Cisco ASA Series Cli Configuration Manual page 347

Chapter 1 Information About Failover
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Note
If failover occurs during an active Cisco IP SoftPhone session, the call remains active because the call
session state information is replicated to the standby unit. When the call is terminated, the IP SoftPhone
client loses connection with the Cisco CallManager. This occurs because there is no session information
for the CTIQBE hangup message on the standby unit. When the IP SoftPhone client does not receive a
response back from the Call Manager within a certain time period, it considers the CallManager
unreachable and unregisters itself.
For VPN failover, VPN end-users should not have to reauthenticate or reconnect the VPN session in the
event of a failover. However, applications operating over the VPN connection could lose packets during
the failover process and not recover from the packet loss.
Intra- and Inter-Chassis Module Placement for the
ASA Services Module
You can place the primary and secondary ASASMs within the same switch or in two separate switches.
The following sections describe each option:
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Intra-Chassis Failover
If you install the secondary ASASM in the same switch as the primary ASASM, you protect against
module-level failure. To protect against switch-level failure, as well as module-level failure, see the
"Inter-Chassis Failover" section on page
Even though both ASASMs are assigned the same VLANs, only the active module takes part in
networking. The standby module does not pass any traffic.
IPv6 clientless or Anyconnect sessions
Citrix authentication (Citrix users must reauthenticate after failover)
Intra-Chassis Failover, page 1-11
Inter-Chassis Failover, page 1-12
Intra- and Inter-Chassis Module Placement for the ASA Services Module
1-12.
Cisco ASA Series CLI Configuration Guide
1-11