RE: Label type to be used

["Ong, Lyndon" <[e-mail]>]

Hi Dimitri,

I think it was my mistake, in testing I have seen people use
FSC to describe an interface to an opaque OXC with SDH framing
when they wish to have the entire signal (minus some SDH
overhead) switched rather than sorting through individual
channels.  On further reading of draft-ietf-ccamp-gmpls-routing-09.txt
it looks like section 3.5 specifically describes this as a
case where LSC would be advertised rather than FSC, since 
there is conceptually a single wavelength, is this
still correct?

Thanks,

Lyndon

-----Original Message-----
From: [e-mail]
[mailto:[e-mail]]
Sent: Saturday, March 27, 2004 4:31 AM
To: Ong, Lyndon
Cc: 'Lou Berger'; Kireeti Kompella; [e-mail]
Subject: Re: Label type to be used


the proposal that makes a fully transparent Sonet/SDH encoded capable 
link appearing as [X,LSC] or [LSC,X], or [LSC,LSC] w/ a label defined as 
a port and/or lambda is aligned with the evolution of the definition 
towards OTN (coming from the so-called pre-OTN) technology and thus 
probably better than trying to retain the TDM value for it (with several 
flavours)

so you would have something like this when trying to harmonize in 
between the several documents we have tnat deals with this specific 
representation issue, i also think it provides the distinction you're 
asking for b/w fiber and so-called clear channels:

2.4.4. Lambda-Switch Capable

   If an interface is of type LSC, it means that the node receiving data
   over this interface can recognize and switch individual lambdas
   within the interface.  An interface that allows only one lambda per
   interface, and switches just that lambda is of type LSC.
 > This includes interfaces that only support fully transparent SONET/SDH
 > signals, as defined in [GMPLS-SONET-SDH].

[...]

2.4.7. Interface Switching Capabilities and Labels

      [PSC, PSC] - label is carried in the "shim" header [RFC3032]
 >    [TDM, TDM] - label represents a timeslot ([GMPLS-SONET-SDH],
                      [GMPLS-G709])
 >    [LSC, LSC] - label represents a G.709 OCh/lambda/port
 >    [FSC, FSC] - label represents a fiber (i.e. physical port)
 >    [PSC, TDM] - label represents a timeslot ([GMPLS-SONET-SDH],
                      [GMPLS-G709])
 >    [PSC, LSC] - label represents a G.709 OCh/lambda/port
 >    [PSC, FSC] - label represents a fiber
 >    [TDM, LSC] - label represents a G.709 OCh/lambda/port
 >    [TDM, FSC] - label represents a fiber
 >    [LSC, FSC] - label represents a fiber

 > Note: except when explicitly indicated the label encoding MUST follow 
 > the rules defined in [RFC3471] Section 3.2.

ps: in fact one sees here that for the "timeslot" case, the switching 
type TDM value equates the encoding one


