|Summary:||ASTERISK-18632: Limit PRI channel re-selection to same group in span|
|Reporter:||Kris Shaw (shawkris)||Labels:|
|Date Opened:||2011-09-26 12:44:46||Date Closed:||2017-12-19 09:43:35.000-0600|
|Versions:||18.104.22.168 13.18.4||Frequency of|
|Environment:||DAHDI 22.214.171.124, LibPRI 1.4.12, Asterisk 1.8.7||Attachments:||( 0) stuck-channel-01.txt|
( 1) stuck-channel-cause-01.txt
|Description:||Due to other yet to be resolved issues, channels between Asterisk and our PBX become stuck. This causes chan_dahdi to attempt to re-negotiate the channel. However, on our PBX the channels are split into two groups, with matching groups on Asterisk in different contexts. Calls coming into Asterisk on channels on one group are re-negotiated into another group in a different context, causing the call to fail. This is due to the way chan_dahdi always looks for free channels working down from the highest in the span.|
|Comments:||By: Kris Shaw (shawkris) 2011-09-26 12:48:38.561-0500|
Extract from chan_dahdi.conf
By: Kris Shaw (shawkris) 2011-09-26 13:15:04.295-0500
For reference, stuck-channel-cause-01.txt contains the last message that caused channel span 2 0/1 to get stuck
By: Richard Mudgett (rmudgett) 2017-12-19 09:43:01.582-0600
Features requests without patches are not accepted through the issue tracker. Features requests are openly discussed on the mailing lists, forums, and IRC . Please see the Asterisk Issue Guidelines  for more information on feature request and patch submission.
What the reporter is trying to do is not typical and likely not privisionable from telcos. The link in question is between their PBX and Asterisk.
What the reporter wants depends on some things being true that only controlling both ends can be guaranteed:
# Both ends must know the grouping of channels.
# All calls *must* have a preferred or exclusive B channel selected when the SETUP is sent. Otherwise, the receiving end will not know to which call group the call belongs if it has to pick an alternate channel. Q.931 does not require that a B channel be identified in the SETUP.
Currently, chan_dahdi can select channels for outgoing calls by groups. (Dial(DAHDI/g1/5551212))
For incoming calls, chan_dahdi has no way to configure how to select channels when needed. It always picks the highest available channel on the span. See ASTERISK-18405 where this was first brought up.