Re: RE : RE : TR : I-D ACTION:draft-leroux-ccamp-gmpls-mrn-eval-00.txt

["Adrian Farrel" <adrian@olddog.co.uk>]

Why are we talking about signaling virtual FA LSPs?
I thought the point of a virtual FA was that it was entirely putative.

Seems like you are talking about something more solid than a virtual FA
LSP.

Adrian

----- Original Message ----- 
From: "dimitri papadimitriou" <dpapadimitriou@psg.com>
To: "Igor Bryskin" <i_bryskin@yahoo.com>
Cc: <Dimitri.Papadimitriou@alcatel.be>; "Igor Bryskin"
<ibryskin@movaz.com>; "LE ROUX Jean-Louis RD-CORE-LAN"
<jeanlouis.leroux@francetelecom.com>; <ccamp@ops.ietf.org>
Sent: Saturday, March 05, 2005 3:03 PM
Subject: Re: RE : RE : TR : I-D
ACTION:draft-leroux-ccamp-gmpls-mrn-eval-00.txt


> igor - i will provide a detailed answer concerning a clean method to
> deal with "virtual FAs" that does not rely on the use of the protection
> object (and therefore would deliver a clean method to provide signaling
> for protected "virtual FAs"
>
> hopefully we can discuss this during this IETF meeting,
>
> thanks,
> - dimitri.
>
> Igor Bryskin wrote:
>
> > Dimitri,
> >
> > See at the bottom
> >
> >
> >>>IB>>Well, are they? They give you a way to signal a
> >>>requirement not to commit resources for an LSP
> >
> > until
> >
> >>>further notice and also to require their commitment
> >>>when it becomes necessary. Why not to allow working
> >>>LSP to be signaled as Secondary according to the
> >>>mentioned draft? Then it would be possible even to
> >>>signal protected virtual FAs, which is not as
> >
> > stupid
> >
> >>>as it may sound :=)
> >>
> >>Sorry but this sounds really bad...
> >>Please let me know then how do you signal protected
> >
> > virtual FAs?
> >
> >>IB>> You signal both working and protection LSPs of
> >
> > the FA as Secondary.
> > At
> >
> >>the time when you decide to make FA "real" you
> >
> > re-signal working or both
> >
> >>LSPs (depending on protection type) as Primary.
> >
> > Don't see why this
> > wouldn't
> >
> >>work.
> >>
> >>DP> because what do you do in case the primary
> >
> > (virtual) FA-LSP fails ?
> > you
> >
> >>are simply going to activate the secondary (virtual)
> >
> > FA-LSP which is in
> >
> >>clear
> >>opposition with the notion of virtual-FA - the
> >
> > reason is again because you
> >
> >>are trying to use one bit i.e. S to say something in
> >
> > a context (protection
> >
> >>object) for which it has not been designed for
> >>
> >
> >
> > IB>> Oh-Oh, what do you mean by "primary (virtual)
> > FA-LSP fails" and  "you
> > are simply going to activate the secondary (virtual)
> > FA-LSP "?  I activate
> > protection LSP if I have a failure in the *data plane*
> > of the working LSP.
> > But working LSP of the virtual FA does not have any
> > data plane yet, there is
> > nothing that can trigger the protection LSP activation
> > and switchover.
> >
> > DP> but they are associated to resources they do not
> > use - and the control plane role is to ensure that
> > when they need to be activated resources can be used -
> > the question JL raises is the problem of "how do i
> > protect a virtual FA" and the response is if you are
> > using the S bit for telling i am a virtual FA you can
> > not use it anymore to ensure protection of a primary
> > (and even less a secondary !) - this said an secondary
> > LSP exists only within the context of its primary
> >
> > IB>>Here is what I have in mind.
> >
> > A network operator configures a mesh of virtual FAs.
> > Working FA LSPs are signaled as Secondary. Once they
> > are established the FA TE link ends are advertised.
> > Resources for these LSPs are allocated on the links
> > the LSPs are going through, however, they are not
> > committed (not bound into cross-connects). Two or more
> > virtual FA LSPs may share the resources on common
> > links. This is especially true for those of them that
> > are unlikely to become real at the same time.
> > Furthermore, polices could be such that virtual FA LSP
> > resources could be allowed to get pre-empted by real
> > (not necessarily FA-) LSPs. The mentioned resources
> > also could be involved in mesh restoration schemes and
> > even be bound into extra traffic LSPs.
> >
> > When a virtual FA transforms into real FA, its working
> > FA-LSP is re-signaled as Primary. At this time, the
> > allocated resources are bound into FA-LSP
> > cross-connects. Naturally, all other LSPs – virtual or
> > real – that share resources with the FA-LSP in
> > question are notified and need to be recomputed and/or
> > re-signaled.
> >
> > A virtual FA could be provisioned as protected in a
> > sense that when it becomes real it will have a certain
> > protection scheme already in place. Path computation
> > for backup LSPs of virtual FAs is performed just like
> > of real FAs, that is, by assuming that associated
> > working LSPs are Primary (fully built) LSPs.
> > Regardless of the protection type backup LSPs of
> > virtual FAs are always signaled as Secondary. At the
> > time when a virtual FA is transformed into real one
> > (that is, when its working LSP becomes Primary) its
> > backup LSP(s) may be activated as well (e.g. 1+1
> > protection) or may be left Secondary until the working
> > LSP data plane failure is detected (e.g. shared
> > protection).
> >
> > Igor
> >
> >
> >
> >
> >
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