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The Pseudowire (PW) and Virtual Circuit Connectivity Verification (VCCV) Implementation Survey Results
RFC 7079

Document Type RFC - Informational (November 2013)
Authors Nick Del Regno , Andrew G. Malis
Last updated 2015-10-14
RFC stream Internet Engineering Task Force (IETF)
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IESG Responsible AD Stewart Bryant
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RFC 7079
Internet Engineering Task Force (IETF)                 N. Del Regno, Ed.
Request for Comments: 7079                  Verizon Communications, Inc.
Category: Informational                                    A. Malis, Ed.
ISSN: 2070-1721                                               Consultant
                                                           November 2013

The Pseudowire (PW) and Virtual Circuit Connectivity Verification (VCCV)
                     Implementation Survey Results

Abstract

   The IETF Pseudowire Emulation Edge-to-Edge (PWE3) working group has
   defined many encapsulations of various layer 1 and layer 2 service-
   specific PDUs and circuit data.  In most of these encapsulations, use
   of the Pseudowire (PW) Control Word is required.  However, there are
   several encapsulations for which the Control Word is optional, and
   this optionality has been seen in practice to possibly introduce
   interoperability concerns between multiple implementations of those
   encapsulations.  This survey of the Pseudowire / Virtual Circuit
   Connectivity Verification (VCCV) user community was conducted to
   determine implementation trends and the possibility of always
   mandating the Control Word.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7079.

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

Table of Contents

   1. Introduction ....................................................4
      1.1. PW/VCCV Survey Overview ....................................5
      1.2. PW/VCCV Survey Form ........................................5
      1.3. PW/VCCV Survey Highlights ..................................7
   2. Survey Results ..................................................8
      2.1. Summary of Results .........................................8
      2.2. Respondents ................................................8
      2.3. Pseudowire Encapsulations Implemented ......................9
      2.4. Number of Pseudowires Deployed ............................10
      2.5. VCCV Control Channel in Use ...............................11
      2.6. VCCV Connectivity Verification Types in Use ...............14
      2.7. Control Word Support for Encapsulations for Which
           CW Is Optional ............................................16
      2.8. Open-Ended Question .......................................17
   3. Security Considerations ........................................18
   4. Acknowledgements ...............................................18
   5. Informative References .........................................19
   Appendix A. Survey Responses ......................................20
     A.1. Respondent 1 ...............................................20
     A.2. Respondent 2 ...............................................21
     A.3. Respondent 3 ...............................................22
     A.4. Respondent 4 ...............................................23
     A.5. Respondent 5 ...............................................24
     A.6. Respondent 6 ...............................................25
     A.7. Respondent 7 ...............................................27
     A.8. Respondent 8 ...............................................28
     A.9. Respondent 9 ...............................................29
     A.10. Respondent 10 .............................................30
     A.11. Respondent 11 .............................................31
     A.12. Respondent 12 .............................................32
     A.13. Respondent 13 .............................................33
     A.14. Respondent 14 .............................................35
     A.15. Respondent 15 .............................................36
     A.16. Respondent 16 .............................................38
     A.17. Respondent 17 .............................................39

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

1.  Introduction

   Most Pseudowire Emulation Edge-to-Edge (PWE3) encapsulations mandate
   the use of the Control Word (CW) to carry information essential to
   the emulation, to inhibit Equal-Cost Multipath (ECMP) behavior, and
   to discriminate Operations, Administration, and Maintenance (OAM)
   from Pseudowire (PW) packets.  However, some encapsulations treat the
   Control Word as optional.  As a result, implementations of the CW,
   for encapsulations for which it is optional, vary by equipment
   manufacturer, equipment model, and service provider network.
   Similarly, Virtual Circuit Connectivity Verification (VCCV) supports
   three Control Channel (CC) types and multiple Connectivity
   Verification (CV) types.  This flexibility has led to reports of
   interoperability issues within deployed networks and associated
   documents to attempt to remedy the situation.

