Nortel Networks WEB OS 212777 - Manual (Page 247)

212777-A, February 2002
247
C
HAPTER
11
High Availability
Alteon Web switches support high-availability network topologies through an enhanced imple-
mentation of the Virtual Router Redundancy Protocol (VRRP).
The following topics are discussed in this chapter:
n
“VRRP Overview” on page 248 . This section discusses VRRP operation and Web OS
redundancy configurations.
n
“Failover Methods” on page 253 . This section describes the three modes of high availabil-
ity.
n
“Web OS Extensions to VRRP” on page 259 . This section describes VRRP enhancements
implemented in Web OS.
n
“High Availability Configurations” on page 263 . This section discusses a few of the more
useful and easily deployed redundant configurations.
o “Active-Standby Virtual Server Router Configuration” on page 263
o “Active-Active VIR and VSR Configuration” on page 265
o “Active/Active Server Load Balancing Configuration” on page 267
o “VRRP-Based Hot-Standby Configuration” on page 275
n
“Virtual Router Deployment Considerations” on page 277 . This section describes issues to
consider when deploying virtual routers.
n
“Stateful Failover of Layer 4 and Layer 7 Persistent Sessions” on page 283 . This section
describes how to enable stateful failover by mirroring Layer 7 and Layer 4 persistent
transactional states on the peer switch.