Cisco Cisco MGX 8880 Media Gateway Release Notes

Changing the routing priority for DAX connections does not change the priority of the associated 
SVCs. The SPVCs are not derouted and rerouted if just the endpoint parameters are changed, and 
routing priority is an endpoint parameter. Also, because DAX connections are never derouted even 
if the user-network interface (UNI) port stops responding and the rrtcon command is not supported 
for DAX connections, the routing priority change is never reflected. The only way for the routing 
priority change to be reflected is to execute the dncon and upcon commands. Because DAX 
connections are never derouted, the effect of this limitation is voided.

Priority routing operates in a best effort manner for the following reasons:

Two in-order releases can still arrive out of order at the master node if they take two different 
paths.

Under congestion scenarios releases can be expected to be transmitted out-of-order. This is 
because releases of other calls must not be held up if you are not able to send releases on one 
of the interfaces because it is congested. The calls that were not released could be higher priority 
calls.

Lower priority SPVCs can be routed ahead of higher priority SPVCs. This can happen if you 
have repeatedly failed to route higher priority SPVCs. To prevent starvation of lower priority 
SPVCs, the software starts to route lower priority SPVCs. The software eventually addresses 
the higher priority SPVCs later.

These notes pertain to SPVC interoperability:

Network-to-Network Interface (NNI) SPVC Addendum Version 1.0 is not supported.

CC (Continuity Check) is not available at the slave end of a single-end SPVC.

Reporting AIS detection to Cisco Wide Area Network Manager (CWM) is not available at the slave 
end of a single-end SPVC.

The slave end of a single-end SPVC is not visible to CWM.

If single-end SPVCs originated from MGX switches, they can only be configured through CLI and 
not from CWM in the current release.

Single-end provisioning is not supported for DAX connections.

SPVC statistics are not available for the slave endpoint of a single-end SPVC because this endpoint 
is nonpersistent.

When the persistent slave endpoint of an existing SPVC connection is deleted and the master 
endpoint is allowed to remain, the connection might become established as a single-end SPVC 
connection. In this case, CWM shows the connection as Incomplete.

Override of SVC connections on a virtual path identifier (VPI) due to an incoming SPVP request for 
that VPI is not supported. The following override options are supported only: