Router Discovery Overview; Configuring Router Discovery - Nokia IPSO 4.0 Reference Manual

Note
Only the
IPSO implements only the ICMP router discovery server portion, which means that a Nokia
router can advertise itself as a candidate default router, but it will not adopt a default router using
the router discovery protocol.
The ICMP Router Discovery Service provides a mechanism for hosts attached to a multicast or
broadcast network to discover the IP addresses of their neighboring routers. This section
describes how you can configure a router to advertise its addresses by using ICMP Router
Discovery.

Router Discovery Overview

The router discovery server runs on routers and announces their existence to hosts. It does this
by periodically multicasting or broadcasting a router advertisement to each interface on which it
is enabled. These advertisements contain a list of all the router addresses on a given interface
and their preference for use as a default router.
Initially, these router advertisements occur every few seconds, then fall back to every few
minutes. In addition, a host can send a router solicitation, to which the router responds with a
unicast router advertisement, unless a multicast or broadcast advertisement is due in a moment.
Each router advertisement contains an advertisement lifetime field indicating for how long the
advertised addresses are valid. This lifetime is configured such that another router advertisement
is sent before the lifetime expires. A lifetime of zero (0) indicates that one or more addresses are
no longer valid.
On systems that support IP multicasting, the router advertisements are sent by default to the all-
hosts multicast address 224.0.0.1. However, you can specify the use of broadcast. When router
advertisements are being sent to the all-hosts multicast address, or an interface is configured for
the limited-broadcast address 255.255.255.255, all IP addresses configured on the physical
interface are included in the router advertisement. When the router advertisements are being sent
to a net or subnet broadcast, only the address associated with that net or subnet is included.
Note
Router discovery is not supported when clustering is enabled.

Configuring Router Discovery

Table 29
Nokia Network Voyager for IPSO 4.0 Reference Guide
server
portion of the Router Discovery Protocol is supported.
describes the parameters that you can configure for router discovery.
473