 | Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |
Router discovery uses Internet Control Message Protocol (ICMP) router advertisements and router solicitation messages to allow a host to discover the addresses of operational routers on the subnet. Hosts must discover routers before they can send IP datagrams outside their subnet.
Router discovery allows a host to discover the addresses of operational routers on the subnet. The JUNOS software implementation of router discovery supports server mode only.
Each router periodically multicasts a router advertisement from each of its multicast interfaces, announcing the IP address of that interface. Hosts listen for advertisements to discover the addresses of their neighboring routers. When a host starts, it can send a multicast router solicitation to ask for immediate advertisements.
The router discovery messages do not constitute a routing protocol. They enable hosts to discover the existence of neighboring routers, but do not determine which router is best to reach a particular destination.
This chapter discusses the following topics that provide background information about ICMP router discovery:
| Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |