IP-to-IP Call Transfer problem

Answered Question
Dec 17th, 2008

Hi,

my diagram as below

Phone1---CCM1----GW1----(IP Network)----GW2---CCM2---Phone2 | |---Phone3

I configured all using G711u. The problem is that when Phone1 call Phone2, it works fine. But when Phone2 press Transfer to transfer to Phone3, the call drops.

I know CCM dont have H450 capability, but still dont have any solution to solve this problem yet.

Does anybody know how to fix?

Thanks million!

I attached config of two GWs

I have this problem too.
0 votes
Correct Answer by Nicholas Matthews about 7 years 11 months ago

This sounds like a combination of a DTMF relay problem and codec mismatch.

Make sure that the third phone has a transcoder available, and check the dial peers you're matching for calls with 'debug voip dialpeer' to make sure you're matching the right dial peer for each call leg.

Also, try 12.4(22)T. It's got tons of CUBE updates.

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Nicholas Matthews Wed, 12/17/2008 - 05:54

A couple of things to try:

voice service voip

h323

empty-capability

That allows for H323 call holds.

Next:

voice service voip

no supplementary h450.12

no supplementary h450.2

no supplementary h450.3

See if this works.

Next, make sure you have an MTP availble either in the default list or the MRGL associated with the H323 gateways on CUCM.

Then, enable both inbound and outbound fast start, and uncheck 'wait for far-end h245'. Reset the gateways.

If that doesn't work, upgrade your CUBE routers to 12.4(22)T.

If that doesn't work, you'll need to get CCM traces and debugs, and it may be hairier.

Best of luck.

-nick

huydien3384 Wed, 12/17/2008 - 21:41

I tried everything you listed above, but still not success. I notice some cases:

- When I enable in/outbound faststart on CCM1 & CCM2, Phone 1 call to Phone2, th phone ring but when I pickup, call drops.

- When I enable in/outbound faststart only on CCM1 or CCM2, call success and I can transfer the call, but only at the side I enable in/out faststart.

I'm using Router 2811 with IOS 12.4(15)T adventerprisek9_ivs.

Any idea?

huydien3384 Wed, 12/17/2008 - 22:31

An other thing is when enable in/outbound faststart, I can call to PSTN but cannot put more digit after that (for example, when call to CallCenter, cannot press "1 for Sales, 2 for Technical"...)

Correct Answer
Nicholas Matthews Thu, 12/18/2008 - 20:33

This sounds like a combination of a DTMF relay problem and codec mismatch.

Make sure that the third phone has a transcoder available, and check the dial peers you're matching for calls with 'debug voip dialpeer' to make sure you're matching the right dial peer for each call leg.

Also, try 12.4(22)T. It's got tons of CUBE updates.

huydien3384 Fri, 12/19/2008 - 02:19

After adding xCoder, now i can transfer the call. But I dont understand why it needs xCoder because I use only g711u, could you plz explain more detail?

If I want to use g729 between two GWs, how do I do that? DSP resources must be manage/control by call-agent (CCM or CME), doesnt it?

I tried to change Outbound Faststart codec to g729 and changed codec in dial-peer of Voice GW, but not successful

Thank you very much, Nic!

Nicholas Matthews Fri, 12/19/2008 - 05:54

It's hard to say without looking at all the regions and the SIP messaging.

Somewhere in the call flow you've got a g711/729 call, and the third phone is 729/711.

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