CUCM (Best Effort no MTP) and SIP GW DTMF and Media

[fedor.solovev]

Hello, Dear support team.

I have jabber -> CUCM 11.5 -> SIP Trunk -> 2911 GW15.3 -> PSTN E1.

CUCM SIP Trunk is by default without early offer.
First, I was thinking that cisco-rtp helped me.

voice class codec 4050
codec preference 1 g711alaw
codec preference 2 g711ulaw
dial-peer voice 4050 voip
description -= Incoming from CUCM =-
session protocol sipv2
incoming called-number 98T
voice-class codec 4050
dtmf-relay cisco-rtp rtp-nte
fax rate 14400
fax protocol t38 version 0 ls-redundancy 2 hs-redundancy 0 fallback pass-through g711alaw
no vad

However, eventually, it was not work again,

until I changed MTP at CUCM SIP Trunk Profile (best effort no MTP).

I was managed to configure DTMF and audio without HW MTP, though;

I didn’t got why BOTH

DTMF and audio itself didn't work without MTP configured as best effort (no MTP), while

 #show sip-ua calls shows the same information about the call at GW with and without Best Effort?

[Chris Deren]

You did not tell us what is the issue.

[fedor.solovev]

Hello, Chris.
Yes, you are right. It is rather a question then a problem, why under conditions mentioned above, DTMF and RTP itself didn't work without best effort at CUCM Trunk (both directions)?

[fedor.solovev · Accepted solution]

Guys,

since Inbound and Outbound dial-peers at GW were configured with rtp-nte, I am sure it was an IOS issue.
After GW reboot this problem disappeared.
I believe an IOS upgrade will help to eliminate this problem in the future as well.
Current version is c2900-universalk9-mz.SPA.154-3.M.bin