Subject: Re: Washington Issue 21 - Version Incompatibilities

From: Tom-PT Taylor <[email-masked]>
Date: Tue, 23 Nov 1999 13:43:46 -0600

Actually we realized in this morning's discussion that our rules
currently prevent any backward compatibility.  Basically the MG and MGC
have to negotiate a common version from the outset.  If they don't ,
then the end with the lower version has no way to distinguish a
syntactic error from either a proprietary or an official extension to
the protocol -- they all result in errors and failed transactions.

        -----Original Message-----
From:   Matt Holdrege [SMTP:[email-masked]]
Sent:   Tuesday, November 23, 1999 2:39 PM
To:     Taylor, Tom-PT [CAR:B904-I:EXCH]
Cc:     [email-masked]
Subject:        Re: Washington Issue 21 - Version Incompatibilities

        As was mentioned in our meeting in D.C., the ITU has no such
compunction
when it makes sense to deprecate certain aspects of a protocol in a new
version. Also, the IETF and pretty much everyone certainly *likes* to
keep
backwards compatibility if possible. Many IETF protocols have such a
requirement. Both organizations will do whatever makes sense.

        In general, saying that the ITU likes something is a pretty
dangerous
statement. The ITU, like the IETF, is pretty diverse.

        At 02:04 PM 11/22/99 -0500, Tom-PT Taylor wrote:

        >The ITU likes to keep major versions backward compatible.  The
IETF has no
>such compunctions.  I suppose operationally this means that Megaco
>versions will always be backwards compatible, meaning that we have no
use
>for minor versions.  Comments from the list?
>-----Original Message-----  From:   Christian Groves
>[SMTP:[email-masked]]  Sent:   Monday, November 22, 1999

>10:52 AM  To:     Taylor, Tom-PT
>[CAR:B904-I:EXCH]  Cc:     [email-masked]
Subject:
 >     Re: Washington Issue 21 - Version Incompatibilities
>
>G'Day all,
>
>I believe this should be in the base H.248 protocol specification.
>
>I agree with Tom that the major and minor numbering needs to
>be  considered? Tom what would cause a minor re-numbering compared to
>a  major renumbering considered that we need to keep each version
(minor
>or  major) backwards compatible.
>
>Cheers, Christian

---

From: Matt Holdrege <[email-masked]>
Date: Fri, 3 Dec 1999 10:40:27 -0800

We are backwards compatible. We have negotiation. If negotiation fails,
then there is no association. But if an MGC has both version 1 and 2, it
can communicate with MG's that use either version thanks to negotiation.

At 01:43 PM 11/23/99 -0600, Tom-PT Taylor wrote:

>Actually we realized in this morning's discussion that our rules currently
>prevent any backward compatibility.  Basically the MG and MGC have to
>negotiate a common version from the outset.  If they don't , then the end
>with the lower version has no way to distinguish a syntactic error from
>either a proprietary or an official extension to the protocol -- they all
>result in errors and failed transactions.
>-----Original Message-----  From:   Matt Holdrege
>[SMTP:[email-masked]]  Sent:   Tuesday, November 23, 1999 2:39
>PM  To:     Taylor, Tom-PT
>[CAR:B904-I:EXCH]  Cc:     [email-masked]  Subject:
>compunction  when it makes sense to deprecate certain aspects of a
>protocol in a new version. Also, the IETF and pretty much everyone
>certainly *likes* to keep backwards compatibility if possible. Many IETF
>protocols have such a requirement. Both organizations will do whatever
>makes sense.
>
>dangerous  statement. The ITU, like the IETF, is pretty diverse.
>
> >The ITU likes to keep major versions backward compatible.  The IETF has
> no  >such compunctions.  I suppose operationally this means that
> Megaco >versions will always be backwards compatible, meaning that we
> have no use >for minor versions.  Comments from the list?  >-----Original
> Message-----  From:   Christian
> Groves  >[SMTP:[email-masked]]  Sent:   Monday, November
> 22, 1999 >10:52 AM  To:     Taylor,
> Tom-PT >[CAR:B904-I:EXCH]  Cc:     [email-masked]
> Subject:  >     Re: Washington Issue 21 - Version
> Incompatibilities  >  >G'Day all,  >  >I believe this should be in the
> base H.248 protocol specification.  >  >I agree with Tom that the major
> and minor numbering needs to  >be  considered? Tom what would cause a
> minor re-numbering compared to >a  major renumbering considered that we
> need to keep each version (minor >or  major) backwards
> compatible.  >  >Cheers, Christian