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

   o  Ethernet Tagged Mode [RFC4448]

   o  Ethernet Raw Mode [RFC4448]

   o  Point-to-Point Protocol (PPP) [RFC4618]

   o  High-Level Data Link Control (HDLC) [RFC4618]

   o  Frame Relay Port Mode [RFC4618]

   o  ATM (N:1 Cell Mode) [RFC4717]

   Virtual Circuit Connectivity Verification (VCCV) [RFC5085] defines
   three Control Channel types for MPLS PWs: Type 1, using the PW
   Control Word; Type 2, using the Router Alert (RA) Label; and Type 3,
   using Time to Live (TTL) Expiration (e.g., MPLS PW Label with TTL ==
   1).  While Type 2 (RA Label) is indicated as being "the preferred
   mode of VCCV operation when the Control Word is not present", RFC
   5085 does not indicate a mandatory Control Channel to ensure
   interoperable implementations.  The closest it comes to mandating a
   control channel is the requirement to support Type 1 (Control Word)
   whenever the CW is present.  As such, the three options yield seven
   implementation permutations (assuming you have to support at least
   one Control Channel type to provide VCCV).  Due to these
   permutations, interoperability challenges have been identified by
   several VCCV users.

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

   In order to assess the best approach to address the observed
   interoperability issues, the PWE3 working group decided to solicit
   feedback from the PW and VCCV user community regarding
   implementation.  This document presents the survey questionnaire and
   the information returned by those in the user community who
   participated.

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 PWs, 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 survey was conducted using
   the SurveyMonkey tool, http://www.surveymonkey.com.  The survey ran
   from November 4, 2010 until February 25, 2011 and was repeatedly
   publicized on the PWE3 email list over that period.

   The editors took precautions to ensure the validity of the sample and
   the data.  Specifically, only responses with recognizable non-vendor
   company-affiliated email addresses were accepted.  Unrecognizable or
   personal email addresses would have been contacted to determine their
   validity, but none were received.  Only one response was received
   from each responding company.  If multiple responses from a company
   had been received, they would have been contacted to determine
   whether the responses were duplicative or additive.  This, however,
   did not occur.

1.2.  PW/VCCV Survey Form

   The PW/VCCV Implementation Survey requested the following information
   about user implementations (the lists of implementation choices were
   taken verbatim from the survey):

   -  Responding Organization.  No provisions were made for anonymous
      responses, as all responses required a valid email address in
      order to validate the survey response.  However, the results
      herein are reported anonymously, except for an alphabetic list of
      participating organizations in Section 2.2.

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   -  Of the various encapsulations (and options therein) known at the
      time, including the WG document, "Encapsulation Methods for
      Transport of Fibre Channel" (now [RFC6307]), which were
      implemented by the respondent.  These included:

      o  Ethernet Tagged Mode - RFC 4448

      o  Ethernet Raw Mode - RFC 4448

      o  Structure-Agnostic Time Division Multiplexing (TDM) over Packet
         (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 Service Data Unit (SDU) Mode) - RFC 4717

      o  ATM (AAL5 PDU Mode) - RFC 4717

      o  Circuit Emulation over Packet (CEP) - RFC 4842

      o  Circuit Emulation Service over Packet Switched Network
         (CESoPSN) - RFC 5086

      o  Time Division Multiplexing over IP (TDMoIP) - RFC 5087

      o  Fiber Channel (Port Mode) - "Encapsulation Methods for
         Transport of Fibre Channel" (now RFC 6307)

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

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   -  For each encapsulation listed above, the respondent could indicate
      which Control Channel [RFC5085] was in use.  (See Section 1 for a
      discussion of these Control Channels.)  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 [RFC5085] were in use.  The
      options were:

      o  Internet Control Message Protocol (ICMP) Ping

      o  Label Switched Path (LSP) Ping

   -  For each encapsulation type for which the Control Word is
      optional, the respondents could indicate the encapsulation(s) for
      which Control Word was supported by the equipment vendor, and
      whether the CW was also in use in the network.  The encapsulations
      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 free-form entry was provided for the respondent to
      provide feedback regarding PW and VCCV deployments, VCCV
      interoperability challenges, or the survey or any other network/
      vendor details they wished to share.

1.3.  PW/VCCV Survey Highlights

   There were seventeen responses to the survey that met the validity
   requirements in Section 1.1.  The responding companies are listed
   below in Section 2.2.

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2.  Survey Results

2.1.  Summary of Results

   Prior to this survey, there was considerable speculation about
   whether the Control Word could always be mandated, with several
   proposals to do so.  However, the survey showed that there was
   considerable deployment of PWs that did not use the CW.  The
   publication of this survey serves as a reminder of the extent of PWs
   without the CW in use, and hence a reminder that the CW-less modes
   cannot be deprecated in the near future.

2.2.  Respondents

   The following companies, listed here alphabetically as received in
   the survey responses, participated in the PW/VCCV Implementation
   Survey.  Responses were only solicited from non-vendors (users and
   service providers), and no vendors responded (although if they had,
   their response would not have been included).  The data provided has
   been aggregated.  No specific company's response will be detailed
   herein.

   o  AboveNet

   o  AMS-IX

   o  Bright House Networks

   o  Cox Communications

   o  Deutsche Telekom AG

   o  Easynet Global Services

   o  France Telecom Orange

   o  Internet Solution

   o  MTN South Africa

   o  OJSC MegaFon

   o  Superonline

   o  Telecom New Zealand

   o  Telstra Corporation

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   o  Time Warner Cable

   o  Tinet

   o  Verizon

   o  Wipro Technologies

2.3.  Pseudowire Encapsulations Implemented

   The following request was made: "In your network in general, across
   all products, please indicate which pseudowire encapsulations your
   company has implemented."  Of all responses, the following list shows
   the percentage of responses for each encapsulation:

   o  Ethernet Tagged Mode - RFC 4448 = 76.5%

   o  Ethernet Raw Mode - RFC 4448 = 82.4%

   o  SAToP - RFC 4553 = 11.8%

   o  PPP - RFC 4618 = 11.8%

   o  HDLC - RFC 4618 = 5.9%

   o  Frame Relay (Port Mode) - RFC 4619 = 17.6%

   o  Frame Relay (1:1 Mode) - RFC 4619 = 41.2%

   o  ATM (N:1 Mode) - RFC 4717 = 5.9%

   o  ATM (1:1 Mode) - RFC 4717 = 17.6%

   o  ATM (AAL5 SDU Mode) - RFC 4717 = 5.9%

   o  ATM (AAL5 PDU Mode) - RFC 4717 = 0.0%

   o  CEP - RFC 4842 = 0.0%

   o  CESoPSN - RFC 5086 = 11.8%

   o  TDMoIP - RFC 5087 = 11.8%

   o  Fiber Channel (Port Mode) - "Encapsulation Methods for Transport
      of Fibre Channel" (now RFC 6307) = 5.9%

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2.4.  Number of Pseudowires Deployed

   The following question was asked: "Approximately how many pseudowires
   are deployed of each encapsulation type.  Note, this should be the
   number of pseudowires in service, carrying traffic, or pre-positioned
   to do so."  The following list shows the number of pseudowires in use
   for each encapsulation:

   o  Ethernet Tagged Mode = 93,861

   o  Ethernet Raw Mode = 94,231

   o  SAToP - RFC 4553 = 20,050

   o  PPP - RFC 4618 = 500

   o  HDLC - RFC 4618 = 0

   o  Frame Relay (Port Mode) - RFC 4619 = 5,002

   o  Frame Relay (1:1 Mode) - RFC 4619 = 50,959

   o  ATM (N:1 Mode) - RFC 4717 = 50,000

   o  ATM (1:1 Mode) - RFC 4717 = 70,103

   o  ATM (AAL5 SDU Mode) - RFC 4717 = 0

   o  ATM (AAL5 PDU Mode) - RFC 4717 = 0

   o  CEP - RFC 4842 = 0

   o  CESoPSN - RFC 5086 = 21,600

   o  TDMoIP - RFC 5087 = 20,000

   o  Fiber Channel (Port Mode) - "Encapsulation Methods for Transport
      of Fibre Channel" (now RFC 6307) = 0

   In the above responses (on several occasions), the response was in
   the form of "> XXXXX" where the response indicated a number greater
   than the one provided.  Where applicable, the number itself was used
   in the sums above.  For example, ">20K" and "20K+" yielded 20K.

