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Fax Configuration and Troubleshooting Project

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Abu Hadee
Participant

FAX over VOIP some times can be challenging. Finding the right configuration is sometimes difficult as it can be SCCP, MGCP, SIP or H323 or even combination of multiple protocol. More over, it can be fax pass-through, T38 or Cisco fax relay. 3rd party Fax Server in the IP side makes the situation a bit difficult.

I've created a project to find the working configuration of FAX in different combinations which is running on your network. Submit your topology and requirement along with protocol to use, we will test in lab.  We will submit the configuration along with debug and troubleshooting tips for your reference if something goes wrong.

Click Here to check the progress and submit your requirement. Hope this will help you.

Waiting for your submission.

Thanks

- abu

34 Comments
Abu Hadee
Participant

Thank you all for your topology

So far I have

1. SIP Provider ------SIP ------------CUBE---------H323 -----ATA

2. PSTN--PRI---GW-----MGCP----CUCM----SCCP---VG--fax

3. PSTN--PRI---GW---SIP---CUCM---SCCP---VG-fax

4. PSTN--PRI---GW-----MGCP----CUCM----MGCP---VG--fax

5. PSTN--PRI---GW---SIP---CUCM---MGCP---VG-fax

6. PSTN--PRI---GW-----H323----CUCM----SCCP---VG--fax

7. PSTN--PRI---GW---H323---CUCM---MGCP---VG-fax

8. PSTN-PRI--GW--MGCP--CUCM------h323------cisco fax server (RigthFAX)----MS Exchange

9. PSTN--2xPRI--CME--SCCP--VG224--Fax

10. SIP Provider ------SIP ------------CUBE---------CUCM-----VG2xx--FAX

Keep submitting.

thanks

- abu

raziel78kain
Explorer

Hello,

other scenario could be the following (some of them could be duplicates of the ones that you have written):

  • PSTN--PRI--GW--SIP--CUCM--SCCP--VG20X--fax
  • PSTN--PRI--GW--SIP--CUCM--SIP--VG20X--fax
  • PSTN--PRI--GW--SIP--CUCM--H.323--VG20X--fax
  • PSTN--PRI--GW--SIP--CUCM--MGCP--VG20X--fax
  • PSTN--PRI--GW--H.323--CUCM--SCCP--VG20X--fax
  • PSTN--PRI--GW--H.323--CUCM--SIP--VG20X--fax
  • PSTN--PRI--GW--H.323--CUCM--H.323--VG20X--fax
  • PSTN--PRI--GW--H.323--CUCM--MGCP--VG20X--fax
  • PSTN--PRI--GW--MGCP--CUCM--SCCP--VG20X--fax
  • PSTN--PRI--GW--MGCP--CUCM--SIP--VG20X--fax
  • PSTN--PRI--GW--MGCP--CUCM--H.323--VG20X--fax
  • PSTN--PRI--GW--MGCP--CUCM--MGCP--VG20X--fax
  • PSTN--Q.SIG--GW--MGCP--CUCM--SCCP--VG20X--fax
  • PSTN--Q.SIG--GW--MGCP--CUCM--SIP--VG20X--fax
  • PSTN--Q.SIG--GW--MGCP--CUCM--H.323--VG20X--fax
  • PSTN--Q.SIG--GW--MGCP--CUCM--MGCP--VG20X--fax
  • PSTN--PRI--GW--SIP--CUCM--SIP--ATA187--fax
  • PSTN--PRI--GW--H.323--CUCM--SIP--ATA187--fax
  • PSTN--PRI--GW--MGCP--CUCM--SIP--ATA187--fax
  • PSTN--Q.SIG--GW--MGCP--CUCM--SIP--ATA187--fax
  • PSTN--PRI--CME--SCCP--VG20X--fax
  • PSTN--PRI--CME--SIP--VG20X--fax
  • PSTN--PRI--CME--H.323--VG20X--fax

Regards.

Abu Hadee
Participant

Thank you Raziel.

Jason Ewing
Beginner

Hi Abu,

Here's a couple more scenarios to add to your list....

PSTN--PRI--GW--CME--H323--Cisco Fax Server (RightFax)

PSTN--PRI--GW--H323--CUCM--H323--Cisco Fax Server

Thanks

jay

metalium2007
Participant

hello,

when you put H323 and Rightfax...does rightfax support a gatekeeper environment (register and admission control?)

thanks!

Jason Ewing
Beginner

Hi metalium2007,

We're not using it in a gatekeeper environment, but I did see an H323 gatekeeper supported topology in the BrookTrout FoIP configuration guide.

jay

Abu Hadee
Participant

Thank you all for the fax topology.

I'm going to compile all and start building the lab and configuration. As I go, I'll keep posting it here.

Hope that will be helpful to some of you.

Thank all of you again for participation.

Abu Hadee
Participant

Still working on the lab setup. will start uploading the config soon.

thanks all

Abu Hadee
Participant

Hi All,

Lab setup is complete. And I've run through some scenario. I've started to write the document. I'm wondering if you can provide feedback if this is the right format. I'm making it in word format with proper topology. But I can't add the topology picture here. Please comment

Thank you all

- Abu

Fax Configuration and Troubleshooting Project


Contents

1       Topology 1: H323 to MGCP via CUCM.. 3

1.1 Modem pass-through. 3

1.1.1 Configuration: 3

1.1.2 debug  to run. 4

1.1.3 Call Flow :  Internal fax machines makes call to External Fax. 5

1.1.4 Wrong Configuration  1. 10

1.1.5 Wrong Configuration  2. 11

1.2 T38. 12

2 Topology 2: SIP to MGCP  via CUCM.. 12

2.1Modem Pass-through. 12

2.2 T38. 12

3 Topology 3: SCCP to MGCP  via CUCM.. 12

4 Topology 4: SIP to H323  via CUCM.. 12


1       Topology 1: H323 to MGCP via CUCM

Fax---pstn---pri---PSTN GW-----mgcp ------cucm-------h323--------VG-----fxs----fax

1.1 Modem/Fax pass-through

1.1.1 Configuration:

MGCP Gateway Configuration

ccm-manager mgcp
no ccm-manager fax protocol cisco

mgcp
mgcp call-agent MSCUCMPUB8 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 pass-through voip mode nse
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp package-capability pre-package
no mgcp package-capability res-package
no mgcp timer receive-rtcp
mgcp fax t38 inhibit
mgcp sdp simple
mgcp bind control source-interface GigabitEthernet0/0
mgcp bind media source-interface GigabitEthernet0/0

H323 Gateway Configuration:

voice service voip
modem pass-through nse codec g711ulaw

dial-peer voice 201 voip
destination-pattern 94132035
incoming called-number .
modem pass-through nse codec g711ulaw
session target ipv4:10.66.75.205
codec g711ulaw
fax rate disable
fax nsf 000000
no vad

When configuring  fax or modem pass-through on MGCP Gateway, it only supports modem pass-through. We also need to make sure that T38 is disabled by configuring “mgcp fax t38 inhibit”. Also we need to make sure that fxr-package is not configure at all. That will cause call via MGCP gateway to fail.

On H323 gateway, make sure “fax rate disabled” command is configured. This will stop the Gateway to try fax relay. Some times, if the fax train longer time, it may switch to fax relay pre maturely.  “modem pass-through nse” command can be configured on VOIP dialpeer or under the voip service. Since MGCP gateway only supports NSE based modem pass-through, h323 gateway has to be configured same way.

1.1.2 debug  to run

MGCP Gateway

debug mgcp packet
debug voip vtsp all
debug voip dsm all
debug voip dsmp all
debug voip rtp session named-event

H323 Gateway
debug h225 asn1
debug h245 asn1
debug voip vtsp all
debug voip dsm all
debug voip dsmp all
debug voip rtp session named-event

“debug mgcp packet”, “debug h225 asn1”, and “debug h245 asn1” only to make sure that the voice call established ok. Since this scenario uses modem pass-through, fax switch over will happen via RTP, not via Signalling.

In that scenario, important debugs are “debug voip rtp session named-event”, “debug voip vtsp all”, “debug voip dsmp all” and “debug voip dsm all”

dsm and vtsp debug will show that fax tone is detected and switch over is initated. Fax switchover will be negotiated via NSE and “debug voip rtp session named-event” is one that will show how two gateway is negotatiating.

1.1.3 Call Flow : Internal fax machines makes call to External Fax

Any fax call starts with Audio call. Once audio call is established, Terminating Gateway will initiate the fax switch over either on CED tone or FAX Header depending on if pass-through or realy is configured. Skipping the call establishment debugs. Since the call is outbound, the fax detection will happen in MGCP Gateway first. We need to run vtsp or dsmp debug to see if the GW is detecting fax or modem tone or not. DSP will detect the Modem/Fax tone and pass it to VTSP layer.

*Red colored text is from MGCP GW and  blue color is from VG.

