[cisco-voip] T.38 with VG248's and MGCP PRI Gateways

[Erick B.]

Still having intermittent problems with this.

Have been working with Cisco with out much changes. I am going to this
location next week so can get captures then.

So far have tried every combination of MGCP settings with same
results, hit and miss.

Need protocol-based MGCP T38 for connection to SIP FAX server (First
Class), and have VG248s set for passthrough mode (Fax Relay disabled).

Inbound FAX:s work fine (very few failures) but outbound FAX calls
from VG248-attached FAX machines are the big problem. They are brother
FAX machines and they do not have any settings or switches to change
baud rate, disable ECM, disable SuperG3, etc.

I am taking a VG224 out with me to use along side the VG248 and move
the FAX machines over to VG224. Going to set the 224 up as MGCP same
as PSTN MGCP gateways since SCCP only supports NSE based T38 (same as
VG248) from my reading of the cisco documentation and a couple posts
on cisco forums. So it looks like SCCP is limited to NSE based T38 if
both can only do NSE (just a guess here).

The VG248s and passthough worked fine on CCM 4.1 but has been hit and
miss ever since move to CUCM 8.02. Gateways did not change. They are
also having issues fax'ing between FAX machines on the same VG248 and
they did not have those issues on older CCM version.


On Wed, Oct 6, 2010 at 9:55 AM, Chris Clouse <Chris.Clouse at cdw.com> wrote:
> If you are still having trouble, send a diagram of the call flow for a working vs non-working fax and a Wireshark capture.
>
> Christopher  Clouse
> Network Voice Engineer
>
> CDW Advanced Technology Services
> 7145 Boone Ave N, Suite 140, Brooklyn Park, MN 55428
> Single Number Reach: 763.592.5887
> chris.clouse at cdw.com
>
>
>
> -----Original Message-----
> From: Erick B. [mailto:erickbee at gmail.com]
> Sent: Tuesday, October 05, 2010 11:52 PM
> To: Chris Clouse
> Cc: voip puck
> Subject: Re: [cisco-voip] T.38 with VG248's and MGCP PRI Gateways
>
> Yea, have tried these and combinations and still have hit and miss FAXs. Where some FAX machines can call most numbers fine but not others.
>
> Let me try to take off the t38 force and leave fxr-package as not default and see if that makes a difference (thats about the only combo I haven't tried yet).
>
> No ATAs, just FAX's off of VG248s.
>
> On Tue, Oct 5, 2010 at 9:41 PM, Chris Clouse <Chris.Clouse at cdw.com> wrote:
>> I think this will do what you are looking for.  Be aware that mgcp fax t38 gateway force will break ATA's in your environment.
>>
>> mgcp package-capability fxr-package
>> mgcp default-package fxr-package
>> no mgcp t38 fax inhibit
>> no ccm-manager fax protocol cisco
>> no mgcp fax t38 ecm
>> mgcp fax t38 gateway force
>>
>> Christopher  Clouse
>> Network Voice Engineer
>>
>> CDW Advanced Technology Services
>> 7145 Boone Ave N, Suite 140, Brooklyn Park, MN 55428 Single Number
>> Reach: 763.592.5887 chris.clouse at cdw.com
>>
>>
>>
>> -----Original Message-----
>> From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Erick B.
>> Sent: Tuesday, October 05, 2010 4:52 PM
>> To: voip puck
>> Subject: [cisco-voip] T.38 with VG248's and MGCP PRI Gateways
>>
>> Hi,
>>
>> Anyone ever do T.38 faxing with VG248s and MGCP PRI gateways?  Have client that needs to use T38 for a SIP FAX Server they have, but outbound calls to PSTN from Brother FAX Machines attached to VG248s are intermittent.  Sometimes they work, sometimes they don't. The Brother FAX machines have no way to change Baud rate or ECM settings, etc. They had no problems with passthrough (before the FAX Server was upgraded to SIP).
>>
>> Incoming FAX's work fine (a majority - very little issues reported).
>> Most of these go to FAX server and some go directly to the FAX machines on the VG248's.
>>
>> The VG248 ports are set to T.38 peer to peer, and we've tried various MGCP T38 settings on the gateway with TAC's help but still having problems with outbound FAXs.
>>
>> Tried setting gateways to force t38 (mgcp fax t38 gateway force), tried removing the fxr-package as default (not needed for VG248 per TAC), and set the ls and hs redundancy settings to 0 (VG248 doesn't support redundancy), tried with with mgcp fax rate set to 9600 baud, ECM off on MGCP gateway, etc. Reset MGCP with these changes each time.
>>
>> Anyone know how to disable VG248 from using Passthrough mode? The port is set to T.38 peer to peer but when I try changing the Passthrough setting to "voice only - no passthrough" then no FAXs work at all with the FAX machine attached to the VG248 port (I bounced the port after the change also).
>>
>> Call Manager version is 8.02 with latest 12.4.24T IOS on gateways.
>>
>>
>> Ideas anyone?
>>
>> Thanks, Erick
>> _______________________________________________
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>> cisco-voip at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-voip
>>
>