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   Additionally, the following encapsulations were listed as "In-Use"
   with no quantity provided:

   o  Ethernet Raw Mode: 2 Responses

   o  ATM (AAL5 SDU Mode): 1 Response

   o  TDMoIP: 1 Response

2.5.  VCCV Control Channel in Use

   The following instructions were given: "Please indicate which VCCV
   Control Channel is used for each encapsulation type.  Understanding
   that users may have different networks with varying implementations,
   for your network in general, please select all which apply."  The
   numbers below indicate the number of responses.  The responses were:

   o  Ethernet Tagged Mode - RFC 4448

      *  Control Word (Type 1) = 7

      *  Router Alert Label (Type 2) = 3

      *  TTL Expiry (Type 3) = 3

   o  Ethernet Raw Mode - RFC 4448

      *  Control Word (Type 1) = 8

      *  Router Alert Label (Type 2) = 4

      *  TTL Expiry (Type 3) = 4

   o  SAToP - RFC 4553

      *  Control Word (Type 1) = 1

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  PPP - RFC 4618

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

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   o  HDLC - RFC 4618

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  Frame Relay (Port Mode) - RFC 4619

      *  Control Word (Type 1) = 1

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

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

      *  Control Word (Type 1) = 3

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 2

   o  ATM (N:1 Mode) - RFC 4717

      *  Control Word (Type 1) = 1

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  ATM (1:1 Mode) - RFC 4717

      *  Control Word (Type 1) = 1

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 1

   o  ATM (AAL5 SDU Mode) - RFC 4717

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 1

      *  TTL Expiry (Type 3) = 0

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   o  ATM (AAL5 PDU Mode) - RFC 4717

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  CEP - RFC 4842

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  CESoPSN - RFC 5086

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 1

   o  TDMoIP - RFC 5087

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

   o  Fiber Channel (Port Mode) - "Encapsulation Methods for Transport
      of Fibre Channel" (now RFC 6307)

      *  Control Word (Type 1) = 0

      *  Router Alert Label (Type 2) = 0

      *  TTL Expiry (Type 3) = 0

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

2.6.  VCCV Connectivity Verification Types in Use

   The following instructions were given: "Please indicate which VCCV
   Connectivity Verification types are used in your networks for each
   encapsulation type."  Note that Bidirectional Forwarding Detection
   (BFD) was not one of the choices.  The responses were as follows:

   o  Ethernet Tagged Mode - RFC 4448

      *  ICMP Ping = 5

      *  LSP Ping = 11

   o  Ethernet Raw Mode - RFC 4448

      *  ICMP Ping = 6

      *  LSP Ping = 11

   o  SAToP - RFC 4553

      *  ICMP Ping = 0

      *  LSP Ping = 2

   o  PPP - RFC 4618

      *  ICMP Ping = 0

      *  LSP Ping = 0

   o  HDLC - RFC 4618

      *  ICMP Ping = 0

      *  LSP Ping = 0

   o  Frame Relay (Port Mode) - RFC 4619

      *  ICMP Ping = 0

      *  LSP Ping = 1

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

      *  ICMP Ping = 2

      *  LSP Ping = 5

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   o  ATM (N:1 Mode) - RFC 4717

      *  ICMP Ping = 0

      *  LSP Ping = 1

   o  ATM (1:1 Mode) - RFC 4717

      *  ICMP Ping = 0

      *  LSP Ping = 3

   o  ATM (AAL5 SDU Mode) - RFC 4717

      *  ICMP Ping = 0

      *  LSP Ping = 1

   o  ATM (AAL5 PDU Mode) - RFC 4717

      *  ICMP Ping = 0

      *  LSP Ping = 0

   o  CEP - RFC 4842

      *  ICMP Ping = 0

      *  LSP Ping = 0

   o  CESoPSN - RFC 5086

      *  ICMP Ping = 0

      *  LSP Ping = 1

   o  TDMoIP - RFC 5087

      *  ICMP Ping = 0

      *  LSP Ping = 1

   o  Fiber Channel (Port Mode) - "Encapsulation Methods for Transport
      of Fibre Channel" (now RFC 6307)

      *  ICMP Ping = 0

      *  LSP Ping = 0

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2.7.  Control Word Support for Encapsulations for Which CW Is Optional

   The following instructions were given: "Please indicate your
   network's support of and use of the Control Word for encapsulations
   for which the Control Word is optional."  The responses were:

   o  Ethernet (Tagged Mode)

      *  Supported by Network/Equipment = 13

      *  Used in Network = 6

   o  Ethernet (Raw Mode)

      *  Supported by Network/Equipment = 14

      *  Used in Network = 7

   o  PPP

      *  Supported by Network/Equipment = 5

      *  Used in Network = 0

   o  HDLC

      *  Supported by Network/Equipment = 4

      *  Used in Network = 0

   o  Frame Relay (Port Mode)

      *  Supported by Network/Equipment = 3

      *  Used in Network = 1

   o  ATM (N:1 Cell Mode)

      *  Supported by Network/Equipment = 5

      *  Used in Network = 1

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2.8.  Open-Ended Question

   Space was provided for user feedback.  The following instructions
   were given: "Please use this space to provide any feedback regarding
   PW and VCCV deployments, VCCV interoperability challenges, this
   survey or any network/vendor details you wish to share."  Below are
   the responses, made anonymous.  The responses are otherwise provided
   here verbatim.

