Subject: Re: [Sipping] SUMMARY: Trunk groups in R-URI

From: [email-masked]
Date: Mon, 9 Sep 2002 09:41:43 EDT

In a message dated 9/5/02 3:56:31 PM Eastern Daylight Time, [email-masked] 
writes:

> In addition to that, an entity (like a proxy) may need to pass
> information downstream to a gateway (UAS).  Also, a gateway getting a
> call from the PSTN may choose to pass the originating trunk group to
> its default outbound proxy.  Admittedly, the former will be more
> prevelant.
> 
> Mike: with regard to your first sentence above, I am not sure if you are
> asking *why* do we need trunk groups at all, or why would one entity
> want to communicate this information to the other one? (I suspect you
> may know the answer to both...)
> 

Yes, I understand these cases, a directly associate proxy and gateway need to 
communicate the trunk group ID for in incoming or outgoing call. I was mostly 
questioning the example someone gave of Proxy A needing to pass an identifier 
to Proxy B for trunk groups behind a gateway that only Proxy B should knwow 
about.

Yes, of course I am not asking *why* we need trunk groups.

Mike Pierce
Artel

---

From: "Cullen Jennings" <[email-masked]>
Date: Mon, 9 Sep 2002 23:28:48 -0700

I was thinking of a case along the following lines - Proxy A and B are both
in the same administrative domain.

Imagine Proxy A is a very intelligent routing proxy that knows all about
least cost routing with time of day issues and so on. Proxy A decides the
call should go out a particular trunk group. Proxy A sends the call to a
proxy B that does not know much but talks TRIP to several GWs in a a single
POP and manages several GWs that interact with this trunk group. Proxy B
load balances between the GWs in the POP and also keeps track of any that
are down and does not send calls to them. Proxy A dealt with which trunk
group to terminate the call on - proxy B dealt with resource availability to
pick an appropriate GW. Proxy A needed to tell Proxy B which trunk group to
use. One might argue that Proxy A should have just picked the GW but there
might be scaling issues with Proxy A knowing all resource information.

Cullen

  -----Original Message-----
  From: [email-masked] [mailto:[email-masked]]On Behalf Of
[email-masked]
  Sent: Monday, September 09, 2002 6:42 AM
  To: [email-masked]
  Cc: [email-masked]; [email-masked]
  Subject: Re: [Sipping] SUMMARY: Trunk groups in R-URI

  Yes, I understand these cases, a directly associate proxy and gateway need
to communicate the trunk group ID for in incoming or outgoing call. I was
mostly questioning the example someone gave of Proxy A needing to pass an
identifier to Proxy B for trunk groups behind a gateway that only Proxy B
should knwow about.

  Mike Pierce
  Artel