Subject: [PWE3] draft-ietf-pwe3-vccv-impl-survey-results - AD review

From: Stewart Bryant <[email-masked]>
Date: Mon, 30 Apr 2012 20:43:11 +0100

PWE3 Chairs:

Here are my AD review comments on this draft

Please look for ">" in the first column.

- Stewart

=====

>  You present a lot of data, but there there is no conclusion.
>  I think that you really need to present the WG consensus conclusion
>  of the data section my section and the WG consensus conclusion of
>  the results and a whole and any recommended action.

====

  The Pseudowire (PW)&  Virtual Circuit Connectivity Verification (VCCV)
                      Implementation Survey Results
               draft-ietf-pwe3-vccv-impl-survey-results-00

Abstract

    Most Pseudowire Emulation Edge-to-Edge (PWE3) encapsulations mandate
    the use of the Control Word (CW) in order to better emulate the
    services for which the encapsulations have been defined.

>  Actually it's more fundamental than "better emulate" they carry
>  info fundamental to the emmulation.

======

1.  Introduction

    The IETF has defined many encapsulations of various layer 1 and layer
    2 service-specific PDUs and circuit data.

>  Surely this is the IETF PWE3 WG?
>  Aren't they also PW encaps?
>  There are many non PWE3 L2 encaps that have been defined.

Within these
    encapsulations, there are often several modes of encapsulation which
    have differing requirements in order to fully emulate the service.

  As such, the use of the PWE3 Control Word is mandated in many of the
    encapsulations, but not all.

>  The second sentence does not follow from the first

This can present interoperability
    issues related to A) Control Word use and B) VCCV Control Channel
    negotiation in mixed implementation environments.

>  and then this does not logically follow.
>  VCCV needs to be expanded and a ref provided

  The encapsulations and modes for which the Control Word is currently
  optional are:

    o  Ethernet Tagged Mode

    o  Ethernet Raw Mode

    o  PPP

    o  HDLC

    o  Frame Relay Port Mode

    o  ATM (N:1 Cell Mode)

>  You need a ref for each of the above

  [RFC5085] defines three Control Channel types for MPLS PW's: Type 1,

>  You will get a ref vs name IESG comment with the above.
>  You mean "VCCV [RFC5085]....."

    using the Pseudowire Control Word, Type 2, using the Router Alert
    Label, and Type 3, using TTL Expiration (e.g.  MPLS PW Label with TTL
    == 1).  While Type 2 (RA Label) is indicated as being "the preferred

>  Is RA a well known abbreviation?

====

  1.1.  PW/VCCV Survey Overview

    Per the direction of the PWE3 Working Group chairs, a survey was
    created to sample the nature of implementations of Pseudowires, with
    specific emphasis on Control Word usage, and VCCV, with emphasis on
    Control Channel and Control Type usage.  The survey consisted of a
    series of questions based on direction of the WG chairs and the
    survey opened to the public on November 4, 2010.  The URL for the
    survey (now closed) was http://www.surveymonkey.com/pwe3/.  The
    survey ran from November 4, 2010 until February 25, 2011.

>  A statement of fact that is currently unverifiable since the URL
>  is no longer valid.

  1.2.  PW/VCCV Survey Form

    The PW/VCCV Implementation Survey requested the following information
    about user implementations:

    - Responding Organziation.  No provisions were made for anonymity.
    All responses required a valid email address in order to validate the
    survey response.

    - Of the various encapsulations (and options therein) known at the
    time, including the WG draft for Fiber Channel), which were
    implemented b the respondent.  These included:

>  You need to provide refs for each of the PWs that you talk about
>  I know it's too late for the responders, but the for the future reader
>  it needs to be provided as a note somewhere.
>  Also with LSP ping and ICMP Ping - need a ref.

    o  Ethernet Tagged Mode - RFC 4448

    o  Ethernet Raw Mode - RFC 4448

    o  SAToP - RFC 4553

    o  PPP - RFC 4618

    o  HDLC - RFC 4618

    o  Frame Relay (Port Mode) - RFC 4619

    o  Frame Relay (1:1 Mode) - RFC 4619

    o  ATM (N:1 Mode) - RFC 4717

    o  ATM (1:1 Mode) - RFC 4717

    o  ATM (AAL5 SDU Mode) - RFC 4717

    o  ATM (AAL5 PDU Mode) - RFC 4717

    o  CEP - RFC 4842

    o  CESoPSN - RFC 5086

    o  TDMoIP - RFC 5087

    o  Fiber Channel (Port Mode) - draft-ietf-pwe3-fc-encap

    - Approximately how many Pseudowires of each type were deployed.
    Respondents could list a number, or for the sake of privacy, could
    just respond "In-Use" instead.

    - For each encapsulation listed above, the respondent could indicated
    which Control Channel was in use.  The options listed were:

    o  Control Word (Type 1)

    o  Router Alert Label (Type 2)

    o  TTL Expiry (Type 3)

    - For each encapsulation listed above, the respondent could indicate
    which Connectivity Verification types were in use.  The options were:

    o  ICMP Ping

    o  LSP Ping

    - For each encapsulation type for which the use of the Control Word
    is optional, the respondents could indicated the encaps for which
    Control Word was supported by the equipment used and whether it was
    in use in the network.  The encaps listed were:

    o  Ethernet (Tagged Mode)

    o  Ethernet (Raw Mode)

    o  PPP

    o  HDLC

    o  Frame Relay (Port Mode)

    o  ATM (N:1 Cell Mode)

    - Finally, a freeform entry was provided for the respondent to
    provide feedback regarding PW and VCCV deployments, VCCV
    interoperability challenges, the survey or any network/vendor details
    they wished to share.

========

2.  Survey Results

2.1.  Respondents

    The following companies participated in the PW/VCCV Implementation
    Survey.  The data provided has been aggregated.  No specific
    company's reponse will be detailed herein.

>  To preserve anonymity you need to make sure there is on order correlation
>  (and state that), and it would be nice to have the following in alphabetical
>  order

    o  Time Warner Cable

    o  Bright House Networks

    o  Tinet

    o  AboveNet

    o  Telecom New Zealand

    o  Cox Communications

    o  MTN South Africa

    o  Wipro Technologies

    o  Verizon

    o  AMS-IX

    o  Superonline

    o  Deutsche Telekom AG

    o  Internet Solution

    o  Easynet Global Services

    o  Telstra Corporation

    o  OJSC MegaFon

    o  France Telecom Orange

>  How did these operators know about this survey
>  Did any vendors reply, if so what action did you take?

=====

    4.  PW VCCV is very useful tool for finding faults in each PW
        channel.  Without this we can not find fault on a PW channel.  PW
        VCCV using BFD is another better option.  Introperbility
        challences are with Ethernet OAM mechanism.

>  Given the sensitivity please clarify if you mean Eth OAM, or
>  OAM for Eth PWs.

====

3.  Security Considerations

    As this document is a report of the PW/VCCV User Implementation
    Survey results, no security considerations are introduced.

>  SCs should include the precautions you took to ensure the validity
>  of the sample and the data.