   1.  BFD VCCV Control Channel is not indicated in the survey (may be
       required for PW redundancy purpose)

   2.  Using CV is not required at the moment

   3.  COMPANY has deployed several MPLS network elements, from multiple
       vendors.  COMPANY is seeking a uniform implementation of VCCV
       Control Channel (CC) capabilities across its various vendor
       platforms.  This will provide COMPANY with significant advantages
       in reduced operational overheads when handling cross-domain
       faults.  Having a uniform VCCV feature implementation in COMPANY
       multi-vendor network leads to:

       o  Reduced operational cost and complexity

       o  Reduced OSS development to coordinate incompatible VCCV
          implementations.

       o  Increased end-end service availability when handing faults.

       In addition, currently some of COMPANY deployed VCCV traffic
       flows (on some vendor platforms) are not guaranteed to follow
       those of the customer's application traffic (a key operational
       requirement).  As a result, the response from the circuit ping
       cannot faithfully reflect the status of the circuit.  This leads
       to ambiguity regarding the operational status of our networks.
       An in-band method is highly preferred, with COMPANY having a
       clear preference for VCCV Circuit Ping using PWE Control Word.
       This preference is being pursued with each of COMPANY vendors.

   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.  Interoperability
       challenges are with Ethernet OAM mechanism.

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   5.  We are using L2PVPN AToM like-to-like models - ATMoMPLS - EoMPLS
       ATMoMPLS : This service offered for transporting ATM cells over
       IP/MPLS core with Edge ATM CE devices including BPX, Ericsson
       Media Gateway etc.  This is purely a Port mode with cell-packing
       configuration on it to have best performance.  QoS marking is
       done for getting LLQ treatment in the core for these MPLS
       encapsulated ATM packets.  EoMPLS: This service offered for
       transporting 2G/3G traffic from network such as Node-B to RNC's
       over IP/MPLS backbone core network.  QoS marking is done for
       getting guaranteed bandwidth treatment in the core for these MPLS
       encapsulated ATM packets.  In addition to basic L2VPN service
       configuration, these traffic are routed via MPLS TE tunnels with
       dedicated path and bandwidth defined to avoid bandwidth related
       congestion.

   6.  EQUIPMENT MANUFACTURER does not provide options to configure VCCV
       control-channel and its sub options for LDP based L2Circuits.
       How can we achieve end-to-end management and fault detection of
       PW without VCCV in such cases?

   7.  I'm very interested in this work as we continue to experience
       interop challenges particularly with newer vendors to the space
       who are only implementing VCCV via control word.  Vendors who
       have tailed their MPLS OAM set specifically to the cell backhaul
       space and mandatory CW have been known to fall into this space.
       That's all I've got.

3.  Security Considerations

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

4.  Acknowledgements

   We would like to thank the chairs of the PWE3 working group for their
   guidance and review of the survey questions.  We would also like to
   sincerely thank those listed in Section 2.2. who took the time and
   effort to participate.

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5.  Informative References

   [RFC4448]  Martini, L., Rosen, E., El-Aawar, N., and G. Heron,
              "Encapsulation Methods for Transport of Ethernet over MPLS
              Networks", RFC 4448, April 2006.

   [RFC4618]  Martini, L., Rosen, E., Heron, G., and A. Malis,
              "Encapsulation Methods for Transport of PPP/High-Level
              Data Link Control (HDLC) over MPLS Networks", RFC 4618,
              September 2006.

   [RFC4717]  Martini, L., Jayakumar, J., Bocci, M., El-Aawar, N.,
              Brayley, J., and G. Koleyni, "Encapsulation Methods for
              Transport of Asynchronous Transfer Mode (ATM) over MPLS
              Networks", RFC 4717, December 2006.

   [RFC5085]  Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual
              Circuit Connectivity Verification (VCCV): A Control
              Channel for Pseudowires", December 2007.

