Extra Time For Megaco

Tom-PT Taylor taylor at NORTELNETWORKS.COM
Wed Jun 30 08:57:17 EDT 1999


Tom,

Thanks for the nice summary of events regarding gateway decomposition. I just
want to comment on a few minor things (see below.)

--Hong

Tom-PT Taylor wrote:

> Here's a brief history, from my point of view -- others are free to add
> their viewpoints.
>
> April 1998: Bellcore announces SGCP (Simple Gateway Control Protocol).  They
> have been prototyping for several months.  Hong Liu was one of the
> participants.  I have the impression that many of the ideas came from
> Christian Huitema, including the use of SDP, the separation into local and
> remote descriptors which are effectively negotiated between MGs, and the use
> of application-level framing instead of a reliable transport layer.  SGCP
> meets with a hostile reception in SG 16 and TIPHON because of its
> centralizing architecture, which differs subtly from that of H.323.
>
> May 1998: A cluster of activity around the issue of control of VoIP gateways
> where SS7 is terminated on separate signalling gateways (to conserve point
> codes).  Nortel is proposing the use of an extension of DIAMETER, a protocol
> under development at the IETF, to do device control.  Ascend and Bay have
> extensions to Q.931 for the purpose, which they eventually rationalize into
> a single protocol proposal.
>
> May 1998: Level 3 announces the formation of a multi-company Technical
> Advisory Committee to work on an IP Device Control protocol (IPDC).  The TAC
> is presented with a 100-page specification previously developed by Ascend
> and XCOM as their starting point.  Other companies have in-house protocols,
> and SGCP is also considered, but the TAC ends up using a modified IPDC over
> a DIAMETER base.  IPDC includes the important concepts of event packages and
> scripts.
>
> June 1998: The TAC presents their list of requirements to the H.323
> Rapporteurs' meeting in Cannes.  Intel presents an abstract proposal for
> H.323 gateway decomposition.  Bellcore presents SGCP.  Work on gateway
> decomposition does get started, despite initial hostility and suspicion.  A
> TIPHON meeting around this time at least became familiar with the topic.

I recalled that SGCP was discussed in Cannes. But SGCP as a protocol was not
submitted to ITU-T SG 16 as a contribution. In fact, only MGCP was submitted to
ITU-T SG 16, and the first submission was in 11/98 at the Torino's meeting.

>
>
> August 1998: the Level 3 TAC concludes its work and presents a first draft
> of IPDC to the IETF and SG 16.  All the discussion of SS7 gateways and
> remote control of VoIP gateways culminates in a Birds of Feather (BOF)
> session at the IETF.  Out of that eventually comes the decision to form two
> working groups: SIGTRAN (transport of SCN signalling over IP) and MEGACO
> (Media Gateway Control).  That decision doesn't come until December, but in
> the meantime there is active discussion of issues on the IETF lists.  TIPHON
> adds gateway decomposition to its architecture, but is having trouble
> getting a firm view of that architecture.
>
> September 1998: SG 16 considers gateway decomposition and commits itself to
> working on the topic.  Terms of reference are drawn up, along with a
> reworking of architectural views initially drawn up in June.  Bellcore  and
> Level 3 announce a merger of SGCP and IPDC into MGCP.  The latter is mostly
> SGCP with the addition of event packages and termination wildcarding syntax.
>

The actual merger of SGCP and IPDC occurred around 10/98. MGCP was announced at
the end of 10/98.

>
> November 1998: TIPHON architectural views are settling down.  Lucent brings
> in MDCP (Media Device Control Protocol) as a hand-written draft to the SG 16
> Rapporteurs' meeting in Torino.  This is completely different from MGCP,
> particularly in its connection model.
>
> December 1998: first meeting of the Megaco working group at the IETF.  A
> first draft of a requirements document comes out shortly thereafter.
>
> March 1998: a bitter debate over connection model at the Monterey
> Rapporteurs' meeting.  In a procedure unusual for SG 16, the MDCP connection
> model is chosen via an indicative poll.
>

That was Feb 1999. I would not forget this, -:)

>
> April 1998: compromise reached at last on the connection model, at the IETF.
> The new model accommodates all of the additional requirements which have
> arisen beyond the original design premises of SGCP, and improves on both the
> SGCP/MGCP and MDCP models.
>

That was March 1999 IETF meeting in Minneapolis when the compromised model was
reached by a design team. The actual I-D came out in April 1999.

