Fax Configuration over the MGCP

Answered Question
May 29th, 2008

Hi,

I want to configure Voice gateway and Unified Call Manager 6.1 for the Fax Server (GFI Fax maker). Fax server support only SIP and T.38 for fax protocol.

The Voice gateway is already configured with unified Call Manager using MGCP protocol.

Can any body help me out regarding this scenario.

Regards,

Zeeshan

I have this problem too.
0 votes
Correct Answer by Michael Hanes about 8 years 6 months ago

I am not familiar with the GFI Fax maker fax server but if it supports T.38 over SIP then this should work, especially if this fax server uses a Dialogic fax engine such as SR140.

On the Unified CM, you need to configure a SIP trunk pointing to your fax server using the G.711 codec. On your existing MGCP gateway, you need to configure protocol-based T.38 fax relay. By default the Cisco MGCP gateways use an NSE-based switchover for T.38. The commands to configure protocol-based T.38 on the MGCP gateway are -

no mgcp fax t38 inhibit

mgcp default-package fxr-package

mgcp package-capability fxr-package

The first two commands above should be enabled by default. You must then reset the MGCP process on the gateway for these commands to work ("mgcp", "no mgcp" in config mode).

Confirm that you have the call routing configured correctly on Unified CM and then give this a try and let us know how it works. You also may want to contact the fax server vendor and confirm interoperability with Unified CM and see if they have sample configs available.

Regards,

David

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Correct Answer
Michael Hanes Thu, 05/29/2008 - 07:15

I am not familiar with the GFI Fax maker fax server but if it supports T.38 over SIP then this should work, especially if this fax server uses a Dialogic fax engine such as SR140.

On the Unified CM, you need to configure a SIP trunk pointing to your fax server using the G.711 codec. On your existing MGCP gateway, you need to configure protocol-based T.38 fax relay. By default the Cisco MGCP gateways use an NSE-based switchover for T.38. The commands to configure protocol-based T.38 on the MGCP gateway are -

no mgcp fax t38 inhibit

mgcp default-package fxr-package

mgcp package-capability fxr-package

The first two commands above should be enabled by default. You must then reset the MGCP process on the gateway for these commands to work ("mgcp", "no mgcp" in config mode).

Confirm that you have the call routing configured correctly on Unified CM and then give this a try and let us know how it works. You also may want to contact the fax server vendor and confirm interoperability with Unified CM and see if they have sample configs available.

Regards,

David

thisisshanky Thu, 05/29/2008 - 07:42

I d also suggest adding following commands.

no mgcp fax t38 ecm

mgcp fax rate 14400

no ccm-manager fax protocol cisco

####- disables cisco fax relay.

I have a CM 6.1 with a GFI fax server

using mgcp

it works with this mgcp config

mgcp

mgcp call-agent 10.18.9.12 2427 service-type mgcp version 0.1

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

mgcp rtp unreachable timeout 1000 action notify

mgcp modem passthrough voip mode nse

mgcp package-capability mf-package

mgcp package-capability rtp-package

mgcp package-capability res-package

mgcp package-capability sst-package

mgcp package-capability fxr-package

mgcp package-capability pre-package

no mgcp timer receive-rtcp

mgcp sdp simple

no mgcp fax t38 inhibit

mgcp rtp payload-type g726r16 static

but the site has regular power outages that last longer than their UPS...and when CM and voice gateway come back up the mgcp config changes and fax server no longer works

it changes to

no mgcp package-capability res-package

no mgcp package-capability fxr-package

any thought on how i could prevent this

thanks

Colum

Ayodeji oladipo... Wed, 08/27/2008 - 07:31

Do you have the command ccm-manager config-server command.

It looks as if the CCM attempts to reconfigure the MGCP gateway.

If you have that command, remove it.

Michael Hanes Wed, 08/27/2008 - 07:43

This is a bug with the ccm-manager config feature. The Cisco defect id is CSCsr41541. The fix for this defect has not yet been integrated into an IOS release that is downloadable from cisco.com but I am guessing that the next 12.4 or 12.4T release will have it. If you want more information on this defect and the availability of its fix, then your best bet would be to contact the Cisco TAC.

The other option/workaround is to disable the ccm-manager config feature once you have the desired configuration working on your voice gateway.

Regards,

David

zeeshan.nadeem Wed, 08/27/2008 - 23:23

I have this IOS (c2800nm-spservicesk9-mz.124-20.T.bin)and i rebooted (Reload) my voice gateway but the configuration didnt changed.

Regards,

Zeeshan

nikger1980 Thu, 12/13/2012 - 02:49

Hi there,

i have the same issue with CCM 7.1.2 and 3845 (12.4 ios) mgcp controlled gw's.

The call proceeds, but when one fax rings once, then the call fails..

