scalable multicast routing
protocols concepts to deliver data from source to the set of receivers and to satisfy the
increase in the number of users for these applications. These protocols will dynamically add
and remove the receivers without any reconstruction of the multicast tree.
1.2 Multicast routing in MANETs
Routing protocol can be defined as a set of rules that specify how nodes communicate with
each other for information exchange. In general, a multi-hop routing protocol is needed in a
mobile ad hoc network, because two hosts wishing to exchange packets may not be able to