Chapter 7 Configuring Redundant ACE Appliances
Overview of Redundancy
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Cisco 4700 Series Application Control Engine Appliance Administration Guide
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Note
Redundancy is not supported between an ACE appliance and an ACE module
operating as peers. Redundancy must be of the same ACE device type and
software release.
Redundancy provides seamless switchover of flows in case an ACE becomes
unresponsive or a critical host or interface fails. Redundancy supports the
following network applications that require fault tolerance:
•
Mission-critical enterprise applications
•
Banking and financial services
•
E-commerce
•
Long-lived flows such as FTP and HTTP file transfers
This section contains the following topics:
•
Redundancy Protocol
•
Stateful Failover
•
FT VLAN
•
Configuration Synchronization
•
Configuration Requirements and Restrictions
Redundancy Protocol
You can configure a maximum of two ACE appliances (peers) for redundancy.
Each peer appliance can contain one or more fault-tolerant (FT) groups. Each FT
group consists of two members: one active context and one standby context. For
more information about contexts, see the
Cisco 4700 Series Application Control
Engine Appliance Virtualization Configuration Guide
. An FT group has a unique
group ID that you assign.
One virtual MAC address (VMAC) is associated with each FT group. The format
of the VMAC is: 00-0b-fc-fe-1b
-
groupID
. Because a VMAC does not change
upon switchover, the client and server ARP tables does not require updating. The
ACE selects a VMAC from a pool of virtual MACs available to it. For more
information about VMACs, see the
Cisco 4700 Series Application Control Engine
Appliance Routing and Bridging Configuration Guide
.