Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid
Iftekhar Hussain <IHussain@infinera.com> Wed, 19 March 2014 17:58 UTC
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From: Iftekhar Hussain <IHussain@infinera.com>
To: "Zhangxian (Xian)" <zhang.xian@huawei.com>, Ramon Casellas <ramon.casellas@cttc.es>
Thread-Topic: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid
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Date: Wed, 19 Mar 2014 17:58:42 +0000
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Subject: Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid
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Hi Xian and Ramon, Personally I don’t see anything wrong in the text asking for a clarification on this ambiguity of a standard. However, if abbreviating the text will get the question across more clearly and get the required clarification, I am okay to use text suggested by Xian with small addition. “G.872 defines that a media channel may carry more than one OCh-P signal. It also defines that a network media channel is a specific use of media channel with a single OCh-P. Clarification is needed on the application of network media channel and media channel given that a media channel is a superset and can support the network media channel functionality. ” Thanks, Iftekhar From: Zhangxian (Xian) [mailto:zhang.xian@huawei.com] Sent: Tuesday, March 18, 2014 7:31 PM To: Iftekhar Hussain; Ramon Casellas Cc: ccamp@ietf.org Subject: Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid Hi, Ramon, Iftekhar I am not sure either why we ask that question in the last point (i.e., May a network media channel be defined as associated with more than one OCh-P?) and we can expect a “No” answer from current G.872 specification. But I am also concerned about directly using the text provided by Iftekhar since it implies “we are disagreeing with current G.872 and would suggest a change to this Rec.”. There is nothing with the text itself but this would not be appropriate in a liaison. How about condensing it to the following? “G.872 defines that a media channel may carry more than one OCh-P signal. It also defines that a network media channel is a specific use of media channel with a single OCh-P. Clarification is needed on the application of network media channel.” Regards, Xian From: CCAMP [mailto:ccamp-bounces@ietf.org] On Behalf Of Iftekhar Hussain Sent: 2014年3月19日 5:52 To: Ramon Casellas; ccamp@ietf.org Subject: Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid Hi Ramon, “- A NMC as bound to 1 OCh-P by definition of the in-force G.872. - a Media channel may carry more than 1 OCh-P, but MC != NMC” The above looks fine and we have the same understanding. What needs clarification is that (a) is NMC required? If so why? Note that MC already is a superset of NMC. The bullet didn’t have whole text we prefer the following full text in the liaison for clarity: “G.872 defines that a media channel may carry more than one OCh-P signal. It also defines that a network media channel is a specific use of media channel with a single OCh-P. Clarification is needed on the definition and application of network media channel. If intent is that there is always an end-to-end network media channel, then it should support multiple OCh-Ps. Alternatively, eliminate the network media channel definition altogether, in favor of always using the media channel term which already supports this capability. Requiring a one-to-one mapping between OCh-P and network media channels would be restrictive in cases where multiple OCh-P need to go between the same destinations. The most spectrally efficient packing of them may not allow each OCh-P to use its own network media channel within the defined flexible grid granularity” Please let us know if any further clarification is required. Thanks, Iftekhar From: Ramon Casellas [mailto:ramon.casellas@cttc.es] Sent: Tuesday, March 18, 2014 3:42 AM To: ccamp@ietf.org Subject: Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason regarding Flexi-grid Dear all, Thanks for your comments. Below a revised text, still open for discussion. Personally, I am afraid i still don't fully grasp the last bullet, so please elaborate a bit more or re-formulate (Iftekhar, Rajan?) [Editor: In my limited understanding: - A NMC as bound to 1 OCh-P by definition of the in-force G.872. - a Media channel may carry more than 1 OCh-P, but MC != NMC - With a Optical Tributary Signal (OTS) there is a 1:1 mapping between OTS:NMC. - A particular case of OTS is an OCh-P For my understanding, can a OTS group multiple OCh-P?] Thanks R. -------------------------------------------------------- In order to progress our work on the draft “Framework and Requirements for GMPLS based control of Flexi-grid DWDM networks” [1] and subsequent solution documents within the IETF CCAMP working group, we would like to receive your comments/clarification as follows (addressing ITU-T experts within Q6, Q12 and Q14): • Please comment on future changes regarding the values of nominal central frequency (NCF) granularity [NCFG, currently 6.25 GHz] and slot width granularity [currently 12.5 GHz], as defined in G.694.1. Is ITU-T considering alternative values (e.g. 3.125 GHz) in the foreseeable future? If yes, is it correct to assume, that the following always holds, w.r.t. slot width granularity and NCF granularity? SWG = 2 * NCFG [Note: changes in these values may require additional code-points within encodings at control plane protocols] • Clarification on the maximum values of the slot width (m parameter) and the expected use cases (e.g. to cover the whole C band). Knowing these values is required since it has an impact on their encoding. • Opinion / Clarification on the data plane “hitless” and “hitless” capabilities. Is ITU-T considering any hitless procedure, such as resizing / restoration of a network media channel (in terms of its frequency slot)? Examples of cases where hitless capabilities may be considered are: o Case 1: Recovery where the new network media channel uses a diverse path o Case 2: shrink / enlarge frequency slot width, invariant NCF (n) o Case 3: shift the NCF (n), maintaining the frequency slot width (m) • Clarification on the case where an OTUCn is carried by a (co-routed) group of network media channels which must be managed as a single entity (including set up, recovery, and hardware cross-connection). If this is in scope, what is the estimated availability of ITU-T Recommendation covering this new requirement? [Note: CCAMP has considered so far the following requirement: “The control plane architecture SHOULD allow multiple media channels to be logically associated. The control plane SHOULD allow the co-routing of a set of media channels logically associated”. If ITU-T covers this new requirement, it may have an impact on the control plane representation and related procedures] • Current in-force G.872 recommendation defines that a media channel may carry more than one OCh-P signal. It also defines that a network media channel is a specific use of media channel with a single OCh-P. May a network media channel be defined as associated with more than one OCh-P? [1] http://tools.ietf.org/html/draft-ietf-ccamp-flexi-grid-fwk-01
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Iftekhar Hussain
- [CCAMP] Draft Text for ITU-T - CCAMP Liason regar… Oscar González de Dios
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Huub van Helvoort
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… fu.xihua
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… fu.xihua
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Jonas Mårtensson
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Zhangxian (Xian)
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Ramon Casellas
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Ramon Casellas
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Fatai Zhang
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Iftekhar Hussain
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Iftekhar Hussain
- [CCAMP] FW: Draft Text for ITU-T - CCAMP Liason r… Zhangxian (Xian)
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Zhangxian (Xian)
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Ramon Casellas
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Iftekhar Hussain
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… BRUNGARD, DEBORAH A
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… Iftekhar Hussain
- Re: [CCAMP] Draft Text for ITU-T - CCAMP Liason r… wang.qilei
- [CCAMP] Final Text ITU-T Liaison flexi-grid // Wa… Ramon Casellas