Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Leeyoung <leeyoung@huawei.com> Wed, 10 October 2018 15:20 UTC

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From: Leeyoung <leeyoung@huawei.com>
To: Gert Grammel <ggrammel@juniper.net>, "ccamp@ietf.org" <ccamp@ietf.org>
Thread-Topic: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt
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Date: Wed, 10 Oct 2018 15:20:39 +0000
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Subject: Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt
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Hi Gert,

The direction is to keep WSON as is and would add explicit property of Modulation/FEC types, etc. in the augmented impairment model.

For WSON-topology, the format is series of “string”.  We would keep this format in  WSON-model. What do you need to see more for this case?

typedef operational-mode {
    type string;
    description
      "Vendor-specific mode that guarantees interoperability.
       It must be an string with the following format:
       B-DScW-ytz(v) where all these attributes are conformant
       to the ITU-T recomendation";
    reference "ITU-T G.698.2 (11/2009) Section 5.3";
  }

Now, when you want impairment model augmented from WSON, we would like to use the TTP to describe explicitly each component. Let us know what do you want to see more from the following?

augment /nw:networks/nw:network/nw:node/tet:te/tet:tunnel-termination-point:
       +--ro available-modulation*   identityref
       +--ro modulation-enabled?     boolean
       +--ro modulation-type?        identityref
       +--ro available-FEC*          identityref
       +--ro FEC-enabled?            boolean
       +--ro FEC-type?               identityref
       +--ro FEC-code-rate?          decimal64
       +--ro FEC-threshold?          decimal64

Thanks.
Young
From: Gert Grammel [mailto:ggrammel@juniper.net]
Sent: Wednesday, October 10, 2018 10:07 AM
To: Leeyoung <leeyoung@huawei.com>; ccamp@ietf.org
Cc: Dieter Beller <Dieter.Beller@nokia.com>; Zhenghaomian (Zhenghaomian, Optical &Microwave Technology Research Dept) <zhenghaomian@huawei.com>
Subject: Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Young,

Unfortunately I wasn’t able to properly compile your last email. What do you have in mind with “THAT”?
                                <snip> Yes, THAT is the direction we are taking with the impairment model. <snip>


  1.  If “that” means using G.698.2 application codes, the draft would need to be changed substantially
  2.  If “that” means draft-lee-ccamp-wson-impairment-yang-00 as-is, it would question the use of application codes and discussion in the WG.

Thanks

Gert

From: 'Leeyoung' <leeyoung@huawei.com<mailto:leeyoung@huawei.com>>
Date: Wednesday, October 10, 2018 at 16:51
To: Gert Grammel <ggrammel@juniper.net<mailto:ggrammel@juniper.net>>, CCAMP <ccamp@ietf.org<mailto:ccamp@ietf.org>>
Cc: Dieter Beller <Dieter.Beller@nokia.com<mailto:Dieter.Beller@nokia.com>>, "Zhenghaomian (Zhenghaomian, Optical &Microwave Technology Research Dept)" <zhenghaomian@huawei.com<mailto:zhenghaomian@huawei.com>>
Subject: RE: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Hi Gert,

Yes, that is the direction we are taking with the impairment model.

Thanks.
Young

From: Gert Grammel [mailto:ggrammel@juniper.net]
Sent: Wednesday, October 10, 2018 9:42 AM
To: Leeyoung <leeyoung@huawei.com<mailto:leeyoung@huawei.com>>; ccamp@ietf.org<mailto:ccamp@ietf.org>
Cc: Dieter Beller <Dieter.Beller@nokia.com<mailto:Dieter.Beller@nokia.com>>; Zhenghaomian (Zhenghaomian, Optical &Microwave Technology Research Dept) <zhenghaomian@huawei.com<mailto:zhenghaomian@huawei.com>>
Subject: Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Yang,

I was referring to
augment /nw:networks/nw:network/nw:node/tet:te/tet:tunnel-termination-point:
       +--ro available-modulation*   identityref
       +--ro modulation-enabled?     boolean
       +--ro modulation-type?        identityref
       +--ro available-FEC*          identityref
       +--ro FEC-enabled?            boolean
       +--ro FEC-type?               identityref
       +--ro FEC-code-rate?          decimal64
       +--ro FEC-threshold?          decimal64

For example:
The modulation is part of the application code (from the actual G.698.2 a bit shortened for readability):
The application code notation is constructed as follows: DScW-ytz(v)
where,
D is the indicator of DWDM applications.
S indicates options of maximum spectral excursion such as:
·       –  N indicating narrow spectral excursion.
·       –  W indicating wide spectral excursion. c is the channel spacing in GHz.
W indicates the black link dispersion compensation regime as follows:
·       –  C indicating that the chromatic dispersion values are appropriate to a black link that is
dispersion compensated.
·       –  U indicating that the chromatic dispersion values are appropriate to a black link that is dispersion uncompensated.
y indicates the highest class of optical tributary signal supported:
o   –  1 indicating NRZ 2.5G.
o   –  2 indicating NRZ 10G.
t is a letter indicating the configuration supported by the application code. In the current version of this Recommendation, the only value used is:
– A indicating that the black link may contain optical amplifiers. z indicates the fibre types, as follows:
·       –  2 indicating ITU-T G.652 fibre.
·       –  3 indicating ITU-T G.653 fibre.
·       –  5 indicating ITU-T G.655 fibre.
v indicates the operating wavelength range in terms of spectral bands (see [b-ITU-T G-Sup.39]):
If more than one spectral band is used, then v becomes the band letters separated by "+", e.g., for an application requiring the use of both of the C and L bands, v would be "C+L".
For some application codes, a suffix is added to the end of the code. The only suffix currently defined is:
– F to indicate that this application requires FEC bytes as specified in [ITU-T G.709] to be transmitted.

