[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 RFC 7152

Network Working Group                       Raymond Key (editor), Huawei
Internet Draft                                     Simon Delord, Telstra
Category: Informational                       Frederic Jounay, Orange CH
Expires: October 2013                             Lu Huang, China Mobile
                                               Zhihua Liu, China Telecom
                                           Manuel Paul, Deutsche Telekom
                                        Ruediger Kunze, Deutsche Telekom
                                                 Nick Del Regno, Verizon
                                          Josh Rogers, Time Warner Cable


                                                           April 4, 2013


              Requirements for MEF E-Tree Support in L2VPN
                    draft-ietf-l2vpn-etree-reqt-04


Abstract

   This document provides functional requirements for Metro Ethernet
   Forum (MEF) Ethernet Tree (E-Tree) support in multipoint L2VPN
   solutions (referred to as simply L2VPN). It is intended that
   potential solutions will use these requirements as guidelines.


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on October 4, 2013.





Key, et al.               Expires October 2013                 [Page 1]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


Table of Contents

   1. Introduction....................................................3
   2. IETF Multipoint Ethernet L2VPN Services.........................3
   2.1. VPLS..........................................................3
   2.2. E-VPN.........................................................3
   3. MEF Multipoint Ethernet Services................................3
   3.1. Similarity between E-LAN and E-Tree...........................3
   3.2. Difference between E-LAN and E-Tree...........................4
   3.3. E-Tree Use Cases..............................................4
   3.4. Generic E-Tree Service........................................5
   4. Problem Statement...............................................5
   4.1. Motivation....................................................5
   4.2. Leaf-to-Leaf Communication Restriction........................5
   5. Requirements....................................................6
   5.1. Functional Requirements.......................................6
   5.2. Applicability.................................................6
   5.3. Backward Compatibility........................................7
   5.4. External Network Network Interface............................7
   6. Security Consideration..........................................7
   7. IANA Considerations.............................................7
   8. Acknowledgements................................................7
   9. References......................................................7
   9.1. Normative References..........................................7
   9.2. Informative References........................................8
   Appendix
   A. Frequently Asked Questions......................................9
   A.1. Are E-Tree requirements addressed in the Virtual
        Private Multicast Service (VPMS) requirements?................9
   A.2. Are there any potential deployment scenarios for
        a "VPLS Only" solution?......................................10
   Authors' Addresses................................................13
   Intellectual Property and Copyright Statements....................14


Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].













Key, et al.               Expires October 2013                 [Page 2]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


1. Introduction

   This document provides functional requirements for Metro Ethernet
   Forum (MEF) Ethernet Tree (E-Tree) support in multipoint L2VPN
   solutions (referred to as simply L2VPN). It is intended that
   potential solutions will use these requirements as guidelines.

   Considerable number of service providers have adopted VPLS to provide
   MEF Ethernet LAN (E-LAN) services to customers. Service Providers
   currently need a simple and effective solution to emulate E-Tree
   services in addition to E-LAN services on their MPLS networks.

   Service providers also expect E-Tree support in any newly developed
   L2VPN technologies.

2. IETF Multipoint Ethernet L2VPN Services

2.1. VPLS

   VPLS [RFC4761] [RFC4762] is a L2VPN service that provides multipoint-
   to-multipoint connectivity for Ethernet across an IP or MPLS-enabled
   IP Packet Switched Network (PSN). VPLS emulates the Ethernet Virtual
   Local Area Network (VLAN) functionality of traditional Ethernet
   networks. Thus, in VPLS, the customer Ethernet frame is transported
   over the IP/MPLS PSN from the ingress Provider Edge (PE) to the
   egress PE where the destination is connected based on the Ethernet
   frame destination MAC address.

2.2. E-VPN

   E-VPN is an enhanced Layer-2 service that emulates an Ethernet VLAN
   across a PSN, primarily targeted to support large scale L2VPNs with
   resiliency requirements not satisfied by other L2VPN solutions.

   E-VPN is currently under development. Please refer to [Draft EVPN
   Req].

