[CCAMP] FW: RESPONSE TO => FW: Signaling extensions for G.709 - draft-khuzema-ccamp-gmpls-signaling-g709-00.txt

[Rajan Rao <[e-mail]>]

Fatai,



Interesting discussion. Please find the response below.



Authors of draft-khuzema



-----Original Message-----
From: Fatai Zhang [mailto:[e-mail]]
Sent: Friday, October 29, 2010 1:26 PM
To: Rajan Rao; Khuzema Pithewan; Mohit Misra; Ashok Kunjidhapatham
Cc: [e-mail]; Biao Lu
Subject: Re: [CCAMP] Signaling extensions for G.709 - draft-khuzema-ccamp-gmpls-signaling-g709-00.txt



Hi Rajan,



You said there are the following differences between two drafts:

-  G.709 multi-stage multiplexing (v3 & beyond)

-  NMC treatment (ref to section-4 in the draft)

-  Support for VCAT (NVC >1 )

- TPN format



We have to repeat that there is not much substantial difference between two drafts except multi-stage muxing.



We don't want to talk more on "NMC", "NVC", "TPN", because they have been discussed before and it is quite easy for [draft-zhang] to do that. For example, for NMC, there is an editors note in the previous versions  such as 04 version to discuss NMC stuff (and some people opposed to deprecate NMC). For NVC, it is obviously that [draft-zhang] can support it.



Now we can focus your key driver-multi-stage muxing.



1) At page 3, in the list of added OTN features is present explicitly the "Multi-stage ODU Multiplexing". Actually, multi-stage is not present at all as requirement/feature in G.709. Our intention to postpone technical solution regarding multi-stage multiplexing is justified by on going ITU-T SG15 progress. Before thinking about specific signaling and routing solutions we need to have stable ITU-T requirements. This why in all our common drafts (FWK, Info-Model, Routing and Signaling drafts) we just placed some placeholder on the subject.



[AK, KP, RR] {

 Your understanding is not correct. Please refer to Figure-7-1A (G.709 12/2009). It clearly shows multi-stage muxing. G.709 doesn't mandate it has to be single stage. The G.709 OTN frame formats fully support this capability.



Vendors may choose to implement limited number of muxing levels. This should not impact the signaling solution we come up with.

}





2) We are confused by your simplified multi-stage muxing label distribution rule



There is no detailed text to describe multi-stage muxing label distribution procedures in your draft and your explaination in your below mail just focuses on one single node rather than how to create the end-to-end LSP.



It is known that GMPLS standard procedure impose that every node has to allocate a label/labels consistent with the Generalized Label Request. Very important: Generalized Label Request cannot be changed during signaling path.

[AK, KP, RR]{

  There is no disagreement here.  Generalized label request doesn't change. It is fully consistent with RFC-4328. This is precisely the reason why we spelled out NMC treatment with ODU2e case (ref to section 4.0 in draft-khuzema).



Multi-stage label concept is enforced on the Generalized Label only. This affects only the labels exchanged between the peers. This does not affect the Generalized Label Request  which is relayed end-to-end.

}



For example, taking ODU1-ODU2-ODU3 two-stage muxing, which means that we need a service ODU1 that will be muxed into ODU2 and then ODU3. Assume the path is A-B-C-D-E, in node B and node D will finish the two-stage muxing/demuxing. How you to create the LSP? how you to distribute the labels in Node B, C, D? What is the traffic parameters will be transmitted in the nodes B, C, D and nodes A, E?



[AK, KP, RR]{



There are 2 ways to handle this case: with FA or without FA. Both are explained with an example below



 We have expanded the example as follows:



          A---------------B---------------C---------------D----------------E

                OTU1             OTU3            OTU3          OTU1



 Assume that:

   - ODU0 LSP is created from A to E.

   - ODU3 links between B-C and C-D support TS-Granularity of 2.5G only.  Hence ODU0 service can be supported on this interface only through ODU3-ODU2-ODU0  or ODU3-ODU1-ODU0. Say we pick ODU3-ODU2-ODU0 for this example.

-    Generalized Label request in this case will be for ODU0 only.



Case-1) Without FA: The ODU2 layer created on B-C and C-D does not run between B & D.  They terminate between B-C and C-D respectively.  Following is the layering and multi-stage label that needs to exchanged between the nodes.





          A---------------B---------------C---------------D----------------E

                OTU1             OTU3            OTU3          OTU1



          |<--------------------------------------------------------------->|

          |                           ODU0                                 |

          |<---------------->|                               |<---------------->|

          |       ODU1     |                               |      ODU1     |

          |                |<--------------->|<---------------->|               |

          |                |      ODU2    |      ODU2      |               |

          |                |<--------------->|<---------------->|               |

          |                |      ODU3    |      ODU3      |               |

          |                |              |                |               |

Label     |                |              |                |               |

#of stages|        1       |         2    |         2      |         1     |

Stage-1   |   ODU1<--ODU0   |   ODU3<--ODU2  |   ODU3<--ODU2   |    ODU1<--ODU0  |

Stage-2   |                |   ODU2<--ODU0  |   ODU2<--ODU0   |               |

------------------------------------------------------------------------------



Case-2) With FA:

If ODU2 needs to run between B---D, we need to create an FA-LSP for ODU2 layer & this will be a TE-Link by itself. In that case, ODU0 will be routed directly over ODU2 - which is single stage only (no need of multi-stage label in that case).