Modem Tone detected by DSP

*Nov 22 22:34:13.343: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_VC_RUNNING, event:E_DSMP_DSP_MODEM_TONE]

*Nov 22 22:34:13.343: //207/6FC797338067/VTSP:(0/0/1:15):-1:1:1/vtsp_dsm_media_event_cb:

   Event=E_DSMP_DSP_MODEM_TONE

*Nov 22 22:34:13.347: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_WAIT_P2P_DONE, event:E_DSMP_CC_MODIFY_REQ

Switch over request is sent to other side via NSE

*Nov 22 22:34:13.351:          s=DSP d=VoIP payload 0x64 ssrc 0x1CE4 sequence 0x42F timestamp 0x46B6B04A

*Nov 22 22:34:13.351:          Pt:100    Evt:192     Pkt:00 00 00  <Snd>>>

*Nov 22 22:34:13.363:          s=DSP d=VoIP payload 0x64 ssrc 0x1CE4 sequence 0x431 timestamp 0x46B6B04A

*Nov 22 22:34:13.363:          Pt:100    Evt:192     Pkt:00 00 00  <Snd>>>

*Nov 22 22:34:13.363:          s=VoIP d=DSP payload 0x64 ssrc 0x1C304B0A sequence 0x929 timestamp 0xE921999C

*Nov 22 22:34:13.363:  <<<Rcv> Pt:100    Evt:192     Pkt:00 00 00

VG received the Swith over request

Nov 22 22:28:28.100:  <<<Rcv> Pt:100    Evt:192     Pkt:00 00 00

Nov 22 22:28:28.104: //-2003088096/9E7FC5338117/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_VC_RUNNING, event:E_DSMP_DSP_REPORT_PEER_TO_PEER_MSG]

Nov 22 22:28:28.104: //107/9E7FC5338117/DSM:(0/0/2):-1/dsmapi_fax_modem_initiation_detected:  current_feature:DSM_FEATURE_VOICE previous_feature:DSM_FEATURE_NONE fallback_status:FALLBACK_NOT_STARTED dsmp event:E_DSMP_DSP_REPORT_PEER_TO_PEER_MSG: TSE_MODEM

Nov 22 22:28:28.104: //107/9E7FC5338117/DSM:(0/0/2):-1/dsmapi_fax_modem_initiation_detected: Event=192 detected

Nov 22 22:28:28.104: //107/9E7FC5338117/DSM:(0/0/2):-1/dsmapi_fax_modem_start: .

Nov 22 22:28:28.112:          s=VoIP d=DSP payload 0x64 ssrc 0x213C4BF5 sequence 0x431 timestamp 0x46B6B04A

Nov 22 22:28:28.112:  <<<Rcv> Pt:100    Evt:192     Pkt:00 00 00

Nov 22 22:28:28.112:          s=DSP d=VoIP payload 0x64 ssrc 0x1E30 sequence 0x929 timestamp 0xE921999C

Nov 22 22:28:28.112:          Pt:100    Evt:192     Pkt:00 00 00  <Snd>>>

Nov 22 22:28:28.124:          s=DSP d=VoIP payload 0x64 ssrc 0x1E30 sequence 0x92B timestamp 0xE921999C

Nov 22 22:28:28.124:          Pt:100    Evt:192     Pkt:00 00 00  <Snd>>>

Nov 22 22:28:28.132:          s=VoIP d=DSP payload 0x64 ssrc 0x213C4BF5 sequence 0x433 timestamp 0x46B6B04A

Nov 22 22:28:28.132:  <<<Rcv> Pt:100    Evt:192     Pkt:00 00 00

Nov 22 22:28:28.144:          s=DSP d=VoIP payload 0x64 ssrc 0x1E30 sequence 0x92D timestamp 0xE921999C

Nov 22 22:28:28.144:          Pt:100    Evt:192     Pkt:00 00 00  <Snd>>>

Nov 22 22:28:28.144: //-2003088096/9E7FC5338117/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_WAIT_P2P_DONE, event:E_DSMP_DSP_GEN_PEER_TO_PEER_MSG_DONE]

ov 22 22:28:28.144: //-2003088096/9E7FC5338117/DSMP:():-1/dsmp_vbd_upspeed: VBD protocol: CC_CAP_MODEM_PASSTHRU_NSE, ecan: 0, switching to codec 0x1, upspeed: 1

Nov 22 22:28:28.148: //107/9E7FC5338117/VTSP:(0/0/2):-1:1:1/vtsp_dsm_peer_event_cb:

   Event=E_DSM_CC_MODIFY_MEDIA_IND

Nov 22 22:28:28.148: //-2003088096/9E7FC5338117/DSMP:():-1/dsmp_send_phase_nse:

