Networking Guide
Chapter 5, Configuring Internet Protocol (IP) routing

Internet Router Discovery (IRD) protocol

Internet Router Discovery (IRD) protocol

The IRD protocol is an extension of the ICMP that is not a true routing protocol. It uses ICMP broadcast or multicast messages to enable hosts attached to multicast or broadcast networks to discover the IP addresses of their neighboring routers. It is best used in a small network within an autonomous system. It provides a low overhead method for routers to advertise themselves as default routers. It also provides a low overhead method for nonrouters to solicit the local network for existence of routers and add to their list of default routers the addresses of any routers that respond.

The following distinguishing features are provided by the IRD protocol:

For more information on this protocol, see RFC 1256.