The main office has the CCM cluster. Version 5.1.3
The site office has just IP Phones registered to the CCM in the main office via WAN.
The WAN has QoS policies in place at both the ends.
When the WAN is fully utilized(above 90%), the IP Phones in the site office are facing issues.
When the IP phone in the site office rings, the user in the site office presses the answer button on the IP Phone. But the call is not connected immediately. It takes a full 6-7 seconds for the call to get connected. However, once connected the call quality is good.
On troubleshooting this, I observed that the SCCP messages from the Phone to CCM (port 2000) are covered under QoS as we have QoS policy for the ACL "permit tcp any any range 2000 2002". The trouble is that the SCCP messages from the CCM to the Phone are not covered under any QoS policy. Hence the SCCP packets from the CCM to the IP phones suffer long delays.
Can you please tell me how to identify the SCCP messages from the CCM to the IP Phone, so that I can put appropriate QoS policies for that traffic as well?
Is it possible that the traffic from the CCM is coing from port 2000? Can you flip the ACL around like "permit tcp any range 2000 2002 any"?
it's the same, all SCCP traffic to/from phone and CUCM is port 2000, DSCP 24, PHB CS3 (default values)
maybe check you have it applied both ways with the same preference
if this helps, please rate