On 01/15/2012 08:14 PM, Louis Carreiro wrote:
Hey all!
I've been banging my head against the wall for a while (almost 18 hours
today alone) with this one... I migrated our incomming T1's from the
Option 11 to our Asterisk box this morning. We have 1 local T1 and 2
long distance T1's. The local T1 went over with out a hitch. The problem
is with my 2 long distance T1's. The switch on the other end is a DMS250
I'm told so I set Asterisk to DMS100 and got the timing, framing, etc
all set. Well, the D channels came up so thats good. I started getting
dropped calls every once in a while. I did a debug on the spans and saw
the following:
PRI Span: 3
PRI Span: 3 < Protocol Discriminator: Q.931 (8)  len=40
PRI Span: 3 < TEI=0 Call Ref: len= 2 (reference 857/0x359) (Sent from
originator)
PRI Span: 3 < Message Type: SETUP (5)
PRI Span: 3 < [04 03 80 90 a2]
PRI Span: 3 < Bearer Capability (len= 5) [ Ext: 1  Q.931 Std: 0  Info
transfer capability: Speech (0)
PRI Span: 3 <                              Ext: 1  Trans mode/rate:
64kbps, circuit-mode (16)
PRI Span: 3 <                                User information layer 1:
u-Law (34)
PRI Span: 3 < [18 04 e9 80 83 08]
PRI Span: 3 < Channel ID (len= 6) [ Ext: 1  IntID: Explicit  Other(PRI)
Spare: 0  Exclusive  Dchan: 0
PRI Span: 3 <                       ChanSel: As indicated in following
octets
*PRI Span: 3 <                       Ext: 1  DS1 Identifier: 0
*PRI Span: 3 <                       Ext: 1  Coding: 0  Number
Specified  Channel Type: 3
PRI Span: 3 <                       Ext: 0  Channel: 8 Type: CPE]
PRI Span: 3 < [20 02 00 e2]
PRI Span: 3 < Network-Specific Facilities (len= 2) [ Toll Free MEGACOM ]
PRI Span: 3 < [6c 0c 21 83 37 32 37 34 30 33 34 30 37 34]
PRI Span: 3 < Calling Number (len=14) [ Ext: 0  TON: National Number
(2)  NPI: ISDN/Telephony Numbering Plan (E.164/E.163) (1)
The key part is the "*Ext: 1  DS1 Identifier: 0*" part. That's when
calls fail. Right now, all calls are coming in on span 3 and want to
talk to Identifier 0 (span 2). If a call comes in on span 2 and requests
"*Ext: 1  DS1 Identifier: 1*", it fails. I called Verizon and asked them
what was going on. Turns out, its configured as a trunk group. The tech
mentioned that I need to figure out how to set my identifiers on the
group and I should be good to go. I've done a ton of research about
chan_dahdi.conf and dahdi-channels.conf and I think the answer is trunk
groups.
I tried configuring a trunkgroup and set the primary dch to 24 and the
bdch to 72 and then then spanmap'ed span 2 and 3 into group 1 (e.g.
2,1,0 and 3,1,1) but I don't see anything when I do a "dahdi show
channels" or a "pri show spans" or a "pri show channels", not even the
channels not in the group. If I delete the trunkgroup, all three
commands return all the channels.
I'm just curious if I'm going down the right path with trunkgroups for
this or if there is something else to take care of the DS1 Identifier issue.

You are, but your configuration attempt doesn't make much sense; it sounds like you created an invalid configuration, and when chan_dahdi attempted to load it, it dropped the whole thing (and you should have seen errors on the console/logs).

You have three physical spans:

span 1 is channels 1-24, and is your local group.
span 2 is channels 25-48, and is your first span of the LD group.
span 3 is channels 49-72, and is your second span of the LD group.

If you want to setup NFAS for this configuration, you'd do this:

* Create a trunkgroup, with channel 48 as the primary D-channel, and channel 72 as a backup D-channel (if that's how your NFAS group is configured... many NFAS groups only have one D-channel).

* 'spanmap' span 2 into that trunkgroup as logical span 1.
* 'spanmap' span 3 into that trunkgroup as logical span 2.

To keep your configuration consistent, you can also configure your first span as a trunkgroup, even though it only has one span in it:

* Create a trunkgroup with channel 24 as the primary D-channel, and no backup D-channels.

* 'spanmap' span 1 into that trunkgroup as logical span 1.

The trunkgroup numbers you assign really aren't important, as long as they are unique; they are never communicated over the ISDN signaling, only the logical span numbers are.

--
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: [email protected] | SIP: [email protected] | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org

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