John- Obviously the benefits or harms of giving a global meaning to a lambda label requires study, but your particular example is not a good one: If one really wants to have a preference for a specific wavelength channel among multiple parallel channels of the same wavelength, bundling should not be exercised in the first place. Thanks, Payam -----Original Message----- From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org]On Behalf Of Drake, John E Sent: Monday, October 31, 2005 10:36 AM To: Shiba, Sidney; dpapadimitriou@psg.com Cc: Adrian Farrel; richard.rabbat@us.fujitsu.com; ccamp@ops.ietf.org Subject: RE: comments on draft-shiba-ccamp-gmpls-lambda-labels-00.txt Sidney, But there's nothing in your picture that requires an absolute end-end global wavelength. The existing GMPLS solution with relative wavelengths of local significance should work just fine. As I said in my previous note, your method precludes combining two or more parallel WDM links into a single TE link. Thanks, John > -----Original Message----- > From: Shiba, Sidney [mailto:sidney.shiba@us.fujitsu.com] > Sent: Monday, October 31, 2005 7:25 AM > To: Drake, John E; dpapadimitriou@psg.com > Cc: Adrian Farrel; richard.rabbat@us.fujitsu.com; ccamp@ops.ietf.org > Subject: RE: comments on draft-shiba-ccamp-gmpls-lambda-labels-00.txt > > Hi John, > > Optical switches based on Wavelength Selective Switch (WSS) technology > requires the wavelength information for switching. This technology is NOT > wavelength agnostic. > > | | > | wdm | wdm > |2 |2 > --------- --------- > wdm 1| optical |3 wdm 1| optical |3 wdm > --------| switch |------------| switch |--------- > | (WSS) | | (WSS) | > --------- --------- > |4 |4 > | wdm | wdm > | | > > Note that the figure above shows an example of two optical switches > interconnect > by a single WDM fiber. In this example, each optical switch can be connect > to 4 > other optical switches. > > As you can see, the optical ports information do not provide enough > information > for wavelength switching. > > Hope that clarifies the application requirement. > > Thanks, > > Sidney > > > -----Original Message----- > > From: Drake, John E [mailto:John.E.Drake2@boeing.com] > > Sent: Friday, October 28, 2005 5:33 PM > > To: dpapadimitriou@psg.com; Shiba, Sidney > > Cc: Adrian Farrel; richard.rabbat@us.fujitsu.com; ccamp@ops.ietf.org > > Subject: RE: comments on draft-shiba-ccamp-gmpls-lambda-labels-00.txt > > > > > > Hi, > > > > Below is the text of an e-mail is sent to the Ethernet/GMPLS mailing > > list. > > > > Upon reflection I am not sure using a real wavelength value makes much > > sense. Between a pair of adjacent nodes, there may be > > multiple pairs of > > switch ports in the same TE link that support a given frequency. If a > > real wavelength value is used, how do the two nodes agree on > > which pair > > of switch ports to use? > > > > Furthermore, the amount of configuration is the same - you > > still need to > > configure the wavelength of each switch port. > > > > Thanks, > > > > John > > ============================================================== > > ========== > > ==== > > Adrian, > > > > In the transparent photonic lambda switch case, the labels also have > > only local significance. When an LSP is established, the input ports, > > as identified with local labels, are cross-connected to the output > > ports, as identified with local labels. > > > > There is just extra configuration to identify, using strictly local > > identifiers, the wavelength associated with the all of the switch's > > ports, and an additional CAC requirement that the wavelengths of the > > input and output ports are the same. > > > > Thanks, > > > > John > > > > > > > -----Original Message----- > > > From: dimitri papadimitriou [mailto:dpapadimitriou@psg.com] > > > Sent: Thursday, October 27, 2005 10:03 AM > > > To: Shiba, Sidney > > > Cc: dimitri.papadimitriou@alcatel.be; Adrian Farrel; > > > richard.rabbat@us.fujitsu.com; ccamp@ops.ietf.org > > > Subject: Re: comments on > > draft-shiba-ccamp-gmpls-lambda-labels-00.txt > > > > > > shiba - see inline for some additional hints: > > > > > > >>Shiba, Sidney