CUCM 8.6.2.21900-5 and H323 Gateway Issues

[Ayodeji Okanlawon]

Guys,

I recently added a new h323 gateway to uor cluster and I observed some very weird issues. During call setup, CUCM never sent any h245 negotiation. All I see is h225 call setup and call progress report, I do not see any h245 TCS, OLC, Master slave determination and as such call fails. I know there is a bug  CSCtq96181 with cucm 8.6 but this is related to unable to add or edit h323 gateway.

Is this another bug

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"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson       

[Ayodeji Okanlawon]

Thanks Harmit...If its a TCP issue then why do I see the h225 setup message? H323 h225 runs on TCP port 1720. If this works then why would h245 signalling not work..Are you suggesting that there is a possibility that the ephemeral TCP port range for the h245 signalling is blocked while the h225 port is allowed? I worked extensively with the firewall team and they didnt see a single drop from the firewall during a test call..

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"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson

[Harmit Singh]

H.225 layer will establish a TCP connection between the two H323 devices and H.245 layer will establish a seperate TCP connection. Taking a packet capture from both devices would tell us more on this. I'm not concluding this is a firewall issue but I'm not ruling it out yet either :-) But like I said, it could even be an issue with:

1>     the UCM node's H323 stack or

2>     with the IOS H323 stack.

To rule both out, try:

1>     pointing the gateway to a different UCM node

2>     reload the gateway.

Regards,

Harmit.

[Suresh Subramanian]

The port we opened is TCP/UDP: 32768-65535 in our firewall. As the dynamic H245 ports are in between 11000 - 65535, i suspect the firewall is blocking the TCP connection for H245.

[Suresh Subramanian]

Harmit, attached are the debugs. pls have a look.

[Harmit Singh]

Thanks Suresh. I reviewed them. Nothing seems wrong from the H323 stack perspective. Packet Captures should help reveal why a TCP connection for H.245 signaling cannot be established. Packet captures would be need from both UCM and the gateway. I know this isnt the easiest thing to have set up but would add more value to the root cause. The other thing to do would be have the entire range 11000 - 65535 opened on the firewall temporarily and test if that take care of the issue.

Regards,

Harmit.

[sumiaror]

Hi Harmit,

I was experiencing the same issue with CUCM System version:8.6.2.22900-9 and was getting the following error in the traces: (SDI)ERROR: Fail to setup H245 signaling connection. After taking this to network team we figured out that they were suppose to exclude subnet for optimization but they only added it as a desitantion not as a source.

Link was very helpful.

Regards

Sumit Arora

[noc]

Thank you Sumiaror, your response of pointing out the optimization helped us resolve the issue..

Our issues was Intersite calls from US to UK not working via the ICT..and the traces show the below error..

ccm trace error:

10:17:37.074 |TranslateAndTransport(83)::waitForSdlRsp_TcpAwaitRespTimer - ERROR: Fail to setup H245 signaling connection!!!|6,100,28,83.1^*^*

sdl trace error:

002012469 |2016/12/15 10:17:37.074 |100 |AppError  |||TranslateAndTransport(6,100,21,83)|||H245Log: Process=TranslateAndTransport LogicalChannelNumber=1011 -- TCP ERROR: TcpAwaitRespTimer times out, or received SdlCloseInd from H245Handler, Perform cleanup of H245 Session

We had riverbed optimize the traffic between two sites and the voice subnet was not excluded. The strange thing is we have this setup working for long time and suddenly the issue occurred in one direction only ( US to UK)

The issues was resolved after excluding the voice subnet from optimization..