Liaison statement
Liaison to IETF on proposed Working Group on L2SM

MEF Forum noticed the announcement of a proposed new L2SM Working Group in IETF
(https://datatracker.ietf.org/wg/l2sm/charter/). In particular, we see the
following in the proposed charter:

 - "The model can be used for communication between customers and network
 operators, and              to provide input to automated control
      and configuration applications."
 -"Instead, the L2VPN customer service model contains the characteristics of
 the service as discussed between the operators and their
    customers."

We include the following relevant information on MEF published and ongoing work
for your consideration - note in particular that MEF is already working on Yang
modules for MEF services:

1) MEF Service Model & Attributes (Published Specifications)
  - MEF 10.3 Specification
  (https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_10.3.pdf)
  describes Ethernet Service
attributes for services provided to the Subscriber (end user) by the Service
Provider. The Ethernet Services are modeled from the point of view of the
Subscriber’s equipment referred to as the Customer Edge (CE) that is used to
access the service.
        - Note-1: MEF uses 'Subscriber' to refer to user (or Customer) of
        Ethernet Services
       -  Note-2: MEF uses 'CE' to refer to Customer Edge for Equipment on the
       Subscriber side of UNI (i.e., owned by Subscriber)
  - MEF 6.2 Specification
  (https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_6.2.pdf) focuses
  on Ethernet Virtual Connection (EVC) based Ethernet Services offered by a
  Service Provider (SP) to a Subscriber. - MEF 26.2 Specification
  (https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_26.2.pdf)
  provides the models and framework for interconnecting multiple Carrier
  Ethernet Networks (CENs), and the service attributes for services provided by
  one Operator to another or to a Service Provider. - MEF 51 Specification
  (http://www.mef.net/Assets/Technical_Specifications/PDF/MEF_51.pdf) focuses
  on Operator Virtual Connection (OVC) based Ethernet Services offered by an
  Operator where at least one OVC Endpoint is at an ENNI.

2) MEF Service Information Model (Ongoing Project)
  - MEF has an ongoing project for MEF Carrier Ethernet Services Management
  Information Model and has draft approved for final
Letter Ballot (i.e., if successful will be published as MEF 7.3 in January
2017).
  - The latest Approved Draft version is available at the liaison login link
  provided below.

3) MEF Lifecycle Service Orchestration Reference Architecture (Published
Specification)
  - MEF 55 Specification
  (https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_55.pdf) defines
  a reference architecture that describes the functional management entities
  needed to support LSO, and the Management Interface Reference Points between
them.
 - MEF's work on Service Information & Data Models can be applicable for the
 following interfaces supported by the Service
Orchestration Function (SOF) as shown in Figure 2 of MEF 55 and described in
Section 9.3 of MEF 55:
       - ALLEGRO (CUS:SOF): The Management Interface Reference Point that
       allows Customer Application Coordinator
supervision and control of dynamic service behavior (see Section 8.2.3) of the
LSO service capabilities under its purview through interactions with the
Service Orchestration Functionality.
       - LEGATO (BUS:SOF): The Management Interface Reference Point between the
       Business Applications and the Service
Orchestration Functionality needed to allow management and operations
interactions supporting LSO connectivity services.
       - INTERLUDE (SOF:SOF): The Management Interface Reference Point that
       provides for the coordination of a portion of LSO
services within the partner domain that are managed by a Service Provider’s
Service Orchestration Functionality within the bounds and policies defined for
the service.

4) MEF YANG Modules for MEF Services (Ongoing Project)
  - Please see our previous Liaison to IETF
          -  Jan 2015:
          https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2015-02-04-mef-the-ietf-liaison-about-new-project-on-yangmodules-
          for-mef-services-attachment-1.pdf - Nov 2015:
          https://datatracker.ietf.org/liaison/1439/ (includes attachment of
          the re-scope)
  - Draft YANG Modules are currently being updated to address member comments;
  the latest versions are attached and MEF will share the final versions once
  they are completed.

Additionally, MEF would like clarification on the proposed charter. For
example, the text in charter includes - "The working group will attempt to
derive a single data model that includes support for point-to-point Virtual
Private Wire Services (VPWS), multipoint Virtual Private LAN services (VPLS)
that use Pseudowires signaled using the Label Distribution Protocol (LDP) and
the Border Gateway Protocol (BGP) as described in RFC4761 and RFC6624, and
Ethernet VPNs specified in RFC 7432." Is the focus of L2SM about the internal
network technologies and implementations as opposed to "characteristics of the
service as discussed between the operators and their customers"?

Assuming the focus is on the latter, i.e., "characteristics of the service as
discussed between the operators and their customers", we would like to suggest
that, if the working group is approved, IETF proceeds by augmenting the MEF
Yang modules instead of duplicating the work that has already been done in MEF.

MEF looks forward to collaborating with IETF to provide the industry with a
single standard Ethernet Service model and related YANG Modules.

MEF’s liaison partners may access all MEF approved drafts as follows:

https://mef.net/liaison-login
Username: mef
Password: M3F3030
The MEF meets next in Los Angeles, CA, USA on Jan 23-26, 2016.

Attach: mef-service-yang.tar.gz