So under the assumption the application code is defined for the tunnel termination point:
augment /nw:networks/nw:network/nw:node/tet:te/tet:tunnel-termination-point:
       +--ro available-modulation*   identityref --> Parameter y
       +--ro modulation-enabled?     Boolean --> the code defines only one modulation, not enabled/disabled
       +--ro modulation-type?        Identityref --> parameter y
       +--ro available-FEC*          identityref --> parameter F is a Boolean
       +--ro FEC-enabled?            Boolean  --> enabled/disabled would result in two different application codes (with and without tailing F)
       +--ro FEC-type?               Identityref --> F
       +--ro FEC-code-rate?          decimal64 --> since F is defined, this one is defined too
       +--ro FEC-threshold?          decimal64 --> since F is defined, this one is defined too


Best

Gert


From: 'Leeyoung' <leeyoung@huawei.com<mailto:leeyoung@huawei.com>>
Date: Wednesday, October 10, 2018 at 16:21
To: Gert Grammel <ggrammel@juniper.net<mailto:ggrammel@juniper.net>>, CCAMP <ccamp@ietf.org<mailto:ccamp@ietf.org>>
Cc: Dieter Beller <Dieter.Beller@nokia.com<mailto:Dieter.Beller@nokia.com>>, "Zhenghaomian (Zhenghaomian, Optical &Microwave Technology Research Dept)" <zhenghaomian@huawei.com<mailto:zhenghaomian@huawei.com>>
Subject: RE: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Hi Gert,

In the current WSON model, we have the following:

augment /nw:networks/nw:network/nw:node/tet:te/tet:tunnel-termination-point:
    +--rw supported-operational-modes*    te-wson-types:operational-mode
    +--rw configured-operational-modes?   te-wson-types:operational-mode
    +--rw supported-fec-types*            identityref
    +--rw supported-termination-types*    identityref
    +--rw supports-bit-stuffing?          boolean

So we are describing application codes in the TTP. Is this what you meant to describe application code in the Termination Point?

Thanks.
Young

From: Gert Grammel [mailto:ggrammel@juniper.net]
Sent: Wednesday, October 10, 2018 3:54 AM
To: ccamp@ietf.org<mailto:ccamp@ietf.org>
Cc: Dieter Beller <Dieter.Beller@nokia.com<mailto:Dieter.Beller@nokia.com>>; Leeyoung <leeyoung@huawei.com<mailto:leeyoung@huawei.com>>; Zhenghaomian (Zhenghaomian, Optical &Microwave Technology Research Dept) <zhenghaomian@huawei.com<mailto:zhenghaomian@huawei.com>>
Subject: Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt


The draft triggered a question about the approach we are using in ccamp to address WSON going forward. In the past, the group aimed for alignment with ITU-T and using application codes to describe optical capabilities. Is this still the way forward?
If so, my expectation would be to find application codes as description of termination points.
If the view changed, it should be spelled out.

Gert


From: CCAMP <ccamp-bounces@ietf.org<mailto:ccamp-bounces@ietf.org>> on behalf of Dieter Beller <Dieter.Beller@nokia.com<mailto:Dieter.Beller@nokia.com>>
Organization: Nokia
Date: Thursday, September 27, 2018 at 11:07
To: 'Leeyoung' <leeyoung@huawei.com<mailto:leeyoung@huawei.com>>, Zhenghaomian <zhenghaomian@huawei.com<mailto:zhenghaomian@huawei.com>>
Cc: CCAMP <ccamp@ietf.org<mailto:ccamp@ietf.org>>
Subject: Re: [CCAMP] I-D Action: draft-lee-ccamp-wson-impairment-yang-00.txt

Hi Young and Haomian,

I had a look at draft-lee-ccamp-wson-impairment-yang-00, which you submitted a few weeks ago and I have the following concerns:

The abstract and introduction states:

Abstract



   This document provides a YANG data model for the impairment-aware TE

   topology in wavelength switched optical networks (WSONs).


1. Introduction



   ...



