1 (866) 885-5606

Legacy Fax into Modern Business Intelligence

To make forum posts, you must be a registered user of AllAboutFoIP.com.

Username   Password       Forgot your password?  Forgot your username?  Create an account

** FORUM for AllAboutFoIP.com™ **

The FoIP Forum is now live and active.  Register and be one of the first to start a forum thread.  FoIP experts frequent the forum regularly to post replies.

This forum does not accept backlink signature lines in forum posts. SPAMMERS KEEP OUT.

SIP Trunking Providers with T.38 Support

SIP Trunking Providers with T.38 Support

I'm aware that both Global Crossing,BroadVox and Broadview Networks provide T.38 FoIP and have interoperability support with Dialogic Brooktrout's SR140 T.38 solution.  What other SIP Trunking carriers state actual T.38 support and have been tested in the field?  In addition, what capabilities and/or limitations do each one of them have (V.17, v.34, ECM, Max Rate, etc)?

BadFat
President, Satori Solutions
ranks
useravatar
Offline
19 Posts
Administrator has disabled public posting

Re: SIP Trunking Providers with T.38 Support

Chris:  The topic of SIP Trunking and Fax over IP (FoIP) compatibility is quite important given the momentum towards IP VoIP and Data services from the carriers. 

I met with some SIP industry leadership last week, and seemed to detect that many carriers have neglected the importance of this compatibility, maybe to the tune of some denial, or maybe hoping the issue can be delayed.  In general, you have to applaud organizations such as Global Crossing and Broadvox for taking the leap. 

Generally speaking, other carriers may at times seem to apppear stable with FoIP and SIP trunking, and at other times it is problematic.  It has alot to do with the series of equipment and networks the traffic passes through, Border Session Controllers, Switching Infrastructures, Gateways, VoIP trunking solutions et al , and so forth.  For example, one common carrier based solution is provided by Sonus Networks, which I believe is heavily used by AT&T, and maybe Qwest, and others.  In some cases, such equipment may not have been upgraded throughout the network, even though the requisite equipment providers may have updated their solutions and firmware offerings to be compatible (this is what I am told, but it needs further research).  I spoke to the CEO who provides T.38 support for Sonus, and was assured it was up to date and compatible.  In other cases, I understand that their are various relationships among carriers to share networks, so for instance if a long distance call is passed to equipment off-carrier, then that equipment may not be compatible, even though the host network could be.  So I believe the general issue is that you need a carrier that can guarantee a call on their service will fully traverse a FoIP friendly network, particularly a network that is moving voice traffic as IP.

One final note, we have seen some very major carriers swear up and down that they can handle the faxes without issue, and many of their reps have no clue (because to them it seems logical, as they do not know how complicated a fax data call can be over IP).  This is apparent even when a customer is given a PSTN hand off (e.g. a regular voice T1, not a SIP trunk).  What happens on the back end, however, is that the traffic can be onramped to an IP network, maybe even basic SIP protocols, which thus possibly impairs fax call reliability.  With high volume, and/or diversion of traffic, the error rates go up, and carrier technicians are seemingly trained to analyze call success from only one perspective, thus blaming CPE (Customer Premise Equipment) even though it is truly a carrier issue.  This issue may not just result in IP traffic symptoms of jitter and latency not preconditioned using T.38, but more importantly, it could be that fax signalling and standards (like ECM) are marginalized by SIP protocols not inherently designed to interpret and pass these signals.

We do plan as part of the AllAboutFoIP initiative to bring higher visibility to this issue, to incentivize carriers to scale up adoption, and to acknowledge the carriers who take a leadership role on supporting these new standards.  More to come.

srileyotgt
CEO @ www.otgt.com
ranks
useravatar
Offline
31 Posts
Administrator has disabled public posting

Re: SIP Trunking Providers with T.38 Support

To respond to a few of the questions: Nearly all of the large-footprint IP carriers use the GSX tandem gateways from Sonus.  For some reason, early releases of the GSX did not enable ECM support, but I understand that it is now available as an upgrade to these carriers.  But, as we know, it's difficult to overestimate the inertia of carrier networks, so it will take some time for the newer releases to work their way through the infrastructure.  And, of course, this also applies to support for V.34, which requires T.38 version 3 and the V.34 fax modem.  Commetrex, the primary vendor of FoIP technologies to the telecom-equipment OEM, began shipping T.38 V3 support two years ago.  So you will see additional delays as the TEMs schedule equipment upgrades that add the MIPS and memory resources to support V.34, integrate the technology, release to the field, and then propagate its way throughout the carrier infrastructure.

So, today, you will mostly see carrier support for T.38 V0, which means V.17, perhaps, but probably not ECM.

mike coffee
CEO
ranks
useravatar
Offline
1 Posts
Administrator has disabled public posting

Re: SIP Trunking Providers with T.38 Support

This is a good white paper for narrowing down specific SIP Trunk carriers where you want to support fax in a reliable way.  Ironically, most carriers (including major carriers) handle fax very poorly over SIP trunks.  However, there are exceptions and certain carriers with very high reliability and success.

Here is the white paper: http://www.allaboutfoip.com/blog/entry/ … r-SIP.html

srileyotgt
CEO @ www.otgt.com
ranks
useravatar
Offline
31 Posts
Administrator has disabled public posting

Board Info

Board Stats:
 
Total Topics:
99
Total Polls:
0
Total Posts:
44
Dormant:
User Info:
 
Total Users:
13834
Newest User:
lanorawearne708
Members Online:
0
Guests Online:
131

Online: 
There are no members online

Forum Legend:

 Topic
 New
 Locked
 Sticky
 Active
 New/Active
 New/Locked
 New Sticky
 Locked/Active
 Active/Sticky
 Sticky/Locked
 Sticky/Active/Locked
Concord Technology TargetFax FoIP Faxing Solutions cisco_logo Microsoft FoIP Fax Parnter
etherfax-180px DiaLogic FoIP Faxing Solutions Faxcore FoIP Faxing Solutions One Touch Global Technologies FoIP Faxing Solutions
babyTEL-logo_BLUE-Sml Open Text FoIP Faxing Solutions XMediusFAX FoIP Faxing Solutions logo-kofax