I think that is something to the "handshaking" , but the debug shows me an "Requested circuit/channel not available" error.

I am sending you my "sh mgcp" results :

VGW-S173A-FL5-1#sh mgcp

MGCP Admin State ACTIVE, Oper State ACTIVE - Cause Code NONE

MGCP call-agent: CCM-S173A-FL5-2 2427 Initial protocol service is MGCP 0.1

MGCP validate call-agent source-ipaddr DISABLED

MGCP validate domain name DISABLED

MGCP block-newcalls DISABLED

MGCP send SGCP RSIP: forced/restart/graceful/disconnected DISABLED

MGCP quarantine mode discard/step

MGCP quarantine of persistent events is ENABLED

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

MGCP dtmf-relay for voAAL2 is SDP controlled

MGCP voip modem passthrough disabled

MGCP voaal2 modem passthrough disabled

MGCP voip modem relay: Disabled

MGCP T.38 Named Signalling Event (NSE) response timer: 200

MGCP Network (IP/AAL2) Continuity Test timer: 200

MGCP 'RTP stream loss' timer disabled

MGCP request timeout 500

MGCP maximum exponential request timeout 4000

MGCP gateway port: 2427, MGCP maximum waiting delay 3000

MGCP restart delay 0, MGCP vad DISABLED

MGCP rtrcac DISABLED

MGCP system resource check DISABLED

MGCP xpc-codec: DISABLED, MGCP persistent hookflash: DISABLED

MGCP persistent offhook: ENABLED, MGCP persistent onhook: DISABLED

MGCP piggyback msg ENABLED, MGCP endpoint offset DISABLED

MGCP simple-sdp ENABLED

MGCP undotted-notation DISABLED

MGCP codec type g711ulaw, MGCP packetization period 20

MGCP JB threshold lwm 30, MGCP JB threshold hwm 150

MGCP LAT threshold lwm 150, MGCP LAT threshold hwm 300

MGCP PL threshold lwm 1000, MGCP PL threshold hwm 10000

MGCP CL threshold lwm 1000, MGCP CL threshold hwm 10000

MGCP playout mode is adaptive 60, 40, 1000 in msec

MGCP Fax Playout Buffer is 300 in msec

MGCP media (RTP) dscp: ef, MGCP signaling dscp: af31

MGCP default package: mt-package

MGCP supported packages: gm-package dtmf-package trunk-package line-package

                         hs-package rtp-package atm-package ms-package dt-packag

e

                         mo-package res-package mt-package sst-package fxr-packa

ge

                         pre-package md-package

MGCP Digit Map matching order: shortest match

SGCP Digit Map matching order: always left-to-right

MGCP VoAAL2 ignore-lco-codec DISABLED

MGCP T.38 Max Fax Rate is DEFAULT

MGCP T.38 Fax is ENABLED

MGCP T.38 Fax ECM is ENABLED

MGCP T.38 Fax NSF Override is DISABLED

MGCP T.38 Fax Low Speed Redundancy: 0

MGCP T.38 Fax High Speed Redundancy: 0

MGCP Fax relay SG3-to-G3: ENABLED

MGCP Fax relay ANSam suppression: DISABLED

MGCP control bind :DISABLED

MGCP media bind :DISABLED

MGCP Upspeed payload type for G711ulaw: 0,  G711alaw: 126

MGCP Dynamic payload type for Cisco fax indication: 96, Cisco fax ack: 97

MGCP Static payload type for G.726-16K codec

MGCP Dynamic payload type for G.726-24K codec

MGCP Dynamic payload type for G.726-32K codec

MGCP Dynamic payload type for G.Clear codec

MGCP Dynamic payload type for NSE is 100

MGCP Dynamic payload type for NTE is 99

MGCP rsip-range is enabled for TGCP only.

MGCP Comedia role is NONE

MGCP Comedia check media source is DISABLED

MGCP Comedia SDP force is DISABLED

MGCP g729 variants use static payload type and contain annexb in SDP

MGCP Guaranteed scheduler time is DISABLED

MGCP Disconnect delay error recovery DISABLED

MGCP DNS stale threshold is 30 seconds

and my sh run , mgcp part :

mgcp

mgcp call-agent CCM-S173A-FL5-2 2427 service-type mgcp version 0.1

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

mgcp package-capability rtp-package

mgcp package-capability sst-package

mgcp package-capability pre-package

mgcp default-package mt-package

no mgcp timer receive-rtcp

mgcp sdp simple

mgcp fax t38 ecm

mgcp rtp payload-type cisco-pcm-switch-over-alaw 126

mgcp rtp payload-type g726r16 static

mgcp behavior g729-variants static-pt

!

mgcp profile default

!

!

!

dial-peer voice 10 pots

service mgcpapp

!

!

Anyone with any idea.. ?

thx!

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