   This document provides a YANG data model for the impairment-aware

   Traffic Engineering (TE) topology in wavelength switched optical

   networks (WSONs). The YANG model described in this document is a

   WSON technology-specific Yang model based on the information model

   developed in [RFC7446<https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc7446&d=DwMDaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Sf-T94Aod4TTEURQzTXYYw-Q-H8PyeOsweqqcNyVIcU&m=zk3zS00lx60_LBxIKggxhMkHsPCBJ4biAFdpDYpeTGA&s=t3EVJKIBbfBziQCv67C_SIGqCsL1lLO5QfzEzD1wC0Y&e=>] and the two encoding documents [RFC7581<https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc7581&d=DwMDaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Sf-T94Aod4TTEURQzTXYYw-Q-H8PyeOsweqqcNyVIcU&m=zk3zS00lx60_LBxIKggxhMkHsPCBJ4biAFdpDYpeTGA&s=S4OUJ2my7xLw9DxcGX9NUyph3GbY44XOtQud1wwYp-A&e=>] and

   [RFC7579<https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc7579&d=DwMDaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Sf-T94Aod4TTEURQzTXYYw-Q-H8PyeOsweqqcNyVIcU&m=zk3zS00lx60_LBxIKggxhMkHsPCBJ4biAFdpDYpeTGA&s=V6LYiY4JVdT0RvJb6BoDJ0MWyLwIBz-nlotLCl8iNWk&e=>] that developed protocol independent encodings based on

   [RFC7446<https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_html_rfc7446&d=DwMDaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Sf-T94Aod4TTEURQzTXYYw-Q-H8PyeOsweqqcNyVIcU&m=zk3zS00lx60_LBxIKggxhMkHsPCBJ4biAFdpDYpeTGA&s=t3EVJKIBbfBziQCv67C_SIGqCsL1lLO5QfzEzD1wC0Y&e=>].



Based on this scope, I was expecting that this I-D provides te-link augmentations for WSON networks.
Examples of WSON specific te-link attributes are fiber type, spectrum availability, chromatic dispersion, PMD, PDL, OSNR contribution (if the link includes ILAs) just to list a few.

However, the only te-link augmentation is:

     augment /nw:networks/nw:network/nt:link/tet:te/tet:te-link-attributes:

       +--ro power?   int32

It is also reasonable to define WSON augmentations for termination points representing the line side of optical transponders as they can be considered as topological elements
even if these attributes are not representing optical impairments!:

     augment /nw:networks/nw:network/nw:node/tet:te/tet:tunnel-termination-point:

       +--ro available-modulation*   identityref

       +--ro modulation-enabled?     boolean

       +--ro modulation-type?        identityref

       +--ro available-FEC*          identityref

       +--ro FEC-enabled?            boolean

       +--ro FEC-type?               identityref

       +--ro FEC-code-rate?          decimal64

       +--ro FEC-threshold?          decimal64


I don't understand why all the OT attributes are defined as ro attributes. State of the art OTs typically provide multiple operational modes. Hence, these attributes should
be defined as rw attributes.


All other augmentations are defined for paths (te-tunnels) or termination points, which is a bit strange! Here are two examples:

     augment /nw:networks/nw:network/nt:link/tet:te/tet:te-link-

   attributes/tet:underlay/tet:primary-path/tet:path-

   element/tet:type/tet:label/tet:label-hop/tet:te-label/tet:technology:

       +--:(wson-imp-topo)

          +--rw (grid-type)?

          |  +--:(dwdm)

          |  |  +--ro channel-freq?         decimal64

          |  +--:(cwdm)

          |     +--ro channel-wavelength?   uint32

          +--ro bit-rate?             decimal64

          +--ro BER?                  decimal64

          +--ro pmd?                  decimal64

          +--ro cd?                   decimal64

          +--ro osnr?                 decimal64

          +--ro q-factor?             decimal64

channel-freq/channel-wavelength, bit-rate, BER are definitively service (te-tunnel) attributes and do not represent optical impairments for a WSON network topology.
For pmd, cd, and q-factor (definition?), it looks like these are attributes for all the links along the path. Why are these impairments defined for a path and are not te-link
augmentations?

I was expecting that this draft defines optical impairments for the topological entities in a WSON network where optical impairments matter. Could you please clarify.


Thanks,
Dieter


On 01.09.2018 05:42, internet-drafts@ietf.org<mailto:internet-drafts@ietf.org> wrote:

A New Internet-Draft is available from the on-line Internet-Drafts directories.





        Title           : A Yang Data Model for Impairment-Aware WSON Optical Networks

        Authors         : Young Lee

                          Haomian Zheng

  Filename        : draft-lee-ccamp-wson-impairment-yang-00.txt

  Pages           : 18

  Date            : 2018-08-31



Abstract:

   This document provides a YANG data model for the impairment-aware TE

   topology in wavelength switched optical networks (WSONs).









The IETF datatracker status page for this draft is:

https://datatracker.ietf.org/doc/draft-lee-ccamp-wson-impairment-yang/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_doc_draft-2Dlee-2Dccamp-2Dwson-2Dimpairment-2Dyang_&d=DwMDaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Sf-T94Aod4TTEURQzTXYYw-Q-H8PyeOsweqqcNyVIcU&m=zk3zS00lx60_LBxIKggxhMkHsPCBJ4biAFdpDYpeTGA&s=uI9XVdKyAYxfJxgBNbJzFb7PcL4ucbR7pQ3vwpUtFww&e=>



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