wrote: > > > >> > > > >>>Adrian, Dimitri, > > > >>> > > > >>>Thanks for reviewing these I-D. > > > >>> > > > >>>Wavelength continuity constraint does require the use of > > semanticful > > > >>>label whether it is spectral or index. > > > >> > > > >>=> see my reply to adrian on this specific point > > > >> > > > >>>I agree with Dimitri that the > > > >>>wavelength indexing requires document updating each time a new > > > >>>spectrum is introduced. > > > >> > > > >>=> indeed and in addition it requires updating the already > > > >>signaled path > > > >> > > > >>>The use of spectral label provides self maintainance, i.e., > > > >>>no need to update any document and the use of the nominal value > > > >>>provides a common semantic ground. > > > >> > > > >>=> what do you mean by self-maintenance - would you provide a > > > >>bit more detail > > > > > > > > [Sidney]What I've meant here was that it was not necessary to > > > > update any document when new wavelengths are inventoried. In the > > > > case of indexing approach, it would require the > > wavelength indexing > > > > document to be updated with implementation impacts. > > > > > > > > In the case, the nominal value is used, there is no need for > > > > documentation update. > > > > > > ok - what you mean here is that you are going to make use of the > > already > > > defined C-Type 2 - what about the specific encoding of the > > value space > > ? > > > > > > >>=> now i have a more specific question before being light-up > > > >>how do you know the frequency that you can support ? > > > > > > > > [Sidney] Some new technologies integrate optical switch and > > mux/demux > > > > capabilities, which allows the equipment to know the spectrum it > > > supports. > > > > > > indeed - but the question is what does happen if the > > "detected" values > > > (during initialization) do not match the nominal values ? you don't > > > initialize then ? > > > > > > >>if these differ from the nominal values how are you going to deal > > with > > > these > > > >>discrepancies ? > > > > > > > > [Sidney] These new technologies uses the nominal value as > > reference. > > We > > > can say > > > > that a lightpath wavelength is identified by its nominal value. If > > the > > > equipment > > > > is drifting from this nominal value, it is considered as > > a failure. > > > > > > ok - but if the deviation is such you have overlap - how the control > > > plane is going to be able to detect such failure ? > > > > > > >>this said i am not necessarily sure that having to > > maintain the data > > > plane > > > >>specifics as part of the control plane is really helping > > > >>operations (is this method not just duplicating complexity ?) > > > > > > > > [Sidney] The wavelength is WDM specific as much as the SUKLM label > > > encoding > > > > is for SONET. The wavelegth/frequency nominal value is used to > > identify > > > the > > > > facilities to cross-connect. > > > > > > there is an equivalence but there is also a major difference, the > > > structure is invariant independently of the state of the > > network, with > > > spectral value space you may have labels that become unavailable due > > to > > > non-local usage of wavelength in the network > > > > > > hence, there is also no real coupling to the data plane more than > > > knowing the type of interface and some generic capabilities > > > > > > >>>I'm not sure if the draft needs to be updated before the > > > >>>face-to-face meeting or after all comments are collected. Please > > > advise. > > > >> > > > >>=> suggest to keep discussion on - document update can be > > > >>performed at a later stage > > > > > > thanks, > > > - dimitri. > > > > > > >>>>-----Original Message----- > > > >>>>From: owner-ccamp@ops.ietf.org > > [mailto:owner-ccamp@ops.ietf.org]On > > > >>>>Behalf Of Adrian Farrel > > > >>>>Sent: Thursday, October 27, 2005 4:45 AM > > > >>>>To: dpapadimitriou@psg.com; dimitri.papadimitriou@alcatel.be; > > > >>>>ccamp@ops.ietf.org > > > >>>>Subject: Re: comments on > > > >> > > > >>draft-shiba-ccamp-gmpls-lambda-labels-00.txt > > > >> > > > >>>> > > > >>>>Dimitri, > > > >>>> > > > >>>>Thanks for