3. MEF Multipoint Ethernet Services

   MEF has defined two multipoint Ethernet Service types:
     - E-LAN (Ethernet LAN), multipoint-to-multipoint service
     - E-Tree (Ethernet Tree), rooted-multipoint service

   For full specification, please refer to [MEF6.1] [MEF10.2].

3.1. Similarity between E-LAN and E-Tree

   Following are the similarities between E-LAN and E-Tree services.
     - Data frame is Ethernet frame.
     - Data forwarding can be MAC-based forwarding, to be specified by
       service provider as service frame delivery attributes in the
       particular service definition.

Key, et al.               Expires October 2013                 [Page 3]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


     - A generic E-LAN/E-Tree service is always bidirectional in the
       sense that ingress frames can originate at any endpoint in the
       service.

3.2. Difference between E-LAN and E-Tree

   Within the context of a multipoint Ethernet service, each endpoint is
   designated as either a Root or a Leaf. A Root can communicate with
   all other endpoints in the same multipoint Ethernet service, however
   a Leaf can only communicate with Roots but not Leafs.

   The only difference between E-LAN and E-Tree is:
     - E-LAN has Root endpoints only, which implies there is no
       communication restriction between endpoints.
     - E-Tree has both Root and Leaf endpoints, which implies there is a
       need to enforce communication restriction between Leaf endpoints.

3.3. E-Tree Use Cases

   Table 1 below presents some major E-Tree use cases.

       +---------------------------+--------------+------------+
       | Use Case                  | Root         | Leaf       |
   +---+---------------------------+--------------+------------+
   | 1 | Hub & Spoke VPN           | Hub Site     | Spoke Site |
   +---+---------------------------+--------------+------------+
   | 2 | Wholesale Access          | Customer's   | Customer's |
   |   |                           | Interconnect | Subscriber |
   +---+---------------------------+--------------+------------+
   | 3 | Mobile Backhaul           | RAN Network  | RAN Base   |
   |   |                           | Controller   | Station    |
   +---+---------------------------+--------------+------------+
   | 4 | IEEE 1588 PTPv2           | PTP Server   | PTP Client |
   |   | Clock Synchronisation     |              |            |
   +---+---------------------------+--------------+------------+
   | 5 | Internet Access           | Broadband    | Subscriber |
   |   | [TR-101]                  | Network      |            |
   |   |                           | Gateway      |            |
   +---+---------------------------+--------------+------------+
   | 6 | Broadcast Video           | Video Source | Subscriber |
   |   | (unidirectional only)     |              |            |
   +---+---------------------------+--------------+------------+
   | 7 | Broadcast/Multicast Video | Video Source | Subscriber |
   |   | plus Control Channel      |              |            |
   +---+---------------------------+--------------+------------+
   | 8 | Device Management         | Management   | Managed    |
   |   |                           | System       | Device     |
   +---+---------------------------+--------------+------------+

                     Table 1: E-Tree Use Cases



Key, et al.               Expires October 2013                 [Page 4]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


   Common to all use cases, direct layer 2 Leaf-to-Leaf communication is
   not required. For Mobile backhaul, this may not be valid for LTE X2
   interfaces [MEF22.1].

   If direct layer 2 Leaf-to-Leaf communication is not allowed due to
   security concern, then E-Tree should be used to prohibit
   communication between Leaf endpoints, otherwise E-LAN is also a
   feasible option.

3.4. Generic E-Tree Service

   A generic E-Tree service supports multiple Root endpoints. The need
   for multiple Root endpoints is usually driven by redundancy
   requirement. Whether a particular E-Tree service needs to support
   single or multiple Roots depends on the target application.

   A generic E-Tree service supports all the following traffic flows:
     - Ethernet Unicast from Root to Leaf
     - Ethernet Unicast from Leaf to Root
     - Ethernet Unicast from Root to Root
     - Ethernet Broadcast/Multicast from Root to Roots & Leafs
     - Ethernet Broadcast/Multicast from Leaf to Roots
   A particular E-Tree service may need to support all the above or only
   a subset depending on the target application.

