Re: Label type to be used

[Ashok Narayanan <ashokn@cisco.com>]

On Tue, Mar 23, 2004 at 02:20:55PM -0600, Ben Mack-Crane wrote:
> Hi Kireeti,
> 
> See in-line.
> 
> Regards,
> Ben
> 
> Kireeti Kompella wrote:
> 
> >Hi Ben,
> >
> >On Tue, 23 Mar 2004, Ben Mack-Crane wrote:
> >
> > 
> >
> >>The original text seems to have a sensible pattern.
> >>The proposed changed text does not.
> >>   
> >>
> >
> >Your responses below don't bear out your comment above: your
> >implementation uses port labels for [PSC, TDM/transparent], but the
> >original text says to use SUKLM.
> >
> >The sensibility of the pattern is also questionable; an equally
> >sensible pattern is to use port labels for [x, TDM/transparent].
> >
> If an interface supports transparent switching, it would fit the
> type [x, FSC], and thus use a port label for transparent LSP requests.
> So both [x, TDM] and [x, FSC] would fit the advertisement provided by
> a TDM port that supports both TDM channelized switching and transparent
> switching.  One would use SUKLM label in the first case and a port label
> in the second (as indicated in the GMPLS-SONET-SDH draft, and in the
> current text in the routing draft).

My understanding of how transparent switching works on a TDM switch is
not where it really should be to jump into this discussion, but what
the heck....

If you request a fully transparent TDM signal, that still implies that
it is a TDM signal, right? Could you connect a GigE port to a TDM
switch and request a OC-48 worth of fully transparent signal to
another GigE port on the other side? I believe the answer is no; and
in that case the switch can't truly advertise this link as FSC.

-Ashok

> 
> At least this is the way I understand the current docs.
> 
> >
> > 
> >
> >>In reviewing the discussion so far, it seems to me the best solution
> >>is to leave the text as is, understanding that switches capable of
> >>handling both TDM channelized switching as well as fully transparent
> >>(port or lambda) switching advertise multiple switching types.
> >>   
> >>
> >
> >I'm not sure how you reached the conclusion that the best solution is
> >to leave the text as is.  So far, there's been uniform agreement to
> >change the text, with Ashok counted as an abstention ("I won't really
> >object").
> >
> >The main point, though, is to come to a meaningful position that also
> >jives with current implementations -- ultimately, standards are to
> >enable interoperable implementations.
> >
> I thought my interpretation did match current implementations (as far
> as I can tell from the discussion to date).
> 
> 
> >
> ><snipped>
> >
> > 
> >
> >>>Please respond by Friday 3/26, 5pm PST with comments on:
> >>>
> >>>a) do you agree with the above change?
> >>>
> >>>     
> >>>
> >>No.
> >>
> >>   
> >>
> >>>b) in your implementation today, what do expect the label to represent
> >>> i) in the case of [PSC, LSC]?
> >>>
> >>>     
> >>>
> >>Lambda.
> >>
> >>   
> >>
> >>> ii) in the case of [PSC, TDM] with a fully transparent signal?
> >>>
> >>>     
> >>>
> >>Port.
> >>
> >>   
> >>
> >>>c) if you implement as the draft says, would it be a hardship to change
> >>> this?
> >>>
> >>>     
> >>>
> >>Yes.
> >>   
> >>
> >
> >Noted.
> >
> >Kireeti.
> >-------
> >
> > 
> >
> 
> 
> 
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-- 



--- Asok the Intern ----------------------------------------
Ashok Narayanan
IOS Network Protocols, Cisco Systems
1414 Mass Ave, Boxborough MA 01719
Ph: 978-936-1608.  Fax: 978-936-2218 (Attn: Ashok Narayanan)