Liaison statement
Liaison to IETF on proposed Working Group on L2SM

State Posted
Posted Date 2016-10-31
From Group MEF
From Contact Raghu Ranganathan
To Groups IESG, OPS
To Contacts Benoit Claise
Joel Jaeggli
Response Contact
Purpose For action
Deadline 2017-01-23 Action Needed
Attachments L00254_001_2016Q4-Liaison-IETF-L2SMwg_Ranganath
Liaisons referring to this one Response to your liaison dated 31st October 2016
MEF Forum noticed the announcement of a proposed new L2SM Working Group in IETF ( 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

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 ( 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 ( focuses on Ethernet Virtual Connection (EVC) based Ethernet Services offered by a Service Provider (SP) to a Subscriber.
  - MEF 26.2 Specification ( 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 ( 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 ( defines a reference architecture that describes the functional management entities needed to support LSO, and the Management Interface Reference Points between
 - 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: for-mef-services-attachment-1.pdf
          - Nov 2015: (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

MEF’s liaison partners may access all MEF approved drafts as follows:
Username: mef
Password: M3F3030
The MEF meets next in Los Angeles, CA, USA on Jan 23-26, 2016.

Attach: mef-service-yang.tar.gz