Re: Updated Draft Liaiosn to Q6/15
Giovanni Martinelli <giomarti@cisco.com> Tue, 10 March 2009 09:18 UTC
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Date: Tue, 10 Mar 2009 10:18:50 +0100
From: Giovanni Martinelli <giomarti@cisco.com>
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To: "O'Connor, Don" <don.oconnor@us.fujitsu.com>
CC: Adrian Farrel <adrian@olddog.co.uk>, ccamp@ops.ietf.org
Subject: Re: Updated Draft Liaiosn to Q6/15
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O'Connor, Don wrote: > Adrian > > Can you please remove this text > > " However, if an implementer chooses to measure impairments > on their device, this should not be prohibited, and should be > accommodated." > > This should be determined by ITU not CCAMP. CCAMP cannot generate > standards that imply ROADM data plane functionality. If any optical > impairments are measured by ROADMs, ITU must first generate the > necessary standard > Although I understand there could be some precedences I would not the remove the text. In principle the RWA problem try to catch some data plane constrains as well. Cheers, G > Regards > > Don > > -----Original Message----- > From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On > Behalf Of Adrian Farrel > Sent: Monday, March 09, 2009 4:50 PM > To: ccamp@ops.ietf.org > Subject: Updated Draft Liaiosn to Q6/15 > > Hi, > > Had some comments off-list. > > New version with minor changes... > > === > > Dear Peter, > > CCAMP experts are looking forward to our joint meeting with Q6/5 on > March > 20th to discuss optical impairments and the control plane operation of > wavelength switched optical networks (WSONs). > > This liaison is to summarise the activity within CCAMP on this subject > so > far and to set out our objectives for this work. > > As you will be aware, the GMPLS control plane is designed to provide a > dynamic control plane for a variety of switching technologies. Amongst > these > is the "lambda switch capable" data plane where devices are OEOs, > ROADMs, > and photonic cross-connects (PXCs). In fact, lambda switching was the > technology that led to the development of MPLS from the packet switching > > MPLS control plane. > > The IETF's CCAMP working group is the design authority for all > extensions to > the GMPLS family of protocols. > > The original work on lambda switching networks within CCAMP recognised > that > there is a subset of optical networks in which it is possible to > disregard > optical impairments and where the number of regeneration points is high. > In > these environments, path computation can be performed on a reachability > graph, and lambda conversion can be performed as necessary within the > network. > > As PXCs were introduced into WSONs, it remained the case that optical > impairments could be disregarded by the control plane. Where necessary, > optimal impairment-aware paths could be computed off-line and supplied > to > the control plane, leaving the control plane to handle establishment of > connections and recovery after failure. Failure recovery scenarios might > > lead to contention for wavelengths or suboptimal optical paths, but > these > could be handled by crankback within the signaling protocol. > > More recent work on WSONs indicates that the proportion of pure optical > devices (ROADMs and PXCs) is increasing. This means that it is necessary > to > compute paths that offer end-to-end lambda continuity. This problem > (called > the routing and wavelength assignment (RWA) problem) must be solved, and > may > be compounded by devices with limited cross-connect capabilities (for > example, with glass-through, a limited OEO matrix, or restricted > port-to-port capabilities). In approaching this problem it is convenient > if > there is a common identification scheme for wavelengths across the whole > > network (previously, wavelength identification was a local matter > between > the nodes at the ends of each link). To aid with this, the CCAMP working > > group has developed > http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-g-694-lambda- > labels-03.txt > that provides a protocol-independent encoding for wavelengths in a way > that > is compliant with G.694. Further work on this problem space can be seen > in > the following CCAMP documents: > > "Framework for GMPLS and PCE Control of Wavelength Switched Optical > Networks > (WSON)" > http://www.ietf.org/internet-drafts/draft-ietf-ccamp-rwa-wson-framework- > 01.txt > > "Routing and Wavelength Assignment Information Model for Wavelength > Switched > Optical Networks" > http://www.ietf.org/internet-drafts/draft-ietf-ccamp-rwa-info-01.txt > > "Routing and Wavelength Assignment Information Encoding for Wavelength > Switched Optical Networks" > http://www.ietf.org/internet-drafts/draft-ietf-ccamp-rwa-wson-encode-00. > txt > > CCAMP participants have further identified cases where they believe it > would > be helpful to consider optical impairments during the control plane > operation of a WSON. This gives rise to four distinct deployment > scenarios: > > 1. No concern for impairments or lambda continuity. > (Original GMPLS) > 2. No concern for impairments, but lambda continuity is > important. (The RWA problem) > 3. Concern for "basic" impairments > 4. Concern for "advanced" impairments > > In focusing on the third of these categories, CCAMP intends to base its > work > on G.680 and related recommendations with the following understanding: > - G.680 (et al.) provides a complete list of simple constraints > - Where G.680 refers to "single vendor" domains, it does not > mean single manufacturer, but rather "single system integrator". > That is, the equipment is not "plug and play", but has been > tested to interoperate and the network has been planned. > - There is no requirement to measure impairments. > - Many networks are engineered such that configured > impairment values are enough information > - Measuring can often produce ambiguous values > - Equipment to perform measurement may be expensive > However, if an implementer chooses to measure impairments > on their device, this should not be prohibited, and should be > accommodated. > > With this in mind, CCAMP is looking to Q6/15 to work as a partner in > establishing: > - the complete list of impairments suitable for this type of network > - and the complete list of Recommendations to use as references > - the rules by which such impairments are accumulated along a path > - generic encodings and ranges of values for the impairments > > For reference, some early work on impairment-aware GMPLS is listed > below. > This work is not yet adopted as CCAMP work, but is likely to form the > basis > of such work once we have discussed the way forward with Q6/15. > > "A Framework for the Control of Wavelength Switched Optical Networks > (WSON) > with Impairments" > http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wson-impairmen > ts-02.txt > > "Information Model for Impaired Optical Path Validation" > http://www.ietf.org/internet-drafts/draft-bernstein-wson-impairment-info > -00.txt > > Looking forward to a profitable meeting, > Deborah Brungard and Adrian Farrel > CCAMP Working Group Co-Chairs > > > > >
- Re: Updated Draft Liaiosn to Q6/15 Greg Bernstein
- Re: Updated Draft Liaiosn to Q6/15 Giovanni Martinelli
- RE: Updated Draft Liaiosn to Q6/15 Malcolm Betts
- RE: Updated Draft Liaiosn to Q6/15 Malcolm Betts
- Re: Updated Draft Liaiosn to Q6/15 Giovanni Martinelli
- RE: Updated Draft Liaiosn to Q6/15 O'Connor, Don
- Updated Draft Liaiosn to Q6/15 Adrian Farrel