asterisk users - Aug 2007 - compatibility of PRI Two B channel transfers TBTC/2BTC

Hello,

A client has asked for Two B channel Transfer capability (known as
TBCT or 2BCT, similar to other features such as ECT, RTL and Q,SIG
Path Replacement) in a new Asterisk system and so I researched the
capability and came up with quite a few gaps in documentation.

Matt Florell wrote:
> Hello,
>
> A client has asked for Two B channel Transfer capability (known as
> TBCT or 2BCT, similar to other features such as ECT, RTL and Q,SIG
> Path Replacement) in a new Asterisk system and so I researched the
> capability and came up with quite a few gaps in documentation.
>
> >From what I've gathered, the official Digium statement is that is
> works with DMS100 only, and only in Asterisk 1.4.X :
> http://kb.digium.com/entry/26/140/
>
> Although in a bugtracker posting with a patch from over two years ago,
> Matt Fredrickson from Digium says that it works with 5ESS under
> Asterisk 1.2.X:
> http://bugs.digium.com/view.php?id=3554
>
> There are also bounties and claims of this feature working on NI2
> protocol(although no patches posted) on the voip-info.org Wiki:
>
http://www.voip-info.org/wiki/view/Asterisk+bounty+PRI+2B+channel+transfer+for+NI2+PRI+line
>
http://www.voip-info.org/wiki/index.php?page=Asterisk%20bounty%20PRI%202B%20channel%20transfer
>
> As for actually using this feature, you apparently need to add the
> following lines to the zapata.conf section that you want to be able to
> use 2BCT:
> facilityenable = yes
> transfer=yes
>
> To execute the transfer, you need to use the "Transfer" cmd
within Asterisk:
> http://voipinfo.org/wiki/view/Asterisk+cmd+Transfer
>
> And according to this post, you can only do 2BCT transfers if the
> first call is inbound:
> http://www.mail-archive.com/asterisk-dev at lists.digium.com/msg25131.html
>
>
> Does 2BCT work with DMS100 and 5ESS right now?
>
> Are there people using this in production right now that can shed some
> more light on exactly how they are using it, and executing the
> transfers?
>
> Any input would be greatly appreciated.
>
> Thanks,
>
> MATT---
>
>
>   
Sounds like the early days of Asterisk. 

Do us all a favor, after you have tried everything, pulled out your 
hair, banged your head, had a breakthrough and solved the issue (jumping 
up and down excitedly saying "YES, YES YES", post your experience to
the
wiki, and or reply to this thread.

Thanks,
Steve

Matt Florell wrote:
> Hello,
> 
> A client has asked for Two B channel Transfer capability (known as
> TBCT or 2BCT, similar to other features such as ECT, RTL and Q,SIG
> Path Replacement) in a new Asterisk system and so I researched the
> capability and came up with quite a few gaps in documentation.
> 
> From what I've gathered, the official Digium statement is that is
> works with DMS100 only, and only in Asterisk 1.4.X :
> http://kb.digium.com/entry/26/140/
This definitely works.  I wrote it and tested it myself.
> 
> Although in a bugtracker posting with a patch from over two years ago,
> Matt Fredrickson from Digium says that it works with 5ESS under
> Asterisk 1.2.X:
> http://bugs.digium.com/view.php?id=3554
There's an implementation I scrubbed out a couple of years ago, but I 
think there was a bug in it that I was not able to fix.  When push came 
to shove, and I needed a switch to debug it on (and when I had more time 
to work on it), nobody offered switch access so that I could debug it. 
So I don't think it is working right now.
> There are also bounties and claims of this feature working on NI2
> protocol(although no patches posted) on the voip-info.org Wiki:
>
http://www.voip-info.org/wiki/view/Asterisk+bounty+PRI+2B+channel+transfer+for+NI2+PRI+line
>
http://www.voip-info.org/wiki/index.php?page=Asterisk%20bounty%20PRI%202B%20channel%20transfer
Yeah, well, they're really old :-)  Try getting a hold of the authors.
> 
> As for actually using this feature, you apparently need to add the
> following lines to the zapata.conf section that you want to be able to
> use 2BCT:
> facilityenable = yes
> transfer=yes
Yes, that is correct.
> 
> To execute the transfer, you need to use the "Transfer" cmd
within Asterisk:
> http://voipinfo.org/wiki/view/Asterisk+cmd+Transfer
This is incorrect.  If you have transfer=yes and facility=yes in 
zapata.conf for both channels, and both channels meet all the other 
criteria for TBCT (on the same PRI, and a few other switch dependent 
rules), when a native bridge is attempted, it automatically attempts to 
pass the calls up to the upstream switch.  If it is successful, your 
calls will remain up, but you will get a hangup in asterisk on both calls.
> 
> And according to this post, you can only do 2BCT transfers if the
> first call is inbound:
> http://www.mail-archive.com/asterisk-dev at lists.digium.com/msg25131.html
That's a rule only for DMS100.
> 
> 
> Does 2BCT work with DMS100 and 5ESS right now?
Last I heard (a couple of years ago) it doesn't.
> Are there people using this in production right now that can shed some
> more light on exactly how they are using it, and executing the
> transfers?
I hope I answered your questions :-)

-- 
Matthew Fredrickson
Software/Firmware Engineer
Digium, Inc.