212777-A, February 2002 247CHAPTER 11High AvailabilityAlteon 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: “VRRP Overview” on page 248. This section discusses VRRP operation and Web OSredundancy configurations. “Failover Methods” on page 253. This section describes the three modes of high availabil-ity. “Web OS Extensions to VRRP” on page 259. This section describes VRRP enhancementsimplemented in Web OS. “High Availability Configurations” on page 263. This section discusses a few of the moreuseful and easily deployed redundant configurations.o “Active-Standby Virtual Server Router Configuration” on page 263o “Active-Active VIR and VSR Configuration” on page 265o “Active/Active Server Load Balancing Configuration” on page 267o “VRRP-Based Hot-Standby Configuration” on page 275 “Virtual Router Deployment Considerations” on page 277. This section describes issues toconsider when deploying virtual routers. “Stateful Failover of Layer 4 and Layer 7 Persistent Sessions” on page 283. This sectiondescribes how to enable stateful failover by mirroring Layer 7 and Layer 4 persistenttransactional states on the peer switch.
