Foundry Networks Switch and Router Installation And Configuration Manual page 863

This chapter describes how to configure the Foundry Standby Router Protocol (FSRP), a Foundry Networks
proprietary protocol that provides redundant paths between two routers.
Details for configuring FSRP with the CLI and the Web management interface are shown. For detailed summaries
of all CLI commands, including the syntax and ranges of parameter values, see the Foundry Switch and Router
Command Line Interface Reference.
For information about the differences between VRRP and the Foundry Standby Router Protocol (FSRP), see
"Differences Between FSRP and VRRP" on page 22-5.
Overview of Foundry Standby Router Protocol (FSRP)
FSRP allows alternate paths to be provided to a host. To provide path redundancy between given hosts, a virtual
router with its own unique IP addresses is created. The virtual router is created by assigning these unique IP
addresses to ports on existing routers in the network—routers that could provide a path between the given hosts.
NOTE: Virtual IP router addresses are in addition to the IP address assigned to each IP interface.
For example, in Figure 22.1, suppose you want to provide continual connectivity between Host 1 and Host 3 with
the use of redundant paths. A virtual router is created by assigning the same virtual router IP address to all
physical interfaces that will provide redundant paths for that portion of the network. Virtual router IP address
192.53.5.1 is assigned to interfaces A and B, and the virtual router IP address 192.55.4.1 is assigned to interfaces
C and D. Notice that in both cases, these virtual addresses are in addition to their physical IP addresses.
The virtual IP address also serves as the default router for the hosts. Hosts 1 and 2 reference the virtual IP router
address 192.53.5.1 as their default router and Host 3 references the virtual router IP address, 192.55.4.1.
If Router 1 goes down, then Router 2 provides connectivity between Host 1 and Host 3.
December 2000
Chapter 22
Configuring FSRP
22 - 1