   [RFC6307]  Black, D., Dunbar, L., Roth, M., and R. Solomon,
              "Encapsulation Methods for Transport of Fibre Channel
              Traffic over MPLS Networks", RFC 6307, April 2012.

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

Appendix A.  Survey Responses

   The detailed responses are included in this appendix.  The respondent
   contact info has been removed.

A.1.  Respondent 1

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 423

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

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A.2.  Respondent 2

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       SAToP - RFC 4553

       CESoPSN - RFC 5086

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 5000

       Ethernet Raw Mode - RFC 4448 - 1000

       SAToP - RFC 4553 - 50

       CESoPSN - RFC 5086 - 1600

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1), Router
       Alert Label (Type 2), TTL Expiry (Type 3)

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1), Router Alert
       Label (Type 2), TTL Expiry (Type 3)

       CESoPSN - RFC 5086: TTL Expiry (Type 3)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: ICMP Ping, LSP Ping

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

       SAToP - RFC 4553: LSP Ping

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

       CESoPSN - RFC 5086: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       I'm very interested in this work as we continue to experience
       interop challenges particularly with newer vendors to the space
       who are only implementing VCCV via control word.  Vendors who
       have tailed their MPLS OAM set specifically to the cell backhaul
       space and mandatory CW have been known to fall into this space.
       That's all I've got.

A.3.  Respondent 3

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       Frame Relay (Port Mode) - RFC 4619

       Frame Relay (1:1 Mode) - RFC 4619

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 800

       Ethernet Raw Mode - RFC 4448 - 50

       Frame Relay (Port Mode) - RFC 4619 - 2

       Frame Relay (1:1 Mode) - RFC 4619 - 2

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   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       No Response

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       No Response

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.4.  Respondent 4

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 1000

       Ethernet Raw Mode - RFC 4448 - 200

Del Regno & Malis             Informational                    [Page 23]
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   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       No Response

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

       Ethernet Raw Mode - RFC 4448: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       EQUIPMENT MANUFACTURER does not provide options to configure VCCV
       control-channel and its sub options for LDP based L2Circuits.
       How can we achieve end-to-end management and fault detection of
       PW without VCCV in such cases?

A.5.  Respondent 5

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       PPP - RFC 4618

       Frame Relay (Port Mode) - RFC 4619

       Frame Relay (1:1 Mode) - RFC 4619

       Fiber Channel (Port Mode) - "Encapsulation Methods for Transport
       of Fibre Channel" (now RFC 6307)

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   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 4000

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1), Router
       Alert Label (Type 2)

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1), Router Alert
       Label (Type 2)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.6.  Respondent 6

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

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   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 1000+

       Ethernet Raw Mode - RFC 4448 - 500

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1)

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: ICMP Ping, LSP Ping

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

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A.7.  Respondent 7

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Raw Mode - RFC 4448

       ATM (1:1 Mode) - RFC 4717

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Raw Mode - RFC 4448 - 20

       ATM (1:1 Mode) - RFC 4717 - 100

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       No Response

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Raw Mode - RFC 4448: LSP Ping

       ATM (1:1 Mode) - RFC 4717: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode), PPP, HDLC, Frame Relay (Port Mode), ATM (N:1 Cell
       Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

       We are using L2PVPN AToM like-to-like models - ATMoMPLS - EoMPLS
       ATMoMPLS : This service offered for transporting ATM cells over
       IP/MPLS core with Edge ATM CE devices including BPX, Ericsson
       Media Gateway etc.  This is purely a Port mode with cell-packing
       configuration on it to have best performance.  QoS marking is
       done for getting LLQ treatment in the core for these MPLS
       encapsulated ATM packets.  EoMPLS: This service offered for
       transporting 2G/3G traffic from network such as Node-B to RNC's
       over IP/MPLS backbone core network.  QoS marking is done for
       getting guaranteed bandwidth treatment in the core for these MPLS
       encapsulated ATM packets.  In addition to basic L2VPN service
       configuration, these traffic are routed via MPLS TE tunnels with
       dedicated path and bandwidth defined to avoid bandwidth related
       congestion.

