Friday, May 23, 2008

Re: [asterisk-biz] SIP , SIP-I and SIP-T

Trixter aka Bret McDanel wrote:
> On Fri, 2008-05-23 at 06:36 -0400, Alex Balashov wrote:
>> Dome Charoenyost wrote:
>>
>>> Can someone explain about SIP,SIP-T and SIP-T ?
>>> and Asterisk support SIP-I,SIP-T or not ?
>> It is a way to map and/or encapsulate some values particular to PSTN
>> signaling protocols (such as ISUP) back into SIP so that SIP can serve
>> as a minimally viable transport between two nodes that speak those
>> protocols, i.e.
>>
>> ISUP ----> SIP/ISUP gateway ----> IP ----> SIP/ISUP gateway ---> ISUP
>>
>> Asterisk does not really support these because it is a back-to-back user
>> agent, so it does not need to follow RFC rules regarding conservation of
>> special headers or data elements in a transaction the way that a proxy
>> does. Asterisk can and will regenerate new call legs scoped to the
>> interface technologies it actually supports and cares about.
>>
>
> Supporting them has nothing to do with being a B2BUA, PBX or softswitch.
> They are variants of SIP, and as such they would require a proper
> protocol stack to support. More at the end on this.

I think I misspoke. What I meant was that because Asterisk does not
have a protocol stack for these, it will not "support" them in the sense
that it will neither (1) take advantage of their features or provide any
features specific to those implementations, or (2) pass / tunnel those
protocols passively. In the latter case, being a B2BUA does have a lot
to do with that.

--
Alex Balashov
Evariste Systems
Web : http://www.evaristesys.com/
Tel : (+1) (678) 954-0670
Direct : (+1) (678) 954-0671
Mobile : (+1) (706) 338-8599

_______________________________________________
--Bandwidth and Colocation Provided by http://www.api-digital.com--

asterisk-biz mailing list
To UNSUBSCRIBE or update options visit:

http://lists.digium.com/mailman/listinfo/asterisk-biz

No comments: