DTMF Mismatch SIP to MGCP Fax

[VON CLAWSON]

Having a DTMF mismatch issue.  The SIP error received is 503 service unavailable cause=47.  Codec Mismatch.  When looking at the traces I get the following.

If I don't have a transcoder I get

isMTPNeededForMismatchOrConfig, MTPNeededDueToDTMFCapMismatch(2833/OOB) mtpinsertionReason=1 dtmfMTPSide=1

sendMTPXcoderAllocationRequest, allocate MTP

MRM::getMtpDeviceGivenMrgl DeviceName=MTP_10 DeviceType=110

sendMtpAllocateRequestToDevice MtpResource=MTP_10

getResourcesAllocated -- DeviceName=MTP_10 Ci=31719716 ResourceCount=1
getResourcesAllocated -- Logging RegionA=US164-LEG-SME-RGN Caps and MTP/XCoder Region=Default Caps
logCapabilitiesinTrace -- MTP/XCoder Device Caps = 4 2 25 257 259 258
logCapabilitiesinTrace -- Device Caps = 4 2
matchCapabilities-- savedOption=0, PREF_LIST, regionA=Default regionB=US164-LEG-SME-RGN latentCaps(A=0, B=0) kbps=8, capACount=6, capBCount=2
getResourcesAllocated -- Logging RegionB=VERIZON-SIP-TRUNK-FAX Caps and MTP/XCoder Region=Default Caps
logCapabilitiesinTrace -- MTP/XCoder Device Caps = 4 2 25 257 259 258
logCapabilitiesinTrace -- Device Caps = 4 2 11 12 15 84 10 83 82 9 107
matchCapabilities-- savedOption=0, PREF_LIST, regionA=Default regionB=VERIZON-SIP-TRUNK-FAX latentCaps(A=0, B=0) kbps=64, capACount=6, capBCount=11
getResourcesAllocated -- No matching caps for either side A or side B, MTP not allocated
getResourcesAllocated -- match1=0 match2=2
getResourcesAllocated -- allocateErrBitset=0x21
SendMTPResourceErrToSender - ERROR AllocateMtpResourceReq failed

If I have an IOS transcoder in the MRG

I get this

getMtpDeviceGivenMrgl DeviceName=MHO-NMS-TRANS1

resource_rsvp_AllocateMtpResourceErr Device=MHO-NMS-TRANS1 deviceCapIntersec=9

adjustDeviceTblMTP - Codec Mismatch

disconnOnResourceAllocationFailure, ERROR disconnOnResourceAllocationFailure - fails to allocate MTP/XCoder,connCount=2

The MGCP router is a VG204 and has this command

mgcp dtmf-relay voip codec all mode out-of-band

I have tried changing this to

mgcp dtmf-relay voip codec all mode nse

to try to not have to allocate an MTP or transcoder but is has not resolved the issue.

Any help would be very much appreciated.

Thanks

[Anthony Holloway]

On your SIP config, which DTMF technologies are you listing? Sounds like it's just rtp-nte. If so, enter sip-kpml after it too. You really should have one of each: inband/out of band, to avoid these types of issues. CUBE can DTMF interwork between just about all, if not all, DTMF relay types. That's relay types, which exlcludes DTMF in the audio stream, in which case a DSP is needed.

[VON CLAWSON]

So the whole path is third party SIP device Fax Machine -> CUCM Leaf 1 -> CUCM SME -> CUCM Leaf 2 -> VG202 - Fax machine

So no CUBE router involved at the time. DTMF relay is set to No Preference for all SIP trunks. I have tried to set the MGCP dtmf-relay to nte-ca as well but the traces still show that there is a mismatch between 2833 and OOB.

[Anthony Holloway]

I see. Thanks for the clarification on the topology, and the commands you've tried. Do you have the fm-package listed in MGCP? Is your MGCP gateway pulling config from CUCM?

Can you share the Leaf 1 SIP messages to/from the fax server, and the Leaf 2 MGCP packets debug, for a sample call? Please note what state the configuration is in for the debug.

As a pondering thought, it sounds like perhaps the SIP fax device doesn't support any DTMF relay at all, and so, it might not be possible to configure the MGCP gateway to avoid an MTP/XCODE. You may have to just use the service parameter in CUCM at the leaf level to not fail call if MTP allocation fails, and do not provide any MTP/XOCDE to the end points.