Summary:ASTERISK-06374: Setup Message
Reporter:Markus Monka (mmonka)Labels:
Date Opened:2006-02-20 03:53:42.000-0600Date Closed:2006-03-31 16:41:57.000-0600
Versions:Frequency of
Description:Setup: Asterisk with TE410P. Span 1-3 are configured for pri_cpe and connected to an Siemens EWSD (pri_net).

Szenario: SIP -> Asterisk -> TE410P -> EWSD
         INVITE ->       -> SETUP

While initialising a call to pstn, asterisk sends a Setup like this:

> Call Ref: len= 2 (reference 15072/0x3AE0) (Originator)
> Message type: SETUP (5)
> [04 03 80 90 a3]
> Bearer Capability (len= 5) [ Ext: 1  Q.931 Std: 0  Info transfer
capability: Speech (0)
>                              Ext: 1  Trans mode/rate: 64kbps,
circuit-mode (16)
>                              Ext: 1  User information layer 1: A-Law
> [18 03 a9 83 9b]
> Channel ID (len= 5) [ Ext: 1  IntID: Implicit, PRI Spare: 0, Exclusive
Dchan: 0
>                        ChanSel: Reserved
>                       Ext: 1  Coding: 0   Number Specified   Channel
Type: 3
>                       Ext: 1  Channel: 27 ]
> [28 0e 53 74 65 66 61 6e 20 53 63 68 6d 69 64 6c]
> Display (len=14) ËF@ðpG@
                          ?º'ÒE@Ø@ÈF@>[ Test Test ]
> [6c 0c 21 81 39 31 32 32 31 37 31 33 33 36]

Having a look to the specs, i would say, it is not allowed to send an
DISPLAY element as an TE(CPE) in SETUP Messages.

The EWSD has a limit of 5 Errors per Minute. After sending 5 SETUP Messages
with Display Element, the EWSD blocks the channel for a short interval.

So we removed Q931_DISPLAY in 'setup_ies' in 'libpri/q931.c' and
now everything is fine.

Comments:By: Matthew Fredrickson (mattf) 2006-02-21 09:13:46.000-0600

I have not read any documentation indicating that this IE should not be sent.  If you can provide a reference, as well as your switchtype that you are working against (and have it set to in zapata.conf), I'll take a look to see if we should add some code to keep it from being sent for that switchtype.  Otherwise, the non intrusive way to work around it is to set your callerid name variable to nothing before you do a Dial() in your dialplan.

By: Markus Monka (mmonka) 2006-02-21 10:00:36.000-0600

I allready tried out to leave the callerid name empty, but it did not work.

I have a german Book called: "ISDN - die Technik", there I found the Information
on not sending the Display.

I´ll ask the Carrier for the detailes of the Switchtype and find some more
information on the specs.

By: Markus Monka (mmonka) 2006-02-22 02:43:02.000-0600

For my understanding, we have configured our Setup for beeing USER (pri_cpe).
The Switch is an Siemens EWSD (pri_net); switchtype is euroisdn.

So our Szenario is sending Messages from User -> Network (u->n).
Looking in ETS 300 102-1 31.16 (SETUP) Display is an optional Element which
may be included the otherway round (n->u). That is the reason why the
ESWD shuts down the channel after receiving 5 SETUPS per Minute with Display IE.

By: Matthew Fredrickson (mattf) 2006-03-31 16:41:46.000-0600

Fixed in trunk