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Re: [CCAMP] draft-ietf-ccamp-gmpls-g-694-lambda-labels and unique resource identification
Greg,
In the cases I'm referring to we're talking per node resource
information which typically has node (pair) local scope with the
exception of ERO and RROs. So no, I don't think an end-to-end LSP
attribute is a match.
Lou
On 11/3/2009 12:50 PM, Greg Bernstein wrote:
> Lou, do you think this information is better in a label or in some kind
> of LSP attribute? In the WSON compatibility draft we tentatively put
> similar information into a new ERO subobject for attributes. Those
> attributes included things like modulation format, FEC, and whether
> regeneration should occur at a node along the path. We didn't put them
> with the traffic descriptor since they can change along a path. I didn't
> think we should put them into labels... But I'm flexible.
>
> Regards
>
> Greg
>
> Lou Berger wrote:
>> Jonas,
>> A very good question! In the common/general setup case I think it
>> won't matter. But there are cases where it may:
>>
>> - In GMPLS we have a precedent of being able to use the label to
>> represent a specific physical resource, be it a time slot, frequency or
>> even port. If we assume that this is a function worth preserving (and I
>> believe it is, at least with today's equipment) than it is
>> desirable/required to be able to use GMPLS to control a specific laser.
>> Even a tunable one. With the current definition, this isn't possible.
>>
>> - The more practical/import case is graceful restart. In certain
>> restart cases, the restarting node may need to match particular node
>> resources (e.g., tunable lasers) against a particular frequency to
>> ensure no data loss and the restarting node may no longer have the
>> information to do the matching. In all other cases that I know about,
>> GMPLS allows for sufficient information for a node to reconstruct this
>> mapping.
>>
>> - MP to CP handover may also need to identify specific node resources
>> (e.g., tunable lasers).
>>
>> I believe these are the primary cases.
>>
>> I hope this helps,
>> Lou
>>
>> On 11/2/2009 5:35 AM, Jonas Mårtensson wrote:
>>
>>> Lou,
>>>
>>> Maybe this is a silly question but if all lasers in the system are tunable, why does it matter which one is used? Can't the node decide this locally?
>>>
>>> Regards,
>>> Jonas
>>>
>>>
>>>> -----Original Message-----
>>>> From: ccamp-bounces at ietf.org [mailto:ccamp-bounces at ietf.org]
>>>> On Behalf Of Lou Berger
>>>> Sent: den 30 oktober 2009 14:02
>>>> To: Richard Rabbat
>>>> Cc: ccamp at ietf.org
>>>> Subject: Re: [CCAMP]
>>>> draft-ietf-ccamp-gmpls-g-694-lambda-labels and unique
>>>> resource identification
>>>>
>>>> Richard,
>>>>
>>>> Okay let me try again with a specific case. If I have an rro
>>>> or ero that identifies the label (lambda) per your document,
>>>> how does a node know which laser the label corresponds to
>>>> when all lasers in the system are tunable?
>>>>
>>>> Thanks,
>>>> Lou
>>>>
>>>> On 10/29/2009 2:22 PM, Richard Rabbat wrote:
>>>>
>>>>> sorry for the lag.
>>>>> do you want to describe your use-case further in terms of what you
>>>>> can't do and your proposed change?
>>>>> thanks,
>>>>> Richard.
>>>>>
>>>>> On Thu, Oct 15, 2009 at 8:53 AM, Lou Berger <lberger at labn.net
>>>>> <mailto:lberger at labn.net>> wrote:
>>>>>
>>>>> Authors,
>>>>> Have you given any additional thought on the
>>>>>
>>>> repesentation of
>>>>
>>>>> tunable
>>>>> lasers (and unique resource identification) beyond what
>>>>>
>>>> is currently in
>>>>
>>>>> the draft? The current text is:
>>>>> If the node has a tunable wavelength transponder, the tuning
>>>>> wavelength is considered as a part of wavelength switching
>>>>> operation.
>>>>>
>>>>> In the past, labels used for TE LSPs always represented
>>>>>
>>>> a specific
>>>>
>>>>> resource that is uniquely identifiable by the node that
>>>>>
>>>> allocates the
>>>>
>>>>> label and resource. Such unique identification is
>>>>>
>>>> important/required
>>>>
>>>>> for certan restart and other corner cases. Your current
>>>>>
>>>> definition works
>>>>
>>>>> fine for fixed lasers that can only be mapped to a
>>>>>
>>>> single fiber. But,
>>>>
>>>>> the defined global label will not uniquely identify a
>>>>>
>>>> resource on a node
>>>>
>>>>> when (a) tunable lasers are used, or (b) when a node
>>>>>
>>>> supports multiple
>>>>
>>>>> fixed lasers that can be (optically) switched to a
>>>>>
>>>> particular output
>>>>
>>>>> interface.
>>>>>
>>>>> What are your thoughts on how to provide such link-scoped unique
>>>>> resource identification in the context of your draft?
>>>>>
>>>>> I don't think it'll be too difficult to address this
>>>>>
>>>> critical point, and
>>>>
>>>>> see a couple of straightforward solutions if you'd like
>>>>>
>>>> to discuss
>>>>
>>>>> off-line.
>>>>>
>>>>> Much thanks,
>>>>> Lou
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> CCAMP mailing list
>>>>> CCAMP at ietf.org <mailto:CCAMP at ietf.org>
>>>>> https://www.ietf.org/mailman/listinfo/ccamp
>>>>>
>>>>>
>>>>>
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>>>>
>>>
>>>
>>>
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>>
>
> --
> ===================================================
> Dr Greg Bernstein, Grotto Networking (510) 573-2237
>
>