RE: Doubt in draft draft-ietf-mpls-generalized-signalling-05.txt

[Ayan Banerjee <abanerjee@calient.net>]

Manoj,

It is possible that a "port" on a multi-service platform may behave
dynamically in one of two (or more) different ways depending on the 
internal switching capabilities. For example, a port may be described 
to be PSC capable and TDM capable at the same time. This capability 
of the port is the "switching capability" of a port. The "switching 
capability" and the "encoding" are orthogonal fields. For example, 
it is possible to request for a TDM switching capability with 
specific encoding of SONET (or SDH). For a distant node to be aware 
of how the LSP is to be setup (that is for the transit node to set up 
its internal switching appropriately) and to allow for a particular 
valid encoding on the port for this requested switching capability, it 
is necessary to carry both fields (in the connection setup request). 

The MAX LSP bandwidth that is announced per switching capability lets 
a remote (source) node whether there is available bandwidth with respect 
to connection setup. It may be desired to restrict the switching capability 
of a port based on the connection setup priority. The announcements 
via routing of the LSP bandwidth across each priority for a given
switching capability serves this purpose. 

Thanks,
Ayan
  

-----Original Message-----
From: manoj juneja [mailto:manojkumarjuneja@hotmail.com]
Sent: Wednesday, August 01, 2001 10:43 AM
To: jdrake@calient.net; zwlin@lucent.com
Cc: ccamp@ops.ietf.org; lberger@movaz.com; Eric.Mannie@ebone.com;
kireeti@juniper.net
Subject: RE: Doubt in draft
draft-ietf-mpls-generalized-signalling-05.txt


Hi John,
         There are "switching Capability" and "encoding" fields inside 
"switching type" field. The switching capability includes the same set of 
values as LSP encoding type. Even encoding field also indicate LSP encoding 
type. What is the need for this duplication in Generalized Label Request 
Object? The max. LSP bandwidth for different priority levels (p= 0...7) is 
also specified and is only valid in case switching cap/LSP encoding type is 
TDM. If I am establishing just a normal SDH/SONET LSP then why do I need 
different priority levels ? I think it is only valid if I establish 
SDH/SONET LSP as a forwarding adjacency (FA). Furthermore, the max. LSP 
bandwidth at different priority levels should indicate differnet LOVCs viz. 
VT1.5...VT6 or VC-2...VC-11.

I think all the fields viz. LSP encoding type (in Generalized Label Req 
object), swiching capability (in switching type), Encoding (in switching 
type) indicate more or less the similar type of meaning.
I think the switching type field (in generalized label request object)
should be kept optional for LSP encoding type as PSC-[1-4], FSC and LSC.

Please correct me if I am wrong.

Regards,
manoj.


>From: John Drake <jdrake@calient.net>
>To: Zhi-Wei Lin <zwlin@lucent.com>, manoj juneja  
><manojkumarjuneja@hotmail.com>
>CC: ccamp@ops.ietf.org, lberger@movaz.com, Eric.Mannie@ebone.com, Kireeti 
>Kompella <kireeti@juniper.net>
>Subject: RE: Doubt in draft draft-ietf-mpls-generalized-signalling-05.txt
>Date: Wed, 1 Aug 2001 08:54:56 -0700
>
>Zhi,
>
>I thought that Vishal had answered this a while ago.  A TE Link can now 
>have
>multiple switching (nee multiplexing) capabilities.  Given this, it's
>necessary in signalling to identify which switching capability the LSP
>wishes to use.
>
>Thanks,
>
>John
>
>-----Original Message-----
>From: Zhi-Wei Lin [mailto:zwlin@lucent.com]
>Sent: Tuesday, July 31, 2001 10:14 PM
>To: manoj juneja
>Cc: ccamp@ops.ietf.org; lberger@movaz.com; Eric.Mannie@ebone.com;
>Kireeti Kompella
>Subject: Re: Doubt in draft
>draft-ietf-mpls-generalized-signalling-05.txt
>
>
>Hi,
>
>I have not heard any response to Manoj's question from the folks who
>added this field as to what use it is envisioned...
>
>Can someone enlighten me? Thanks!
>
>Zhi
>
>
>manoj juneja wrote:
> >
> > Hi All,
> >          I have following doubt in
> > "draft-ietf-mpls-generalized-signalling-05.txt" draft.
> > This draft has introduced new field switching type in Generalized
> > Label Request Object. After looking at the structure of switching type
> > field in latest OSPF document (GMPLS extensions to OSPF, Field Name :
> > Interface switching capability descriptor), I could not make out why
> > this is present in per LSP establishment request ? This field
> > advertises the bandwidth (both min. and max.) for various priority
> > levels (p = 0 -> 7). Furthermore, this field also contain Encoding
> > (I assume LSP encoding type) field which is already there in
> > Generalized Label Reqest object.
> > I am not able to understand why this type of information is required
> > in Per Connection Establishment Request ? Is the "switching type" field
>only
> > applicable when FA (forwarding adjacency) need to be established ?
> >
> > Regards,
> > manoj.
> >
> > _________________________________________________________________
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