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MTP/Transcoders for Intercluster trunk Query

Hi,

I have 2 CCM clusters and an intercluster trunk configured between them.

There is this "Use MTP Required" in the trunk configuration. I understand that using this would allow me to use supplementary services for the older H323 gateways. I was told that this checkbox shouldn't be ticked because most of the gateways now are H.323v2.

Is this correct?

So now my this checkbox is not ticked. And I'm getting dropped calls when pple uses the supplementary services. :(

Secondly, should I configure hardware MTP/Transcoders for the Trunk's Media Resources/MRGL or should I use the software MTP?

In the CCM system guide, it mentions it but didn't specify should it be a hardware or software MTP:

------------------------------------

Make sure that each Cisco CallManager has its own MTP transcoding resource configured.

If transcoding is required between Cisco CallManager clusters, make sure that the intercluster trunk is configured with an MTP resource. All calls between Cisco CallManager clusters will go through the MTPs.

If all n MTP transcoding sessions are utilized, and an n + 1 connection is attempted, the next call will complete without using the MTP transcoding resource. If this call attempted to use the software MTP function to provide supplementary services, the call would connect, but any attempt to use supplementary services would fail and could result in call disconnection. If the call attempted to use the transcoding features, the call would connect directly, but no audio would be received. If a transcoder is required but not available, the call would not connect.

------------------------------------

Thanks for your time.

:)

Eugene

1 ACCEPTED SOLUTION

Accepted Solutions
Green

Re: MTP/Transcoders for Intercluster trunk Query

Please try to change in config mode.

timeoute h323 value...

increase it

8 REPLIES
Green

Re: MTP/Transcoders for Intercluster trunk Query

There is this "Use MTP Required" in the trunk configuration. I understand that using this would allow me to use supplementary services for the older H323 gateways. I was told that this checkbox shouldn't be ticked because most of the gateways now are H.323v2.

Is this correct?

Yes, normally for pretty old H323 gateways that support only V1 or integrations with H323 which dont support H245 TCS (Terminal Capability Set).

So now my this checkbox is not ticked. And

I'm getting dropped calls when pple uses the supplementary services. :(

Which are failing?

Transfers, Park, Hold?

Which codec is configured for ICT calls?

If using G729 change it to G711 and test.

Secondly, should I configure hardware MTP/Transcoders for the Trunk's Media Resources/MRGL or should I use the software MTP?

If using SW MTP using IPVMS service you should use G711.

Otherwise you can use HW MTP

New Member

Re: MTP/Transcoders for Intercluster trunk Query

Thanks for replying.

We have two CCMs, CCM_A and CCM_B.

In between these two CCMs, there is a intercluster trunk. We have configured both ends to use G711 and configured MRGL consisting of hardware transcoders and unicast MOH.

Currently, when Phone A (registered to CCM_A) calls Phone B (registered to CCM_B).

When the call is connected, I am able to put the call on hold. By pressing the hold,new call, conf, trnsfer softkey.

However after a short period, ranging from 5 minutes to 20 minutes, if either phone were to put the call using any method, the call would drop.

The phone still shows the call is connected, but there is no more RTP streaming. We are not able to press any of the softkeys except for the End call softkey.

Anyone able to help?

Thanks.

Eugene

Green

Re: MTP/Transcoders for Intercluster trunk Query

Any FW or Security device between CCM servers?

New Member

Re: MTP/Transcoders for Intercluster trunk Query

Oh yes we do have but only on one side.

But currently it is at open any any.

It's a ASA5520.

Thanks.

Green

Re: MTP/Transcoders for Intercluster trunk Query

Please try to change in config mode.

timeoute h323 value...

increase it

Green

Re: MTP/Transcoders for Intercluster trunk Query

to the max value

New Member

Re: MTP/Transcoders for Intercluster trunk Query

Thanks for your reply again.

Pretty lost about this issue.

I found these commands in the ASA:

timeout xlate 0:30:00

timeout conn 0:20:00 half-closed 0:15:00 udp 0:02:00 icmp 0:00:02

timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00

timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00

timeout uauth 0:05:00 absolute

Do i maximise the timeout for H323 only?

How about MGCP?

Thanks,

Eugene

New Member

Re: MTP/Transcoders for Intercluster trunk Query

You have solved our problem! :)

We realised that the call will drop exactly after 5 minutes.

This meaning after the call is connected for 5 minutes, we press the hold softkey and the call would drop.

After which, we tried checking the value of the 'timeout h323 00:06:00'. We tested again and now the call would drop exactly after 6 minutes.

Can I ask how does the call flow when this happen?

Phone A - FW - Intercluster Trunk at CCM A ---- Intercluster Trunk at CCM B - FW - Phone B.

Phone A calls Phone B, when call is connected, RTP stream is directly from Phone A to Phone B. If the call is not put on hold, the call would not drop. After which, the user press the hold softkey. How would the signalling be after this to cause the call drop?

Secondly, there are some other timeouts such as MGCP and H225. Should we increase the value for these as well? Is there any impact if we put too big a timeout value? Would this impact the utilization of the ASA firewall?

Thanks for your help!

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