Cisco ASA Series Cli Configuration Manual page 330

Configuration Examples for ASA Clustering
Router or
Access Switch
Switch 1
Virtual Switch Link
ASA1
ASA2
ASA3
ASA4
1. Up to 4 units
The principle is to first maximize the number of active ports in the channel, and secondly keep the
number of active primary ports and the number of active secondary ports in balance. Note that when a
5th unit joins the cluster, traffic is not balanced evenly between all units.
Cisco ASA Series CLI Configuration Guide
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Router or
Access Switch
Switch 2 Switch 1
Virtual Switch Link
ASA1
ASA2
ASA3
ASA4
ASA5
2. 5th unit joined
Chapter 1 Configuring a Cluster of ASAs
Router or
Access Switch
Switch 2 Switch 1
Virtual Switch Link
ASA1
ASA8
3. Maximum of 8 units
Switch 2