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19432
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10
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29
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Hold causes calls to disconnect

nick anderson
Level 1
Level 1

Hello,

I have a UCM 6.1 cluster with several h323 gateways. I am having a problem with the Hold/Transfer features on one gateway.  The gateway is a 2851 running 12.4(24)T with one NI2 PRI.  The gateway and phones are on the same local VLAN, and the CM server is across a router on a different network.

Station-Station calls work fine.  When a call is placed on hold, the MOH is delivered and the call can be retreived.

Calls coming in through the gateway are able to complete.  Unity is able to deliver prompts and record.  However, placing the call on hold causes it to be immediately dropped.  A Q931 debug on the gateway reports a "Temporary Failure", but otherwise I get no errors reported.

I'll be glad to post any other traces that would help...I was not sure what router debugs would be helpful, or which log files would be most relevant.

Any direction at all would be great.

29 Replies 29

Aaron Harrison
VIP Alumni
VIP Alumni

Hi

Try:

Debug cch323

A quick stab in the dark would suggest it might be a problem with MoH being played to the GW.

Regards

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

I have attached a debug for 1 test call. I included the q931 and cch323 all.  I see the following message near the disconnect: "Timer [CCH323_H245_UCHAN_TIMER] expired".

Jaime Valencia
Cisco Employee
Cisco Employee

Look in the app log for any MTP errors.

The usual cause for this is that the H323 lacks the MTP required, or if configured it cannot allocate the MTP

There was some documentation that explained this but i cannot find it right now.

HTH

java

If this helps, please rate

www.cisco.com/go/pdihelpdesk

HTH

java

if this helps, please rate

Is 'Application  Logs -> CiscoSysLog' the log file you meant?  If so, there are no MTP  messages in the log on either the Publisher or Subscriber.

I have tried using an MTP on the Gateway and on Call Manager in the Media Resource Group.  It did not affect the issue.

Can you post the router config?  Also, do you hear Hold music if the Vmail AA puts you on hold for a transfer?  That would come from the media defined for the VoiceMail ports but still back to the GW.  This would eliminate the GWs ability to pass on G711 hold music.  Also, can you set up a phone to not play the music?  If so, does the call still drop?

Hi Nick,

Firstly I would verify whether placing a call on hold which excludes any MoH resource exhibits the same symptoms as Aaron had mentioned.  In this scenario I would expect Tone-On-Hold, and for the call to be successfully resumed.  Incidentally are you running multicast or unicast on your MoH server?, also check that you have ccm-manager music-on-hold configured on your gateway.

Rgds

Allan.

All of my MOH sources are unicast.

As I posted above,  removing the Gateway's access to any MOH source allows the call to be  placed on hold and resumed. Based on wireshark (and my region settings) MOH is coming in as G.729.  I am not familiar with the commands for  ccm-manager music-on-hold.  Do you know where that is documented?

Router config is attached.

Is the trancoding resource registered ?  I see you have it defined but I generally add the following to the CCM Group:

sccp ccm   group 1      

associate ccm 1 priority 1      

associate ccm 2 priority 2      

associate ccm 3 priority 3      

associate profile 20 register MTP_SiteName_GW1      

associate profile 10 register CFB_SiteName_GW1 

those are my MTPs and Conf resources pre-defined in my UCM config.  They would contain the local router resources.

Also, under your DSPFARM PROFILE you could try adding "g729r8" and "g729br8" to cover all your G.729 bases

Finally,  to add MOH to the ccm-manager fallback section of the config for MoH in SRST mode

moh       

(please rate if this was useful or if I was way off base)

Aaron Harrison
VIP Alumni
VIP Alumni

Hi

So... looks to me like it's having trouble setting up the media (h245 being responsible for media neg etc).

I see G729 being used; if you are running a default MoH config then it only supports G711 (G729 sounds bad for music) so it will try to invoke a transcoder. Do you have any transcoders?

A quick test might be to go into Service Parameters for the IP Voice Media Streaming service, and enable the parameter that allows G729 streaming. If it then holds OK, you at least know where the problem lies (roughly).

Regards

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

I have a transcoder registered, and in that phone's Media Resource Group (config below).  I checked the Service Parameters for both CM servers, and all 4 codecs were already enabled.

It seems like it should have everything it needs =(

sccp local GigabitEthernet0/0
sccp ccm 10.192.36.10 identifier 2 priority 2 version 6.0
sccp ccm 10.192.36.11 identifier 1 priority 1 version 6.0
sccp
!
sccp ccm group 1
bind interface GigabitEthernet0/0
associate ccm 1 priority 1
associate ccm 2 priority 2
associate profile 1 register DFW-2851-tnc
!
dspfarm profile 1 transcode 
codec g711ulaw
codec g711alaw
codec g729ar8
codec g729abr8
maximum sessions 4
associate application SCCP

!

Hi

So... you have an MRGL on the phone hmmm?

The way this works is that the system will play out the MOH source assigned to the phone. The system will do this using the resources applied in the MRGL assigned to the gateway.

The phone could be the other side of the world, so there's no point using a transcoder or music source from there.

What devices do you have on this site that require a transcoder based locally? If all you have on this site are gateways and phones, you can almost guarantee you don't need one on this gateway (you need a transcoder only where a stream must be switched between codecs due to one end not supporting the codec in use on the WAN, and the transcoder should be collocated with the device that doesn't support the WAN codec - commonly this includes any flavor of Unity not enabled for G729, UCCX running G711, ARC, etc.).

I would do one of these two things:

1) Temporarily shut off MoH to prove that hold then works (by stopping the MoH part of the IP VMS service, not the whole thing)

2) Or ensure that all your MoH's are in MRGs, and remove any MoH MRGs from the gateway.

That it is failing to set up H245 suggests a media problem to me, and if there were no MoH there is just a local tone generated...

Regards

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

You were right on about the MOH...  I took the MOH source out of the Gateway's MRGL (I had only done that for the phone before...), so that the Gateway had no access to any MOH sources. I was then able to place a call on hold and resume it normally.

Now I dont understand why I can't get MOH to the gateway though...  The MOH source can play to the phones successfully.  When I do a Wireshark trace on the gateway I see 4 seconds of RTP for a G.729 stream after hold is pressed, but then the call is connected and the stream is stopped.  At least I know where to focus now.

The only devices on-site are the 1 gateway and several phones.  Based on my Region relationships in call manager, everything should be coming to me via G.729.  I defined the local transcoder as a troubleshooting test.  If I dont need it, I can remove it from the config.

Hi

OK - do you have MTP turned on in the gateway config in CCM?

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

I added a MOH souce back to the MRGL that both devices are in.

When I leave MTP unchecked on the gateway, I get 4 seconds of RTP, then the call drops (as before).

When I check MTP I get Beep Tones instead of music, but the call is retreivable (same behavior I had when there were no MOH sources in the MRGL).

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