TMS zl Management and Configuration Guide ST.1.1.100226

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Overview
HA Clusters
Figure 1-21. Active-Standby Mode
HA Cluster Operation Rules
The TMS zl Modules in an HA cluster synchronize their connection state
information by sending messages over the HA VLAN, which must be dedicated
to HA traffic. The HA VLAN is configured on the modules’ internal port 2,
which must be dedicated to HA traffic.
The modules in an HA cluster can be installed in the same switch chassis or
in different switch chassis.
If the modules are installed in different switches, the two switches must have
a Layer 2 connection on the HA VLAN. ProCurve recommends that the
switches be directly connected with redundant links. This precaution mini-
mizes the risk that two functioning modules lose their connection with each
other, which can cause both to assume the master role, creating problems in
filtering and forwarding traffic. In addition, both host switches must support
all TMS VLANs. Otherwise, the participant cannot properly provide failover.