Redundancy

This section introduces AppDirector redundancy capabilities and includes the following topics:

Network Configurations

Configuration Guidelines

Global Redundancy Configuration

Failover Decision

Stateful Failover (Mirroring)

Physical IP Addresses versus Virtual IP Addresses Redundancy

Virtual Router Redundancy Protocol

Configuration Synchronization

Radware recommends installing AppDirector platforms in pairs to provide fault tolerance in the case of a single platform failure. Each pair of AppDirectors can function in an active/backup setup or active/active setup.

To achieve redundancy between pairs of AppDirector platforms, AppDirector supports the following methods are supported:

VRRP — Working with Virtual Router Redundancy Protocol enables dynamic redundancy to be maintained using a logical entity called a virtual router. (VRRP was initially developed to provide high availability for routers, hence the name virtual router. However, this protocol can be supported by a wide range of platforms that are not routers as it is not a routing protocol - it does not advertise IP routes or affect the routing table in any way). With VRRP, IP addresses are associated with the Virtual MAC addresses that are owned by the main platform, and are taken over by the backup platform at fail-over time.

Proprietary ARP — Working with Address Resolution Protocol enables monitoring of the other platform in a pair and checking its availability. Using Proprietary ARP redundancy, at the failover time, the IP addresses of the main platform are managed by the backup platform and are associated with the backup platform’s MAC address.

Radware recommends using VRRP as described above for AppDirector redundancy.