Ft Vlan - Cisco ACE-4710-K9 Administration Manual

Overview of Redundancy
Note

FT VLAN

Cisco 4700 Series Application Control Engine Appliance Administration Guide
7-6
HTTP connection states (Optional)
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Sticky table
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In a user context, the ACE allows a switchover only of the FT group that belongs
to that context. In the Admin context, the ACE allows a switchover of all FT
groups in all configured contexts in the appliance.
To ensure that bridge learning occurs quickly upon a switchover in a Layer 2
configuration in the case where a VMAC moves to a new location, the new active
member sends a gratuitous ARP on every interface associated with the active
context. Also, when there are two VLANs on the same subnet and servers need to
send packets to clients directly, the servers must know the location of the gateway
on the client-side VLAN. The active member acts as the bridge for the two
VLANs. In order to initiate learning of the new location of the gateway, the new
active member sends an ARP request to the gateway on the client VLAN and
bridges the ARP response onto the server VLAN.
Redundancy uses a dedicated FT VLAN between redundant ACEs to transmit
flow-state information and the redundancy heartbeat. Do not use this dedicated
VLAN for normal network traffic. You must configure this same VLAN on both
peer appliances. You also must configure a different IP address within the same
subnet on each appliance for the FT VLAN.
The two redundant appliances constantly communicate over the FT VLAN to
determine the operating status of each appliance. The standby member uses the
heartbeat packet to monitor the health of the active member. The active member
uses the heartbeat packet to monitor the health of the standby member.
Communications over the switchover link include the following data:
Redundancy protocol packets
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State information replication data
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Configuration synchronization information
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Heartbeat packets
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Chapter 7 Configuring Redundant ACE Appliances
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