your work reviewing these recent I-Ds. It is > > > >>>>really valuable > > > >>>>and I'd welcome other people doing similar reviews. > > > >>>> > > > >>>> > > > >>>> > > > >>>>>there is a specific point to be clarified in this document: > > > >>>>> > > > >>>>>semanticless vs semanticful label (even here there is a > > distinction > > > >>>>>between spectral vs indexes i.e. using the wavelength index) > > > >>>>> > > > >>>>>domain-wide vs link local significant label > > > >>>> > > > >>>>Without being too picky, I think all labels are semanticful > > > >>>>otherwise, we > > > >>>>would not know what resource they refered to. > > > >>>> > > > >>>>So the point reduces to whether the scope of the semantics > > > >>>>are link-local > > > >>>>or wider. > > > >>>> > > > >>>> > > > >>>> > > > >>>>>so, the comparison from this perspective with TDM labels is > > > >>>> > > > >>>>difficult to > > > >>>> > > > >>>> > > > >>>>>parse, the latter is semanticful but link local > > > >>>>> > > > >>>>>now, i don't specifically see what has changed the late 90's, > > early > > > >>>>>y2k's, to have a change in the wavelength label definition; > > > >>>> > > > >>>>This is the question I would like to get to the bottom of. In > > > >>>>other words: > > > >>>>do we need this function? > > > >>>> > > > >>>>It seems to me that the question being asked is this: > > > >>>> > > > >>>> If I want to compute a path that has some form of wavelength > > > >>>> constraints, what information do I need access to? > > > >>>> > > > >>>>Another question might be: > > > >>>> > > > >>>> If I want to signal a path with wavelength constraints what > > > >>>> information do I need to include in the signaling message? > > > >>>> > > > >>>> > > > >>>>I'd suggest that when we started on GMPLS, we were > > > >> > > > >>enthusiastic about > > > >> > > > >>>>transparent optical networks, but we were not properly > > > >>>>focusing wavelength > > > >>>>constraints because lambda-switching PXCs didn't take off. > > > >>>>Therefore we > > > >>>>didn't examine the requirements for wavelength constraints in > > > >>>>routing and > > > >>>>signaling. The authors of this I-D are claiming new hardware > > > >>>>requirements > > > >>>>for the same function. > > > >>>> > > > >>>> > > > >>>> > > > >>>>>there are > > > >>>>>several solution possible > > > >>>>> > > > >>>>>- absolute values: the freq. of the wavelength: difficult to > > adopt > > > >>>>>because referenced values are nominal and knowing all > > interactions > > > >>>>>between wavelengths this knowledge is at the end of little > > > >> > > > >>practical > > > >> > > > >>>>>usage; (introduces implicit ordering) > > > >>>>> > > > >>>>>- indexed values: the # of the wavelength: it does not > > > >> > > > >>provide for a > > > >> > > > >>>>>future proof label space for inst. in case new frequencies > > > >>>> > > > >>>>are inserted > > > >>>> > > > >>>> > > > >>>>>in the grid (introduces explicit ordering) > > > >>>>> > > > >>>>>- diff. values e.g. freq spacing starting from a reference > > > >>>> > > > >>>>value: pauses > > > >>>> > > > >>>> > > > >>>>>the question of the reference value and does suffer from the > > former > > > >>>>>issue (introduces implicit ordering) > > > >>>>> > > > >>>>>- the solution available today - cumbersome in some > > control plane > > > >>>>>operations (e.g. label set translation) and not easy to > > > >>>> > > > >>>>troubleshoot but > > > >>>> > > > >>>> > > > >>>>>independent of any physical consideration (spectral), scale to > > any > > > >>>>>number of wavelength per fiber, does not introduce any > > > >> > > > >>ordering, the > > > >> > > > >>>>>most flexible (since allowing each system to maintain its > > specific > > > >>>>>control operations) and the less constraining since maintaining > > the > > > >>>>>control plane operations independent of any data plane > > specifics > > > >>>>> > > > >>>>> > > > >>>> > > > >>>><http://www.ietf.org/internet-drafts/draft-shiba-ccamp-gmpls-l > > > >>> > > > >>>ambda-labels > > > >>>-00.txt> > > > >>> > > > >>>. > > > >>> > > > >> > > > > > > > > . > > > > > >
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