asterisk users - Feb 2007 - Asterisk H.323, Cisco IOS Gatekeeper(s) intra-zone call routing and TETRA

Stephan,

Ok, I'll re-state the problem...

I have two devices that I want to talk to each other:

1. an Asterisk PBX
2. a Damm Cellular TETRAFLEX digital radio system (www.damm.dk)

both devices are effectively "gateways" because they have many
subscribers
behind them.

The Damm Cellular system controller is based on Windows-XP Embedded and its 
sub-systems used the OpenH323 driver/libraries. Officially Damm supports 
only H.323 connections and only to Innovaphone products such as IP phones 
and ISDN gateways - I want to connect it to VoIP and Asterisk.

The Asterisk box is FC6, Asterisk 1.2.14, ooh323 from 
Asterrisk-Addons-1.2.5 - using ooh323 because the others depend on OpenH323 
libraries which are problematic (see below)

In the Damm Cellular system H.323 configuration use of a H.323 gatekeeper is 
mandatory, not optional :o(

So, how to join the Damm system to an Asterisk box?  Some ASCII art:

                                    192.168.1.0/24
              --------------------------------------------------------
                    |                     |                     |
               192.168.1.7           192.168.1.6           192.168.1.5
                    |                     |                     |
             ----------------      ----------------      ----------------
             | Damm Tetra   |      | Cisco Router |      | Asterisk PBX |
             | (OpenH323)   |      | GateKeeper   |      | (ooh323)     |
             | H323ID=DAMM  |      | Zone=THORCOM |      | H323ID=PABX  |
             | Nos=817XXXX  |      |              |      | Nos=810XXXX  |
             ----------------      ----------------      ----------------

I started on the hope of using the GNU GateKeeper 2.2.5 but ran into lots of 
problems on my Fedora Core 6 box with libraries, incompatibilities, 
compilation errors, the fact that OpenH323 appears deprecated in favour of 
Opal, etc. and in the end gave up and switched to a spare Cisco 2621XM 
router with c2600-jsx-mz.123-22.bin image which includes the Cisco H.323 
Gatekeeper...

The I started reading the documentation and got entirely confused :o( 
Nearly all of Cisco's examples show one gateway connected to one gatekeeper 
in a local zone and may routes to other zones that are 'remote', ie. WAN
connected and all the traffic flow/examples appeared to be for this.

What I wanted/need is two gateways inside a single zone, and hence 
intra-zone calling (not inter-zone) - confusion continued - because of the 
talk of "technology prefixes" like "1#" and "2#"
and "8#" ...

I already have a number plan/dial plan in the form 8EEXXXX where all of our 
Asterisk exchanges have a two-digit exchange number, like "810",
"820",
"867" etc. and we use four-digit extensions like 2001...2999 for
phones,
6XXX for services like voicemail, etc. which makes it easy for work 
collegues, friends and family to all have Asterisk exchanges and perform 
inter-exchange dialling [yup, we have a hub/router asterisk box with loads 
of IAX2 connections and no phones]

I assigned 817XXXX to the Damm TETRA system and my local PBX is already 
810XXXX and is the only "route" to the rest of my 8EEXXXX number plan
and to
the outside world.

I could see how the technology prefix could be used to route calls in the 
H.323 context - for example i could declare Asterisk as technology 1# and 
Tetra as 2# but while it is easy to add a leading 2# to dialled numbers 
leaving the Asterisk box I could find no way to tell either the Damm system 
or Asterisk which technology prefix to register -- this functionality 
appears to be missing.

So, the question was - "how to route calls intra-zone without technology 
prefixes" - back to the problem that there were plenty of examples of cross
site/inter-zone configurations but little about intra-zone - then last nigh 
I stumbled on the phrase "in the updated version of the 'zone
prefix'
command..." in Cisco IOS documentation, so I went and googled for
"cisco ios
command reference zone prefix" and I think I may have found what I need...

So, I have the Damm system and Asterisk system both registered with the 
Cisco GateKeeper as gateways:

router-h323-gw#show gatekeeper endpoints
                    GATEKEEPER ENDPOINT REGISTRATION
                    ===============================CallSignalAddr  Port 
RASSignalAddr   Port  Zone Name         Type    Flags
--------------- ----- --------------- ----- ---------         ----    -----
192.168.1.5     1720  192.168.1.5     13030 THORCOM           UNKN-GW
    H323-ID: PABX
    H323-ID: ASTERISK
    E164-ID: 100
    Voice Capacity Max.=  Avail.=  Current.= 0
192.168.1.7     1720  192.168.1.7     1085  THORCOM           UNKN-GW
    H323-ID: DAMM
    Voice Capacity Max.=  Avail.=  Current.= 0
Total number of active registrations = 2



I've added the following zone prefixes to the Cisco gatekeeper config:

!
gatekeeper
 zone local THORCOM int.thorcom.com 192.168.1.6
 zone prefix THORCOM 0* gw-priority 5 PABX        ! outside calls to PSTN 
etc
 zone prefix THORCOM 1* gw-priority 5 PABX        ! calls to 
information/operator
 zone prefix THORCOM 2... gw-priority 5 PABX        ! short calls to 
extension numbers
 zone prefix THORCOM 817.... gw-priority 10 DAMM    ! calls to TETRA
 zone prefix THORCOM 8...... gw-priority 5 PABX        ! calls to rest of my 
number plan
 zone prefix THORCOM 9.. gw-priority 10 PABX        ! emergency calls 
911/999
 gw-type-prefix 1#* default-technology
 no shutdown
!


... so I think this should route the calls between the gateways...?



Mike



----- Original Message ----- 
From: "Stephen Bosch" <posting@vodacomm.ca>
To: "Michael J. Tubby G8TIC" <mike.tubby@thorcom.co.uk>
Sent: Monday, February 05, 2007 7:51 PM
Subject: Re: [asterisk-users] Help sought: Asterisk H.323, Cisco IOS 
Gatekeeper(s) intra-zone call routing and TETRA

> Michael J. Tubby G8TIC wrote:
>> I can see how this be acheived if I had two Gatekeepers and two zones,
>> say one called "tetra" and one called "asterisk" by
using zone prefixes
>> and "zone remote" to route between them and putting one of
the gateways
>> on each of the Gatekeepers - but this appears to be over-the-top for
>> what I want, ie. two gateways on the same Gatekeeper at the same site,
>> in the same zone, routing calls between them...
>>
>>
>> Can anyone give me a clue where to go next with this?
>
> Oof... that was a lot to process.
>
> It's been a long time since I worked with H.323, but I'd be game to
> paddling about some ideas and see if I can provide any insight. I think
> your system is sufficiently complex that you're not likely to get a
> tonne of response from the list.
>
> I think the most confusing part of your plea is all the Cisco-specific
> stuff at the end. It's still not totally clear what you're trying
to do.
> Can you try reframing it?
>
> -Stephen-
>