CUCM Routing while getting cause Code 44

[eliba0001]

Hi 

in our system we got 2 Voice gateway ( sip-trunk) connected to CUCM .

Only one  PRI/E1 is connected for each Voice gateway for PSTN   .

we configure route list with both Voice gateway  as well 

I have 2 questions:

In one of the PRI/E1, all Time slots In  are busy ( means 30 calls are running ) , 

Phone from CUCM establish a call to PSTN and Voice Gateway response with SIP cause Code 44 ( circuit unavailable )

What should be the behavior of the CUCM routing ? should the call jump to the second  Voice gateway ?

question 2 :

while the PRI/E1 is down , phone establish a call --> CUCM send Invite to VGW 

VGW response with sip cause 503 (service unavailable because  no dial-peer) 

what should the CUCM routing behavior ? should the call jump to the second  Voice gateway

Thanks

Eli 

[TONY SMITH]

If all channels are busy, CUCM should receive a 486 "Busy Here" or maybe 404 "Not Found" message from the gateway.  Whether or not it hunts on to the other gateway will depend on how you have your Route List and Route Groups configured. There are also some setting in Service Parameter (Cluster Wide Route Plan) that determine whether CUCM should or should not hunt on under certain conditions particularly if they get a Busy or Not Found.  To get the behaviour I think you're looking for you should set these to False.

[eliba0001]

Hi 

Thanks for your answer , 

But In my case I receive "SIP/2.0 503 Service Unavailable" message from trunk, that's why turning these setting to True will not help in my situation.

Thanks

Eli 

[Roger Kallberg]

@eliba0001 You might want to reread @TONY SMITH rresponse. He did not write that you should set these service parameters to true, he wrote that you should set them to false. He is right in this, the two that are set to true in the screenshot should be set to false to get the CM to hunt to the second option in the route group.

[Sadav Ansari · Accepted solution]

503 service unavailable generally issue related to dial-peer

collect the debug voice ccapi inout and check the what incoming and outgoing dial peer matching.

Configure the correct destination IP address on on those dial peer. 

Or you can check the sip trunk device pool and it’s cm group mainly current dial peer destination ip (pub or sub ip) is not part of that cm group.

Pls rate if its Helpful. If this answered your question pls click Accept as Solution.

Sadav Ansari 

[TONY SMITH]

I think it defaults to routing on after a 503, same as it would if there was no response at all.  However going by the first post when the question was ..

"while the PRI/E1 is down , phone establish a call --> CUCM send Invite to VGW 

VGW response with sip cause 503 (service unavailable because  no dial-peer) "

I am pretty sure if the E1 is down, and therefore the dial peer is also down, the gateway will return a 404 not found. I will not swear to that because I've not done an ISDN with SIP trunk to CUCM, but that is the behaviour with H.323.  And in that case the default settings of both CUBE and CUCM mean that it does not hunt on.

There are two alternative solutions, change the Service Parameter on CUCM, or add "no dial-peer outbound status-check pots" to the CUBE which will make it treat a Down POTS line as if it was fully Busy.