>
> May 1998: formal Megaco/H.GCP cooperative arrangement announced.
>

Again, it was May 1999 ITU-T SG 16 meeting in Santiago, Chile. And the
IETF/ITU-T arrangement was announced (prematurely) in a very strange way, and
the announcement was to the surprise of most people in the meeting.

>
> > -----Original Message-----
> > From: Derks, Frank [SMTP:F.Derks at PBC.BE.PHILIPS.COM]
> > Sent: Wednesday, June 30, 1999 6:24 AM
> > To:   ITU-SG16 at MAILBAG.INTEL.COM
> > Subject:      Re: MGCP reference (was Re: Megaco/H.gcp conference call)
> >
> > HI Nancy,
> >
> > maybe it is a good idea to post the history of all these protocols and
> > their
> > relations (if any) to this list?
> >
> > Frank
> >
> > -----Original Message-----
> > From: Nancy-M Greene [mailto:ngreene at NORTELNETWORKS.COM]
> > Sent: 29 June 1999 21:34
> > To: ITU-SG16 at MAILBAG.INTEL.COM
> > Subject: Re: MGCP reference (was Re: Megaco/H.gcp conference call)
> >
> >
> > Chip, you are right, the name Telcordia/Level 3/RSL COM/Vertical MGCP is
> > not
> > convenient. Christian has already made the same comment you have. I said
> > in
> > reply to him, and to the list, that I did make an error in adding Cisco to
> > the qualifier for MGCP. Since then, I refer to the new Megaco protocol as
> > the Megaco protocol, or the Megaco/H.gcp protocol, and to MGCP as MGCP.
> >
> > Since a new version of MGCP has come out, version 1,
> > (draft-huitema-megaco-mgcp-v1-00.txt), this distinction is even more
> > necessary. It makes sense that megaco is part of the file name, because
> > there are parts of MGCP that still need to be turned into RFCs for
> > packages
> > for the Megaco/H.gcp protocol, but it means the new Megaco/H.gcp protocol
> > can never really be called MGCP - it is too confusing. It would be good at
> > some point to pull the packages out of MGCP to stand alone as a separate
> > document for Megaco. And perhaps the UDP + timers part of MGCP so that it
> > can stand beside TUDP, MDTP, and TCP as alternatives for Megaco transport.
> >
> > Nancy
> > --------------------------------------------------------------------------
> > Nancy M. Greene
> > Internet & Service Provider Networks, Nortel Networks
> > T:514-271-7221 (internal:ESN853-1077) E:ngreene at nortelnetworks.com
> >
> > > ----------
> > > From:         Chip Sharp[SMTP:chsharp at cisco.com]
> > > Sent:         Tuesday, June 29, 1999 2:53 PM
> > > To:   Greene, Nancy-M [CAR:5N10:EXCH]; ITU-SG16 at mailbag.cps.intel.com;
> > > megaco at standards.nortelnetworks.com
> > > Subject:      MGCP reference (was Re: Megaco/H.gcp conference call)
> > >
> > > Once or twice is a mistake.  When the mistake is continually repeated I
> > > wonder...
> > >
> > > Cisco is NOT an author of MGCP.  Referring to MGCP as
> > > "Telcordia/Cisco MGCP" denigrates the hard work of the many people that
> > > actually did author the draft as well as the many people and companies
> > > that
> > > contributed.
> > > Maybe it isn't convenient to call it Telcordia/Level 3/RSL COM/Vertical/
> > > MGCP?
> > >
> > > Chip
> > >
> > > At 06:44 PM 6/16/99 -0400, Nancy-M Greene wrote:
> > > ...snip...
> > > >mechanism. We need to choose one. There are two proposals on the table:
> > > >1) the UDP + timers method in the Telcordia/Cisco MGCP  -
> > > >draft-huitema-megaco-mgcp-v0r1-05.txt, and
> > > ...snip...
> > > --------------------------------------------------
> > > Chip Sharp                 voice: +1 (919) 851-2085
> > > Cisco Systems              Consulting Eng. - Telco
> > > Reality - Love it or Leave it.
> > > --------------------------------------------------
> > >



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