Protocol version re-negotiation

Michael Brown C.Michael.Brown at NORTELNETWORKS.COM
Wed Feb 28 16:43:34 EST 2001


Nancy,

   The parameter that would be used is be the ServiceChangeAddress. As far
as the assumption that the MGC would be provisioned with the primary and
secondary MGs, certainly it could be done that way (and the text in 11.4
does imply this), but I do think that passing the address is an acceptable
approach and should certainly be allowed.

   IMO we don't really need a new method for this. I don't see how adding a
new method is more efficient. I still would contend that adding a
ServiceChangeReason is sufficient and that it is desirable to do so (at
least in V.2).

Michael

-----Original Message-----
From: Nancy Devin [mailto:nancy.devin at alcatel.com]
Sent: Tuesday, February 27, 2001 1:07 PM
To: Brown, Michael [NC1:GW10:EXCH]
Cc: ITU-SG16 Mail List; megaco at fore.com
Subject: Re: Protocol version re-negotiation



Hi Mike,

I don't understand why your are talking about passing the address of the
secondary
MG to the MGC during a Failover.  My understanding is that the MGC is
configured
with both the primary MG address and the secondary MG address (even though I
did
not find any text on that).  If that is not the case then which parameter is
used
to transmit the address the the MGC.

Also, I think the idea of having to Handoff to another MG or Failover to the
other
MG may not be the most efficient one.  If we are to add a new reason then
why not
also add a new method which would be "VersionNegotiation"

Method:               VersionNegotiation
TerminationID:    Root
Reason:                MG directed change / MGC directed change
Description:
Sent from the MG to the MGC, the MG initiates a protocol version
negotiation.  Sent
from the MGC to the MG, the MGC initiates a protocol version negotiation.


Nancy


Michael Brown wrote:

> Comments inline.
>
> Michael
>
> "Rosen, Brian" wrote:
>
> >
> > > I think you missed one point: "How does a NON-redundant MG
> > > upgrade to a
> > > new version of the protocol?"
> > It comes down, reboots, and comes up again - it's a service affecting
> > change.  AFAIK, that's the only way today.
>
> <MB> Yes, if the MG is really Non-redundant there doesn't seem to be an
option.
>
> >
> > >
> > > Can the MG Failover to itself? Will this cause any problems
> > > in the MGC?
> > Since that's not a defined option, some MGCs might have a problem.
>
> <MB> While there is no existing text specifically saying that this is
allowed.,
> there also is none that disallows this behavior. It seems to me that the
MGC
> should just accept the "new" address for the "secondary" MG and go on.
This
> would be used when an MG and its mate hide behind a single address for the
MGC
> <> MG control association. I would think that this could easily be added
to the
> implementor's guide and I don't think that it should cause problems.
>
> >
> >
> > >
> > > To allow this requires only a few changes to the text in RFC3015 as
> > > follows:
> > > Section 7.2.8 ServiceChange
> > > Modify text: "6) Failover - sent from MG to MGC to indicate
> > > the primary
> > > MG is out of service and a secondary is taking over, or to indicate a
> > > version negotiation from the MG."
> > > Add a Reason: "Version Negotiation" or a more generic "MG Directed
> > > Change".
> > > Add text: "The MG may initiate a version negotiation with a
> > > ServiceChange Command specifying the "Root" for the TerminationID,
> > > ServiceChangeMethod equal to Failover and ServiceChangeReason equal to
> > > "Version Negotiation"."
> > I think that's a scope add, which I for one am reluctant to do.
> > If there was a real problem with something we already had, that's one
thing,
> > but a real feature add, I'm less thrilled about.  I'll admit some of the
> > things
> > we have talked about stray at least close, if not over such a line.
Here,
> > I think an MG that can do a non-service affecting upgrade which is not
> > redundant is pretty unusual these days - I don't mean to discourage
folks
> > from doing that, but I also don't feel we need changes in semantics (and
> > some additional syntax, albeit some IANA registrations) to make it
happen,
> > it can wait for V2.
>
> <MB> I'm suppose I'd agree that this propoal is adding a new feature as it
would
> require a new, IANA registered reason and the associated behavior. I'd say
it's
> somewhat unfortunate because basically, I don't see problems with the
proposed
> approach. There is one thing about the approach that bothers me which we
might
> consider for V2. That is, the use of Failover in this instance seems
> inappropriate. The name just seems to imply that a software upgrade is a
failure
> scenario. I would suggest that it would be nicer  to enhance the
definition of
> Handoff rather than Failover since handoff implies a more graceful
transition.
> Given the current definitions of Handoff and Failover in version 1, we do
have
> to live with Failover for now.
>
> >
> >
> > >
> > > Cheers,
> > > Paul
> > >
> > > "Rosen, Brian" wrote:
> > > >
> > > > It's unlikely that we will do anything that adds
> > > > new features by edits to the implementor's guide.
> > > > It's reasonable to have explanatory text in such a
> > > > document that is not normative.
> > > >
> > > > I think you failover, upgrade, and failover back
> > > > with this version of the protocol.
> > > >
> > > > Brian
> > > >
> > > > > -----Original Message-----
> > > > > From: Paul Rheaume [mailto:paul.rheaume at alcatel.com]
> > > > > Sent: Thursday, February 22, 2001 1:00 PM
> > > > > To: ITU-SG16 Mail List
> > > > > Cc: megaco at fore.com
> > > > > Subject: Re: Protocol version re-negotiation
> > > > >
> > > > >
> > > > > Folks,
> > > > >
> > > > > Where is the appropriate list to discuss this issue?
> > > > >
> > > > > We feel that version negotiation and the version upgrade
> > > > > process is not
> > > > > well specified and needs to be discussed and properly
> > > defined at the
> > > > > latest in version 2 of the specification. That means
> > > looking at this
> > > > > very soon.
> > > > >
> > > > > I think this issue belongs to the next version of the
> > > Implementor's
> > > > > Guide.
> > > > >
> > > > > Regards,
> > > > > Paul
> > > > >
> > > > > Nancy Devin wrote:
> > > > > >
> > > > > > How does a non-redundant MG upgrade to a new
> > > > > > Megaco version without affecting service?  How
> > > > > > does a redundant MG upgrade to a new Megaco
> > > > > > version without affecting service?
> > > > > >
> > > > > > It is mentionned in RFC3015 that Protocol version
> > > > > > negotiation can be done at Restart, Failover, and
> > > > > > Handoff serviceChanges.  It is not mentionned
> > > > > > explicitly how version protocol re-negotiation is
> > > > > > done after the MG has registered with the MGC. in
> > > > > > both situation
> > > > > >
> > > > > > This could be done in at least two different ways
> > > > > > as listed bellow.
> > > > > >
> > > > > > 1-    Protocol version negotiation could be
> > > > > > initiated using the Failover serviceChange.  A
> > > > > > Failover serviceChange with a protocol version
> > > > > > would indicate that the MG has been configured
> > > > > > with a new H.248 protocol version.  Sent from the
> > > > > > MG to the MGC, it indicates that the MG has been
> > > > > > configured with a new H.248 protocol version.
> > > > > > This serviceChange shall not indicate Failure of
> > > > > > the working MG.  This would require that for
> > > > > > non-redundant MGs, both the primary IP address and
> > > > > > the secondary IP address be the same.
> > > > > >
> > > > > > 2-    Protocol version negotiation could be
> > > > > > intiated using a new serviceChange method:
> > > > > > VersionNegotiation (Method 7 of the serviceChange
> > > > > > command as defined in RFC3015) This serviceChange
> > > > > > would be sent from the MG to the MGC to initiate
> > > > > > protocol version initiation.  It indicates that
> > > > > > the MG has been configured with a new H.248
> > > > > > protocol version.  Sent from the MGC to the MG, it
> > > > > > indicates that the MGC has been configured with a
> > > > > > new H.248 protocol version.
> > > > > >
> > > > > > Comments please.
> > > > > > Nancy
> > > > >
> > >

--
Nancy Devin
Software Designer

Alcatel
600 March Road, P.O. Box 13600
Kanata, Ontario, Canada
K2K 2E6

Telephone: (613) 591-3600 x6897
Fax:       (613) 599-3609
Internet:  nancy.devin at alcatel.com


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