Chapter 19 - High Availability; Virtual Router Redundancy Protocol; Vrrp Overview - Radware Alteon Application Manual

Chapter 19 – High Availability
Alteon supports high availability network topologies through an enhanced implementation of the
Virtual Router Redundancy Protocol (VRRP).
This chapter describes the following topics:
• Virtual Router Redundancy Protocol, page 507
• IPv6 VRRP Support, page 518
• Failover Methods and Configurations, page 521
• IPv6 VRRP Configuration Examples, page 547
• Virtual Router Deployment Considerations, page 567
• Stateful Failover of Persistent Sessions, page 571
• Service-Based Session Failover, page 574
• Peer Synchronization, page 580

Virtual Router Redundancy Protocol

This section describes the following Virtual Router Redundancy Protocol (VRRP)-related topics:
• VRRP Overview, page 507
• Standard VRRP Components, page 508
• VRRP Priority, page 509
• Alteon Extensions to VRRP, page 510

VRRP Overview

VRRP eliminates single points of failure within a network. The protocol supports redundant router
configurations within a LAN, providing alternate router paths for a host.
In a high availability network topology, no device should be a single point of failure for the network
or cause a single point of failure in any other part of the network. This means that a network
remains in service despite the failure of any single device. To achieve this usually requires
redundancy for all vital network components.
Each participating VRRP-capable routing device is configured with the same virtual router IP address
and ID number. One of the virtual routers is elected as the master, based on a number of priority
criteria, and assumes control of the shared virtual router IP address. If the master fails, one of the
backup virtual routers takes control of the virtual router IP address and actively processes traffic
addressed to it.
Because the router associated with a given alternate path supported by VRRP uses the same IP
address and MAC address as the routers for other paths, the host's gateway information does not
change, no matter which path is used. A VRRP-based redundancy schema reduces administrative
overhead because hosts do not need to be configured with multiple default gateways.
Note: The IP address of a VRRP virtual interface router (VIR) and virtual server router (VSR) must
be in the same IP subnet as the interface to which it is assigned.
Document ID: RDWR-ALOS-V2900_AG1302
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