Ong, Lyndon wrote:
> Hi Lou,
> 
> Your proposed text looks pretty good to me.
>  
> Side note: is there a way that the
> existing text can be clarified to distinguish
> between the case of only one lambda allowed
> on an interface and the case of fiber switching?  
> 
> Currently the text seems to allow an overlap
> in the case of a non-channelized OC-12/48/etc. as in
> a sense there is only one "lambda" but you would
> typically request fiber switching.
> 
> Cheers,
> 
> Lyndon
> 
> -----Original Message-----
> From: Lou Berger [mailto:[e-mail]]
> Sent: Friday, March 26, 2004 11:17 AM
> To: Kireeti Kompella
> Cc: [e-mail]; John Drake
> Subject: RE: Label type to be used
> 
> 
> Kireeti,
>          I think John's points on (a) and (c) are reasonable.  I think the 
> only changes needed to the draft-ietf-ccamp-gmpls-routing-09.txt to make 
> this clear are:
> 
>     2.4.4. Lambda-Switch Capable
> 
>     If an interface is of type LSC, it means that the node receiving data
>     over this interface can recognize and switch individual lambdas
>     within the interface.  An interface that allows only one lambda per
>     interface, and switches just that lambda is of type LSC.
>  >  This includes interfaces that only support fully transparent SONET/SDH
>  >   signals, as defined in [GMPLS-SONET-SDH].
> 
> and
>         [PSC, PSC] - label is carried in the "shim" header [RFC3032]
>         [TDM, TDM] - label represents a TDM time slot [GMPLS-SONET-SDH]
>  >      [LSC, LSC] - label represents a lambda/port
>         [FSC, FSC] - label represents a port on an OXC
>         [PSC, TDM] - label represents a TDM time slot [GMPLS-SONET-SDH]
>  >      [PSC, LSC] - label represents a lambda/port
>         [PSC, FSC] - label represents a port
>  >      [TDM, LSC] - label represents a lambda/port
>         [TDM, FSC] - label represents a port
>         [LSC, FSC] - label represents a port
> 
> Lou
> 
> PS This matches all but one implementation we've interoperated with.
> 
> At 01:49 PM 3/26/2004 -0500, John Drake wrote:
> 
> 
> 
>>>-----Original Message-----
>>>From: Kireeti Kompella 
>>
>>[<mailto:[e-mail]>mailto:[e-mail]]
>>
>>>Sent: Thursday, March 18, 2004 9:58 AM
>>>To: [e-mail]
>>>Subject: Label type to be used
>>>
>>>Hi,
>>>
>>>Arthi and Lou pointed out the following typos in the GMPLS routing doc
>>>(draft-ietf-ccamp-gmpls-routing-09.txt) which is now in the RFC
>>>Editor's queue:
>>>
>>>In section 2.4.7 is the following table defining the type of label
>>>for various combinations of switching types:
>>>
>>>      [PSC, PSC] - label is carried in the "shim" header [RFC3032]
>>>      [TDM, TDM] - label represents a TDM time slot [GMPLS-SONET-SDH]
>>>      [LSC, LSC] - label represents a lambda
>>>      [FSC, FSC] - label represents a port on an OXC
>>>      [PSC, TDM] - label represents a TDM time slot [GMPLS-SONET-SDH]
>>>      [PSC, LSC] - label represents a lambda
>>>      [PSC, FSC] - label represents a port
>>>      [TDM, LSC] - label represents a lambda
>>>      [TDM, FSC] - label represents a port
>>>      [LSC, FSC] - label represents a port
>>>
>>>The one at issue is [PSC, LSC]; above it says that the label
>>>represents a lambda; and in the case of [PSC, TDM] with a fully
>>>transparent signal, the above indicates the label represents a TDM
>>>time slot.  The proposal is to change this to:
>>>
>>>      [PSC, PSC] - label is carried in the "shim" header [RFC3032]
>>>      [TDM, TDM] - label represents a TDM time slot [GMPLS-SONET-SDH]
>>>      [LSC, LSC] - label represents a lambda
>>>      [FSC, FSC] - label represents a port on an OXC
>>>      [PSC, TDM] - fully transparent signal: label represents a port
>>>                   ("transparency" is defined in [GMPLS-SONET-SDH])
>>>      [PSC, TDM] - non-transparent signal: label represents a TDM time
>>>                   slot [GMPLS-SONET-SDH]
>>>      [PSC, LSC] - label represents a port
>>>      [PSC, FSC] - label represents a port
>>>      [TDM, LSC] - label represents a lambda
>>>      [TDM, FSC] - label represents a port
>>>      [LSC, FSC] - label represents a port
>>>
>>>Please respond by Friday 3/26, 5pm PST with comments on:
>>>
>>>a) do you agree with the above change?
>>
>>[John Drake]
>>
>>I don't have a problem with the [PSC, LSC] change but I don't
>>understand the distinction between transparent and non-transparent
>>TDM as it pertains to GMPLS routing.  As I indicated in a previous
>>e-mail, I think the transparent TDM case should be handled with a
>>switching type of LSC and an encoding type of SDH/SONET, and I think
>>that this should be specified in the SDH/SONET I-D, where the distinction
>>between transparent and non-transparent TDM is defined, rather than in
>>this document.
>>
>>
>>>b) in your implementation today, what do expect the label to represent
>>>   i) in the case of [PSC, LSC]?
>>
>>[John Drake]
>>
>>Port/lambda
>>
>>
>>>   ii) in the case of [PSC, TDM] with a fully transparent signal?
>>>c) if you implement as the draft says, would it be a hardship to change
>>>   this?
>>
>>[John Drake]
>>
>>N/A.  Labels for SDH/SONET are defined in the SDH/SONET I-D and it's pretty
>>clear about which types of labels are in the transparent and non-transparent
>>TDM cases.
>>
>>
>>>If we can get closure on this, I'll take up the task of modifying the
>>>pending RFC with the ADs.
>>>
>>>Kireeti.
>>>-------
> 
> 
> 

-- 
Papadimitriou Dimitri
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