Section 4.11. Multicast Router Discovery (MRD)

4.11. Multicast Router Discovery (MRD)

Multicast Router discovery is a general mechanism that allows for the discovery of multicast routers. It does not depend on a specific multicast routing protocol. It is specified in RFC 4286 and introduces three new message types:

Multicast Router Advertisement (message type 151)

This message is sent by routers to advertise that IP multicast forwarding is enabled. It is sent from a link-local Source address to the All-Snoopers multicast address (FF02:0:0:0:0:0:0:6A).

Multicast Router Solicitation (message type 152)

This message is sent by devices in order to solicit Advertisement messages from multicast routers. It is sent from a link-local Source address to the all-routers multicast address (FF02:0:0:0:0:0:0:2).

Multicast Router Termination (message type 153)

This message is sent by routers to advertise that it stops IP multicast routing functions on an interface. It is sent from a link-local Source address to the All-Snoopers multicast address (FF02:0:0:0:0:0:0:6A).

All MRD messages are sent with an IPv6 Hop Limit of 1 and contain the Router Alert Option.

Now that you know how all the cool functionality of IPv6 works, the next chapter discusses what you need to know about security with IPv6.