Summary:ASTERISK-01299: libpri does not support AT&T feature "Dialed Number Preferred"
Reporter:mschaefe (mschaefe)Labels:
Date Opened:2004-03-26 07:06:24.000-0600Date Closed:2011-06-07 14:04:43
Versions:Frequency of
Description:For multiple inbound numbers assigned to a PRI (the thing you might do if you were running a PBX off of one or more PRI's) AT&T adds "Dialed Number Preferred" to the PRI.  Based on my initial work with it, it provides a different IE than libpri expects to pass the dialed number.  Like SDN marking, I can make changes to libpri, but I need someone to help me understand how to make those configurable in a file and not require a recompile of the libpri code.  Cisco 2600's recognize this option out of the box without any reconfiguration, so we may want to recognize it 100%.  I'm not sure.

I can volunteer to submit a simple patch once I get it working, but I can't guarantee that the patch won't break PRI's without this feature.
Comments:By: Brian West (bkw918) 2004-03-26 17:04:29.000-0600

same with your last patch we can ifdef those features out or in.. also join #asterisk-dev on freenode or #asterisk and you can talk about it with other developers.

By: Brian West (bkw918) 2004-04-18 01:56:19

Is this an standard or some sick AT&T twist?

By: mschaefe (mschaefe) 2004-04-19 11:23:37

This appears to be standard.  I'll talk about the root of the issue and you can look at the code I submitted under SDN marking, but I've not gotten approval to disclaim it.  Grrr.

Here's the issue with SDN Marking.  SDN Marking is the implementation of the Network-Specific Facility Information Element.  I believe the specific facility codings are up to the providers, but AT&T has a couple.  I know that Cisco incorporates these features, so they at least have broad acceptance.

By: mschaefe (mschaefe) 2004-04-19 11:50:17

It looks like Dialed Number Preferred itself is not the problem.  Apparently, what happens with DNP is that they also code information about the caller.  So, what happens is that there is IE 0x96 - Locking Shift to CodeSet 6, followed by an IE 001 in codeset 6.  That IE tells you the technology the call originated from - POTS, Cell Network, Cell Roaming, etc.

What Asterisk is doing is ignoring the switch to CodeSet 6, and then IE 0x01 is considered a "mandatory" IE that Asterisk is not recognizing.  Therefore the call is rejected.

Also, as a note of interest.  The Cisco 2600 I test against also does not recognize that second IE, but it reports it as a Change Status, which it is not.

By: twisted (twisted) 2004-04-30 13:21:15

Is this going to go anywhere?

By: mschaefe (mschaefe) 2004-05-03 10:05:52

It may take me a few months to get the patch disclaimed, but I have a partial fix to this that has worked in our lab for the past month without problems.

By: Mark Spencer (markster) 2004-05-25 01:37:46

Since this can't really be disclaimed in its current form i'm going to go ahead and suspend this one.

By: Paul Cadach (pcadach) 2004-06-29 13:27:21

Reminder sent to markster

As I understood the problem was with (at the moment of reporting) invalid CodeSet 6 IE parsing. Now it is supported to I believe this ticked could be closed, not suspended.