[cisco-voip] QSIG over H323 with GK

[James Brown]

OK, so essentially by speaking different dialects of QSIG, it's the 
supplementary services which might break. We could probably live with 
that between the IP Phones and the TDM environment. Does anyone know 
whether ISO QSIG support is on the roadmap for IOS?

Also, how would an IOS Gateway react to receiving Annex M tunnelled QSIG 
from UCM one minute and GTD tunnelled QSIG from another IOS GW the next? 
I haven't seen any documentation from Cisco to suggest they support 
this, but given that you can't change the behaviour on either device, 
I'd have to assume there's no problem. Any thoughts?

Regards

James.

Nick Matthews wrote:
> All of QSIG is really just supplementary features.  The only
> difference between normal ISDN PRI and ISDN QSIG is the availibility
> of certain supplementary features like call-back, MWI, forwards, CLI
> delivery, etc.
> 
> 
> 
> -nick
> 
> On Fri, Apr 24, 2009 at 3:11 AM, James Brown
> <james.m.h.brown at googlemail.com> wrote:
>> Thank you Nick. I'm not sure about changing the service parameter to ECMA
>> because we'd like to use Inter Cluster Trunking at some point. According the
>> the System Guide, UCM 6.1 "does not support ECMA with QSIG tunneling over
>> intercluster trunks". Since this is a global parameter, I guess we'd have to
>> leave it on ISO. Would this prevent basic calls connecting, or does it just
>> affect the supplementary features, like CLI?
>>
>> Regards
>>
>> James.
>>
>> Nick Matthews wrote:
>>> A few notes:
>>>
>>> -CUCM has an advanced service parameter to switch between ISO/EMCA.
>>> It would be for every QSIG link.
>>> -GK should only be relevant to routing calls, which for QSIG purposes
>>> should be basic H323.
>>>
>>> H323 is the best choice for this since it's based off of Q.931 and
>>> you'll see less 'conversion' of parameters.
>>>
>>>
>>>
>>> -nick
>>>
>>> On Thu, Apr 23, 2009 at 6:54 PM, James Brown
>>> <james.m.h.brown at googlemail.com> wrote:
>>>> All,
>>>>
>>>> We have an opportunity to convert some existing QSIG E1 tie-lines
>>>> (between
>>>> TDM PBXs) to IP and at the same time allow our UCM cluster to reach the
>>>> PBX
>>>> sites. I wondered if anyone could spare a few minutes to advise me on the
>>>> implementation please?
>>>>
>>>> My preferred setup would be:
>>>>
>>>> UCM H225 Trunk <--> GK <--> H323 IOS GW <--> TDM PBX
>>>>
>>>> The reason I like H323 in this instance is that this environment includes
>>>> four separate PBXs and I'd like to keep the old dial-plan away from UCM
>>>> and
>>>> use GK CAC. The PBXs are various Nortel models and I believe the IOS H323
>>>> implementation may offer slightly more flexibility when integrating.
>>>>
>>>> Having read around the topic, it seems that UCM supports ISO QSIG whereas
>>>> IOS supports ECMA QSIG. To make matters worse, UCM tunnels QSIG over H323
>>>> using Annex M, while IOS uses the GTD field within a GKTMP message.
>>>>
>>>> Could anyone tell me whether a Cisco GK could successfully reconcile what
>>>> looks like a different versions of QSIG and different tunnelling
>>>> mechanisms
>>>> please? Is the approach I'm taking valid, or would I be better using
>>>> MGCP?
>>>> Does anyone have any experiences they could share when integrating with a
>>>> Nortel Option 61/81 with QSIG?
>>>>
>>>> Many thanks,
>>>>
>>>> James.
>>>>
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>>>>
>>