IGMP Deployment

GÉANT2 supports Any Source Multicasting (ASM), the traditional IPv4 multicast model. IPv4 multicast sources send IPv4 datagrams to the network, with the destination address of each IPv4 datagram set to a specific "group" address in the Class D address space (224/4). IPv4 multicast receivers register their interest in packets addressed to a group address, and the internetwork delivers packets from all sources in the internetwork to the interested receivers.

IPv4 multicast receivers register their interest in packets sent to group addresses through the Internet Group Management Protocol Version 2 (IGMPv2). IGMPv2 does not have any facility for receivers to specify which sources the receiver wants to receive from. IGMPv2 only allows (*,G) registrations (* = no source specified).

Source Specific Multicast (SSM) is another IPv4 multicast model. IPv4 multicast receivers register their interest in packets sent by specific sources to group addresses through IGMPv3. IGMPv3 supports (S,G) registrations (registrations based on multicast source or group).

Sources that send packets to group addresses in the 232/8 range (the SSM-specific range) may only be received by IGMPv3/SSM speaking receivers and networks.

Note: The Internet Group Management Protocol Version 3 (IGMPv3) can also be used in Any Source Multicast mode.

GÉANT2-Specific IGMP Guidelines

IGMPv3 is enabled on all routers and all Ethernet interfaces. This is to enable all Workstations in each PoP to send and receive multicast traffic inside and outside of GÉANT2.

Examples

Juniper Example

protocols { 
    igmp { 
        interface all { 
            version 2; # Version 2 
        } 
    } 
}