VG sending request to switch off ECAN

Nov 22 22:28:28.148: [-2003088096]CNFSM: next_state:S_DSMP_MP_RUNNING_NO_ECAN

Nov 22 22:28:28.152:          s=DSP d=VoIP payload 0x64 ssrc 0x1E30 sequence 0x92E timestamp 0xE9219ADC

Nov 22 22:28:28.152:          Pt:100    Evt:193     Pkt:00 00 00  <Snd>>>

Nov 22 22:28:28.164:          s=DSP d=VoIP payload 0x64 ssrc 0x1E30 sequence 0x92F timestamp 0xE9219ADC

Nov 22 22:28:28.164:          Pt:100    Evt:193     Pkt:00 00 00  <Snd>>>

PSTN received request to switch off ECAN

*Nov 22 22:34:13.407:          s=VoIP d=DSP payload 0x64 ssrc 0x1C304B0A sequence 0x92E timestamp 0xE9219ADC

*Nov 22 22:34:13.407:  <<<Rcv> Pt:100    Evt:193     Pkt:00 00 00

*Nov 22 22:34:13.411: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_RUNNING, event:E_DSMP_DSP_REPORT_PEER_TO_PEER_MSG]

*Nov 22 22:34:13.411: [1793309636]CNFSM: next_state:S_DSMP_MP_RUNNING_NO_ECAN

*Nov 22 22:34:13.415:          s=VoIP d=DSP payload 0x64 ssrc 0x1C304B0A sequence 0x92F timestamp 0xE9219ADC

*Nov 22 22:34:13.415:  <<<Rcv> Pt:100    Evt:193     Pkt:00 00 00

*Nov 22 22:34:13.423:          s=DSP d=VoIP payload 0x64 ssrc 0x1CE4 sequence 0x435 timestamp 0x46B6B27A

*Nov 22 22:34:13.423:          Pt:100    Evt:193     Pkt:00 00 00  <Snd>>>

*Nov 22 22:34:13.431:          s=DSP d=VoIP payload 0x64 ssrc 0x1CE4 sequence 0x437 timestamp 0x46B6B27A

*Nov 22 22:34:13.431:          Pt:100    Evt:193     Pkt:00 00 00  <Snd>>>

*Nov 22 22:34:13.435:          s=VoIP d=DSP payload 0x64 ssrc 0x1C304B0A sequence 0x931 timestamp 0xE9219ADC

*Nov 22 22:34:13.435:  <<<Rcv> Pt:100    Evt:193     Pkt:00 00 00

*Nov 22 22:34:13.455:          s=DSP d=VoIP payload 0x64 ssrc 0x1CE4 sequence 0x439 timestamp 0x46B6B27A

*Nov 22 22:34:13.455:          Pt:100    Evt:193     Pkt:00 00 00  <Snd>>>

ECAN Negotiation Complete

*Nov 22 22:34:13.455: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_GEN_PEER_TO_PEER_MSG_DONE]

*Nov 22 22:34:13.455: [1793309636]CNFSM: cur_container:modem_passthru_container, cur_state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_GEN_PEER_TO_PEER_MSG_DONE

*Nov 22 22:34:13.455: [1793309636]CNFSM: new_container:rsc_running_container

*Nov 22 22:34:13.455: [1793309636]CNFSM: new_container:rsc_main_container

*Nov 22 22:34:13.455: //1793309636/6FC797338067/DSMP:():-1/dsmp_gw_act_ignore:

*Nov 22 22:34:13.455: [1793309636]CNFSM: next_state:CNFSM_NO_STATE_CHANGE

*Nov 22 22:34:13.543: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_MODEM_PHASE]

*Nov 22 22:34:13.543: [1793309636]CNFSM: cur_container:modem_passthru_container, cur_state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_MODEM_PHASE

*Nov 22 22:34:19.863: //207/6FC797338067/DSM:(0/0/1:15):-1/dsmapi_fax_modem_initiation_detected:  current_feature:DSM_FEATURE_MDM_VBD previous_feature:DSM_FEATURE_VOICE fallback_status:FALLBACK_NOT_STARTED dsmp event:E_DSMP_DSP_FAX_TONE

*Nov 22 22:34:19.863: //207/6FC797338067/VTSP:(0/0/1:15):-1:1:1/vtsp_dsm_media_event_cb:

*Nov 22 22:34:25.303: //1793309636/6FC797338067/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_FAX_TONE]

Fax Switch  over Complete

Nov 22 22:28:34.512: //-2003088096/9E7FC5338117/DSMP:():-1/dsmp_exec:

   [state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_FAX_TONE]

Nov 22 22:28:34.512: [-2003088096]CNFSM: cur_container:modem_passthru_container, cur_state:S_DSMP_MP_RUNNING_NO_ECAN, event:E_DSMP_DSP_FAX_TONE

