Subject: physical vs. ephemeral terminations

From: Troy Cauble <[email-masked]>
Date: Tue, 30 Jan 2001 17:30:40 -0500

Hi all,

It seems that the protocol goes out of it's way to not
distinguish between physical an ephemeral terminations.

What is the error returned if an MG is asked to do something
it doesn't support (or doesn't even make sense) on that type
of termination?
        If it's asked to detect hook flash on an ephemeral
        termination?
        If it's asked to apply Local or Remote Descriptors
        to a physical termination?

This seems to indicate a whole class of syntactically correct,
but nonsensical combinations.

I'm pretty sure that SDP Local and Remote descriptors are
intended strictly for ephemeral terminations.  But I'm less
sure about Annex C Local and Remote descriptor content.  Opinions?

Also, it seems that given a termination id of CHOOSE, an MG must
traverse descriptors looking for clues that indicate whether it
should CHOOSE an ephemeral or physical termination.  Correct?
What if there is no forcing hint?

        A termination id schema must clearly distinguish between
        physical and ephemeral so the MGC knows how to pick a
        termination associated with some physical attribute
        (such as "POTS line 7"), yes?
        So the MG must pick between physical and ephemeral given
        a CHOOSE.

        A residential gateway might assume that CHOOSE implies
        ephemeral, since random physical choices have little use.
        A trunking gateway might be different though.

How useful is termination id ALL, if many operations don't make
sense on both classes of terminations?

-troy

---

From: Madhu Babu Brahmanapally <[email-masked]>
Date: Tue, 30 Jan 2001 18:47:22 -0500

hi Troy,
This is an age old issue. my comments below with[Madhu]

-----Original Message-----
From: Media Gateway Control (megaco)
[mailto:[email-masked]]On Behalf Of Troy Cauble
Sent: Tuesday, January 30, 2001 5:31 PM
To: [email-masked]
Subject: physical vs. ephemeral terminations

Hi all,

[Madhu] This is true and an intended outcome. The Megaco commands/messages
doesn't make any distinction between the type of terminations.

[Madhu]Agreed, But you can use the Local descriptor for physical termination
also. As shown in the same call scenario in the protocol.

[Madhu] Same as above.

[Madhu]According to my understanding CHOOSE is valid only for ADD command.
Its is an error for Modify,Subtract,Move,Audit commands and ServiceChange.
In Add command it indicates that the termination doesnot exist and MG has to
create one and respond with the newly created termination. I think that
CHOOSING is done only for ephemeral terminations.

        A residential gateway might assume that CHOOSE implies
        ephemeral, since random physical choices have little use.
        A trunking gateway might be different though.
[Madhu]Protocol message interpretation shouldn't differ on the type of
gateway implemented. Protocol defines messages applicable for all type of
gateway (Residential or Trunking).

How useful is termination id ALL, if many operations don't make
sense on both classes of terminations?
[Madhu]Whereever applicable it can be used.

-troy

---

From: Troy Cauble <[email-masked]>
Date: Tue, 30 Jan 2001 19:32:11 -0500

> sure about Annex C Local and Remote descriptor content.  Opinions?

Madhu,

Can you expand on this?  I did see that message 3 of Appendix A
used a Local descriptor with termination A4444, which based on
subsequent usage seems to be physical.  But I didn't understand it.
(Actually, I thought it was a mistake.)

Can you explain how setting Local descriptor properties on
a physical termination can make any sense?

> CHOOSING is done only for ephemeral terminations.

If this is true, I'd like to see it pointed out in the document.

Thanks,
-troy

---

From: Christian Groves <[email-masked]>
Date: Wed, 31 Jan 2001 13:28:35 +1100

G'Day Troy,

Please see my answers below marked [CHG].

Cheers, Christian

> > also. As shown in the same call scenario in the protocol.

[CHG] I don't see the problem of Local and Remote for Physical. L/R are
valid for both Physical and Euphemeral. For instance codec is valid in
L/R for euphemeral or physical.

> > sure about Annex C Local and Remote descriptor content.  Opinions?
[CHG] I don't understand the reasoning that they are strictly for
ephemeral terminations?

> If this is true, I'd like to see it pointed out in the document.

[CHG] No it is not true. Choosing can be done for a physical.

---

From: Madhu Babu Brahmanapally <[email-masked]>
Date: Wed, 31 Jan 2001 09:26:02 -0500

hi Christian,

But can the MG decide the type of termination to be Added(if CHOOSE
TerminationId is used in ADD)without looking at the descriptor information?
Because descriptors are parameters to a command that need to be applied on
the termination, but no means of identifying the termination type.

Best Regards.
Madhubabu

-----Original Message-----
From: Media Gateway Control (megaco)
[mailto:[email-masked]]On Behalf Of Christian
Groves
Sent: Tuesday, January 30, 2001 9:29 PM
To: [email-masked]
Subject: Re: physical vs. ephemeral terminations

G'Day Troy,

Cheers, Christian

---

From: Christian Groves <[email-masked]>
Date: Thu, 1 Feb 2001 10:06:13 +1100

Hello Madhu,

I believe a smart MG would look at the parameters.

Cheers, Christian