A.8.  Respondent 8

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Raw Mode - RFC 4448

       ATM (AAL5 SDU Mode) - RFC 4717

       TDMoIP - RFC 5087

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Raw Mode - RFC 4448 - In-Use

       ATM (AAL5 SDU Mode) - RFC 4717 - In-Use

       TDMoIP - RFC 5087 - In-Use

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1)

       ATM (AAL5 SDU Mode) - RFC 4717: Router Alert Label (Type 2)

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   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Raw Mode - RFC 4448: LSP Ping

       ATM (AAL5 SDU Mode) - RFC 4717: LSP Ping

       TDMoIP - RFC 5087: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Raw Mode), ATM (N:1
       Cell Mode)

       Used in Network: Ethernet (Raw Mode), ATM (N:1 Cell Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       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.  Interoperability
       challenges are with Ethernet OAM mechanism.

A.9.  Respondent 9

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Frame Relay (1:1 Mode) - RFC 4619

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 19385

       Frame Relay (1:1 Mode) - RFC 4619 - 15757

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   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Frame Relay (1:1 Mode) - RFC 4619: Control Word (Type 1)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Frame Relay (1:1 Mode) - RFC 4619: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode), PPP, HDLC, Frame Relay (Port Mode), ATM (N:1 Cell
       Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.10.  Respondent 10

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Raw Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Raw Mode - RFC 4448 - 325

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1)

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   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: No Response

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.11.  Respondent 11

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       PPP - RFC 4618 HDLC - RFC 4618

       Frame Relay (1:1 Mode) - RFC 4619

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 2000

       Ethernet Raw Mode - RFC 4448 - 100

       PPP - RFC 4618 - 500

       Frame Relay (1:1 Mode) - RFC 4619 - 200

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   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       No Response

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: ICMP Ping, LSP Ping

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

       Frame Relay (1:1 Mode) - RFC 4619: ICMP Ping, LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode), PPP, HDLC

       Used in Network: Ethernet (Tagged Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.12.  Respondent 12

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Raw Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Raw Mode - RFC 4448 - 50000

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   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1), Router Alert
       Label (Type 2), TTL Expiry (Type 3)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       No Response

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.13.  Respondent 13

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       Frame Relay (1:1 Mode) - RFC 4619

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 3

       Ethernet Raw Mode - RFC 4448 - 10-20

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       ATM (1:1 Mode) - RFC 4717 - 3

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1), TTL
       Expiry (Type 3)

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1), TTL Expiry
       (Type 3)

       Frame Relay (1:1 Mode) - RFC 4619: Control Word (Type 1), TTL
       Expiry (Type 3)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: ICMP Ping, LSP Ping

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

       Frame Relay (1:1 Mode) - RFC 4619: ICMP Ping, LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode), PPP, HDLC, Frame Relay (Port Mode), ATM (N:1 Cell
       Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode),
       Frame Relay (Port Mode)

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

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A.14.  Respondent 14

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 150

       Ethernet Raw Mode - RFC 4448 - 100

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1), Router
       Alert Label (Type 2)

       Ethernet Raw Mode - RFC 4448: Control Word (Type 1), Router Alert
       Label (Type 2)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

       Ethernet Raw Mode - RFC 4448: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode), PPP, HDLC, Frame Relay (Port Mode)

       Used in Network: Ethernet (Tagged Mode), Ethernet (Raw Mode)

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   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       No Response

A.15.  Respondent 15

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

       Frame Relay (1:1 Mode) - RFC 4619

       ATM (1:1 Mode) - RFC 4717

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 20,000

       Ethernet Raw Mode - RFC 4448 - 1000

       Frame Relay (1:1 Mode) - RFC 4619 - 30,000

       ATM (1:1 Mode) - RFC 4717 - 20,000

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: TTL Expiry (Type 3)

       Ethernet Raw Mode - RFC 4448: TTL Expiry (Type 3)

       Frame Relay (1:1 Mode) - RFC 4619: TTL Expiry (Type 3)

       ATM (1:1 Mode) - RFC 4717: TTL Expiry (Type 3)

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   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

       Ethernet Raw Mode - RFC 4448: LSP Ping

       Frame Relay (1:1 Mode) - RFC 4619: LSP Ping

       ATM (1:1 Mode) - RFC 4717: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: No Response

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       COMPANY has deployed several MPLS network elements, from multiple
       vendors.  COMPANY is seeking a uniform implementation of VCCV
       Control Channel (CC) capabilities across its various vendor
       platforms.  This will provide COMPANY with significant advantages
       in reduced operational overheads when handling cross-domain
       faults.  Having a uniform VCCV feature implementation in COMPANY
       multi-vendor network leads to:

       o   Reduced operational cost and complexity

       o   Reduced OSS development to coordinate incompatible VCCV
           implementations.

       o   Increased end-end service availability when handing faults.