The creation of FA-LSP is outside the scope of our draft.

}

Thanks

Ashok/Khuzema/Rajan



Thanks,



Authors of [draft-zhang-ccamp-gmpls-evolving-g709-06.txt]









----- Original Message -----

From: "Rajan Rao" <[e-mail]>

To: "Fatai Zhang" <[e-mail]>; "Khuzema Pithewan" <[e-mail]>; "Mohit Misra" <[e-mail]>; "Ashok Kunjidhapatham" <[e-mail]>

Cc: <[e-mail]>; "Biao Lu" <[e-mail]>

Sent: Thursday, October 28, 2010 2:17 PM

Subject: RE: [CCAMP] Signaling extensions for G.709 - draft-khuzema-ccamp-gmpls-signaling-g709-00.txt





Fatai,



Please see response inline.



thanks

Rajan

________________________________________

From: Fatai Zhang [[e-mail]]

Sent: Wednesday, October 27, 2010 6:08 PM

To: Rajan Rao; Khuzema Pithewan; Mohit Misra

Cc: [e-mail]; Zhang, Fatai

Subject: Re: [CCAMP] Signaling extensions for G.709 - draft-khuzema-ccamp-gmpls-signaling-g709-00.txt



Hi Rajan,



Happy to see your draft, but except multi-stage muxing supported in your draft,  I don't see any substantial difference between your draft and [draft-zhang-ccamp-gmpls-evolving-g709-06.txt].



[Rajan]{

Multi stage muxing is one of the key drivers for  signaling extensions. Any solution is incomplete without this. The label format proposed is intended to support G.709-v3 & future OTN extensions. Section 5.2 in  draft-ietf-ccamp-gmpls-g709-framework-03  touches on this aspect!!



We see following key differences between the drafts:

 Our draft addresses

-          G.709 multi-stage multiplexing (v3 & beyond)

-          NMC treatment (ref to section-4 in the draft)

-          Support for VCAT (NVC >1 )

}



You may say that TPN info is incorporated into label Object, but you know it is easy for [draft-zhang-ccamp-gmpls-evolving-g709-06.txt] to do that and we already stated it in the slides for IETF78th meeting ( we just make the door open at this moment and there are some advantages to decouple TPN and Label).



[Rajan]{

The key thing here is the mux layers.  The TPN in label object is intended to address per mux layer case.... more efficient.

I think this should be captured in framework doc (section 3.1.2.1in framework doc doesn't cover hierarchy aspect clearly).

}



In addtion, for multi-stage muxing, I really suspect that it can be resolved so easily, because it is MLN stuff and it needs to indicate how to create the infrastructure FA-LSP (See RFC4206 and 4206bis). If it can be done in this way as your draft describes, we all will be much happy.



[Rajan]{

The label structure we have defined is to address muxing levels of G.709.  This is not solving MLN using FA. i.e. it doesn't result in creation of FA automatically. There is no FA involved or intended here (out of scope). Please refer to section-3.0 in https://datatracker.ietf.org/doc/draft-ashok-ccamp-gmpls-ospf-g709/.



 For example,  we need 3 labels to create an ODU0 LSP with following muxing structure on a given TeLink



Muxing hierarchy on a TeLink: OTU3-ODU3-ODU2-ODU1-ODU0



Num-of-mux-stages = 3

Stage-1 - Label#1: for ODU2 layer with 8 out of 32 bits set

Stage-2 - Label#2: for ODU1 layer with 2 out of 8 bits set

Stage-3 - Label#3: for ODU0 layer with 1 out of 2 bits set



}





Best Regards



Fatai



----- Original Message -----

From: Rajan Rao<mailto:[e-mail]>

To: [e-mail]<mailto:[e-mail]>

Cc: Khuzema Pithewan<mailto:[e-mail]> ; Mohit Misra<mailto:[e-mail]>

Sent: Wednesday, October 27, 2010 5:26 AM

Subject: [CCAMP] Signaling extensions for G.709 - draft-khuzema-ccamp-gmpls-signaling-g709-00.txt



Hi,



We have a draft on "GMPLS Signaling extensions for OTN" available for review.  It can be accessed from the following link:

http://www.infinera.com/rfc/draft-khuzema-ccamp-gmpls-signaling-g709-00.txt

The above draft is not on IETF repository as we missed the submission deadline.  We will submit to IETF as soon as possible.



Please review and comment.

Abstract:

As OTN network capabilities continue to evolve, there is an increased  need to support GMPLS control for the same. [RFC4328] introduced GMPLS signaling extensions for supporting early version of G.709 [G.709-v1].The basic routing considerations from signaling perspective is also specified in [RFC4328].

The recent revision of ITU-T Recommendation G.709 [G.709-v3] and[GSUP.43] have introduced new ODU containers (both fixed and flexible) and additional ODU multiplexing capabilities, enabling support for optimal service aggregation.

This document extends [RFC4328] to provide GMPLS signaling support for the new OTN capabilities defined in [G.709-v3] and [GSUP.43]. The signaling extensions described in this document caters to ODU layer switching only. Optical Channel Layer switching considerations in [RFC4328] are not modified in this document.



Thanks

Authors



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