Use the following best practices for SIP trunk optimization:
A mix of clustered and non-clustered signaling group should not be administered for the same set of Session Manager and having the same port.
If an implementation must have multiple signaling group with the same Session Manager that are mix of clustered and non-clustered, then the port must be different.
All Session Managers that are administered in the cluster Session Manager form must have entity links administered between them in a star topology.
All Session Managers that are administered in the cluster Session Manager form must have Session Manager Release 8.0 or higher for SIP trunk optimization feature to work correctly.
Session Manager auto suggest feature that is administered on the route pattern form is deprecated with clustered signaling groups.
Primary Session Manager and secondary Session Manager associated with a station must be administered on the cluster.