1.1.4 Wrong Configuration 1

mgcp
mgcp call-agent MSCUCMPUB8 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 pass-through voip mode nse
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp package-capability pre-package
mgcp default-package fxr-package
no mgcp package-capability res-package
no mgcp timer receive-rtcp
mgcp sdp simple
mgcp fax t38 inhibit
mgcp bind control source-interface GigabitEthernet0/0
mgcp bind media source-interface GigabitEthernet0/0
mgcp profile default

“mgcp default-packet fxr-package” and mgcp fax t38 inhibit” commands are contradictory to each other. If you have the above two command, call will fail. Because when Callmanager sends call out, it sets the line packet as t38 because call may end up as t38. But the Gateway is not configured for T.38 (mggcp fax t38 inhibit). So it will reject it.

*Nov 23 04:47:31.941: MGCP Packet received from 10.66.75.205:2427--->

CRCX 933 S0/SU0/DS1-1/30@MS-3845-2 MGCP 0.1

C: D0000000017d88cc000000F500000002

X: 1e

L: p:20, a:PCMU, s:off, t:b8, fxr/fx:t38

M: recvonly

R: D/[0-9ABCD*#]

Q: process,loop

<---

*Nov 23 04:47:31.941: MGCP Packet sent to 10.66.75.205:2427--->

510 933 fx: setting cannot be supported

Now the question is why CUCM is sending T.38 when it is not configured? It’s because of the of the “mgcp default-package fxr-package

1.1.5 Wrong Configuration 2

VG Configuration

voice service voip
!
dial-peer voice 201 voip
destination-pattern 94132035
session target ipv4:10.66.75.205
codec g711ulaw
fax rate disable
fax nsf 000000
no vad
!

In this scenario,  call to FAX machine connected to VG will fail. VG will ignore fax tone coming the fax machine.

1.2 T38

2 Topology 2: SIP to MGCP via CUCM

2.1Modem Pass-through

2.2 T38

3 Topology 3: SCCP to MGCP via CUCM

4 Topology 4: SIP to H323 via CUCM

raziel78kain
Explorer

Dear Abu Hadee,

it is a good job so far!

Thanks for your efforts!

Regards.

Dinesh Chovatiya
Beginner

Hi There, 

I have a very strainge problem ,  We have CUCM version  7 and VG224 connected for few physical Faxes .

Currently VG224 is runing on SCCP  and uses  NSE Fax protocol on PRI gateways. to negoicate Fax signals to external networks.   Now currently our client has bought a Online FAX application ( MessageManage)  Which is only supports  T.38 (NO FAX Passthrough )  .

CCM is connected to MessageManage server through  Intercluster trunk (SIP)..  when user tries to sends Fax from Online FAx system to Physical FAX connected to VG224 . FAX fails due to protocol mismatch.

Only possible solution I could think of is converting VG224 to MGCP  and try .   Can any one share IOS config and CCM settings to  convert VG224 from SCCP to MGCP ?

Has any one came accross this issue ?

Abu Hadee
Participant

Hello Dinesh.


thank you for submitting your topology.

So far, I've finished MGCP,SIP and H323 and collecting all t38, fax/modem passthrough inbound outbound.

next, I'll be working on MGCP and SCCP, CUBE. I'll let you know the configuration and debug details.

If any one of you want to have copy of the currently completed topology, please email me with your email. I'll forward.

Thanks

tripbrown
Enthusiast

I have a requirement of making certain vg 224 ports mgcp in order to make them work with a third party FAX server (XMedius 5.x), while leaving the other ports sccp for phone features.

My scenario is VG224 (mgcp port) > CUCM > FAX Server(h.323 gateway) and vice versa.

I can do this if the gateway is dedicated as mgcp but I read where you could have dual protocol VG224s registered as both sccp and mgcp.  I have done that but the mgcp port is dead.  sccp is working.

Does anyone have a configuration document or example for this?

Thanks

Abu Hadee
Participant

Hello All

I've uploaded the initial draft of the document in the community. It can be found on

https://supportforums.cisco.com/servlet/JiveServlet/downloadBody/14593-102-1-33573/CSC%20Fax%20Document%201st%20Draft.pdf

Sorry for the delay as it was many topology, plus the holidays. Not all topologies are completed. But I'll keep adding while publish the draft which may help some of you.

I'll really appreciate if you can send me your comments.

Thank you

- abu

mabucham7
Beginner

Hello to ALL

   Now with CCA 3.0 fax configuration is enabled but can someone plz tell us, the procedure and if it will work without interfering from CLI

Regards

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