Subject: Re: Washington Issue 21 - Version Incompatibilities

From: Matt Holdrege <[email-masked]>
Date: Tue, 23 Nov 1999 11:39:05 -0800

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: Tue, 23 Nov 1999 11:55:20 -0800

I have no problem with that. If the two endpoints can't speak the same
language they should terminate their association. As long as we have
negotiation we should be OK. Realistically, MGC's will probably be required
(by the market) to handle multiple versions as it will take longer for MG's
to be upgraded.

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
>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.
>
> >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