2. Interdomain multicast routing

Inter-domain multicast routing presents a number of additional difficulties and challenges compared with intra-domain multicast routing. The aim is no longer to deploy IP multicast services within a service provider's network, but rather to enable broadcast services to be shared and distributed between multiple domains and service providers.

To achieve this, the candidate inter-domain multicast routing protocol must meet a number of requirements, including :

• the candidate protocol must allow and handle differences in topology and/or routing policy for unicast and multicast services;

• the candidate protocol must enable network operators to preserve their autonomy of control over their own RP: a service provider doesn't want to be dependent on third-party networks under any circumstances....