       In addition, currently some of COMPANY deployed VCCV traffic
       flows (on some vendor platforms) are not guaranteed to follow
       those of the customer's application traffic (a key operational
       requirement).  As a result, the response from the circuit ping
       cannot faithfully reflect the status of the circuit.  This leads
       to ambiguity regarding the operational status of our networks.
       An in-band method is highly preferred, with COMPANY having a
       clear preference for VCCV Circuit Ping using PWE Control Word.
       This preference is being pursued with each of COMPANY vendors.

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A.16.  Respondent 16

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       Ethernet Raw Mode - RFC 4448

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - 100

       Ethernet Raw Mode - RFC 4448 - 100

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       No Response

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: ICMP Ping, LSP Ping

       Ethernet Raw Mode - RFC 4448: ICMP Ping, LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: Ethernet (Tagged Mode), Ethernet
       (Raw Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

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       Using CV is not required at the moment

A.17.  Respondent 17

   2.  In your network in general, across all products, please indicate
       which pseudowire encapsulations your company has implemented.

       Ethernet Tagged Mode - RFC 4448

       SAToP - RFC 4553

       Frame Relay (Port Mode) - RFC 4619

       Frame Relay (1:1 Mode) - RFC 4619

       ATM (N:1 Mode) - RFC 4717

       ATM (1:1 Mode) - RFC 4717

       CESoPSN - RFC 5086

       TDMoIP - RFC 5087

   3.  Approximately how many pseudowires are deployed of each
       encapsulation type.  Note, this should be the number of
       pseudowires in service, carrying traffic, or pre-positioned to do
       so. ***Note, please indicate "In-Use" for any PW Encap Types
       which you are using but cannot provide a number.

       Ethernet Tagged Mode - RFC 4448 - >40k

       Ethernet Raw Mode - RFC 4448 - In-Use

       SAToP - RFC 4553 - >20k

       Frame Relay (Port Mode) - RFC 4619 - >5k

       Frame Relay (1:1 Mode) - RFC 4619 - >5k

       ATM (N:1 Mode) - RFC 4717 - >50k

       ATM (1:1 Mode) - RFC 4717 - >50k

       CESoPSN - RFC 5086 - >20k

       TDMoIP - RFC 5087 - >20k

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RFC 7079          PW/VCCV Implementation Survey Results    November 2013

   4.  Please indicate which VCCV Control Channel is used for each
       encapsulation type.  Understanding that users may have different
       networks with varying implementations, for your network in
       general, please select all which apply.

       Ethernet Tagged Mode - RFC 4448: Control Word (Type 1)

       SAToP - RFC 4553: Control Word (Type 1)

       Frame Relay (Port Mode) - RFC 4619: Control Word (Type 1)

       Frame Relay (1:1 Mode) - RFC 4619: Control Word (Type 1)

       ATM (N:1 Mode) - RFC 4717: Control Word (Type 1)

       ATM (1:1 Mode) - RFC 4717: Control Word (Type 1)

   5.  Please indicate which VCCV Connectivity Verification types are
       used in your networks for each encapsulation type.

       Ethernet Tagged Mode - RFC 4448: LSP Ping

       SAToP - RFC 4553: LSP Ping

       Frame Relay (Port Mode) - RFC 4619: LSP Ping

       Frame Relay (1:1 Mode) - RFC 4619: LSP Ping

       ATM (N:1 Mode) - RFC 4717: LSP Ping

       ATM (1:1 Mode) - RFC 4717: LSP Ping

   6.  Please indicate your network's support of and use of the Control
       Word for encapsulations for which the Control Word is optional.

       Supported by Network/Equipment: ATM (N:1 Cell Mode)

       Used in Network: No Response

   7.  Please use this space to provide any feedback regarding PW and
       VCCV deployments, VCCV interoperability challenges, this survey
       or any network/vendor details you wish to share.

       BFD VCCV Control Channel is not indicated in the survey (may be
       required for PW redundancy purpose)

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Authors' Addresses

   Christopher N. "Nick" Del Regno (editor)
   Verizon Communications, Inc.
   400 International Pkwy
   Richardson, TX  75081
   US

   EMail: nick.delregno@verizon.com

   Andrew G. Malis (editor)
   Consultant

   EMail: agmalis@gmail.com

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