4. Problem Statement

4.1. Motivation

   L2VPN can be used to emulate MEF E-LAN service over an MPLS network
   provided that the E-LAN service uses MAC-based forwarding as a
   service frame delivery attributes.

   Service providers also require E-Tree support in L2VPN.

4.2. Leaf-to-Leaf Communication Restriction

   In this section, VPLS is used to illustrate the problem, but the same
   principle applies to other L2VPN technologies.

   VPLS treats all attachment circuits (ACs) equal (i.e. not classified
   into Root or Leaf) and provides any-to-any connectivity among all
   ACs. VPLS does not include any mechanism of communication restriction
   between specific ACs, therefore it is insufficient for emulating
   generic E-Tree service over IP/MPLS PSN.

   As an example of the problems not addressed in VPLS solutions,
   consider the scenario in Figure 1 where there are two PEs, each with
   a Root AC and a Leaf AC and where VPLS is used to emulate an E-Tree
   service over an MPLS network.



Key, et al.               Expires October 2013                 [Page 5]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


                     <------------E-Tree------------>
                    +---------+            +---------+
                    |   PE1   |            |   PE2   |
   +---+            |  +---+  |            |  +---+  |            +---+
   |CE1+-----AC1----+--+   |  |            |  |   +--+----AC3-----+CE3|
   +---+  (Root AC) |  | V |  |  Ethernet  |  | V |  | (Root AC)  +---+
                    |  | S +--+-----PW-----+--+ S |  |
   +---+            |  | I |  |            |  | I |  |            +---+
   |CE2+-----AC2----+--+   |  |            |  |   +--+----AC4-----+CE4|
   +---+  (Leaf AC) |  +---+  |            |  +---+  | (Leaf AC)  +---+
                    +---------+            +---------+

   Figure 1: Problem Scenario for Leaf-to-Leaf Communication Restriction

   When PE2 receives a frame from PE1 via the Ethernet PW,
     - PE2 does not know which AC on PE1 is the ingress AC
     - PE2 does not know whether the ingress AC is a Leaf AC or not
     - PE2 does not have sufficient information to enforce the
       Leaf-to-Leaf communication restriction

   Examples where the problems arise:
     - CE2 sends a Broadcast/Multicast frame to PE1 via AC2
     - CE2 sends a Unicast frame to PE1 via AC2 with destination MAC
       address corresponding to CE4's MAC address

   Note: Figure 1 is a hypothetical case solely used for explaining the
   problem, and not meant to represent a typical E-Tree service.

   There are some possible ways to get around this problem that do not
   require extension to existing VPLS solutions but they all come with
   significant design complexity or deployment constraints, please refer
   to [Draft ETree Frwk] Appendix A.

5. Requirements

5.1. Functional Requirements

   A solution MUST prohibit communication between any two Leaf ACs in a
   L2VPN instance.

   A solution MUST allow multiple Root ACs in a L2VPN instance.

   A solution MUST allow Root AC and Leaf AC of a L2VPN instance to
   co-exist on any PE.

5.2. Applicability

   A solution MUST identify the L2VPN technology ([RFC4761], [RFC4762],
   E-VPN) the solution is applicable to.




Key, et al.               Expires October 2013                 [Page 6]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


5.3. Backward Compatibility

   A solution SHOULD minimise the impact on VPLS and E-VPN L2VPN
   solutions, especially for the MEF E-LAN services already in
   operation.

   A solution SHOULD be backward compatible with the VPLS and E-VPN
   L2VPN solutions. It SHOULD allow a case where a common L2VPN instance
   is composed of both PEs supporting the solution and PEs not
   supporting it, and the Leaf-to-Leaf communication restriction is
   enforced within the scope of the compliant PEs.

5.4. External Network Network Interface

   A solution SHOULD support Root Operator Virtual Connection (OVC) End
   Point, Leaf OVC End Point and Trunk OVC End Point specified in
   [MEF26.1].

6. Security Considerations

   This document introduces a requirement of prohibiting communication
   between any two Leaf ACs in a L2VPN instance. In some use cases, such
   requirement is imposed because of security reasons. Other than that,
   there are no additional security considerations beyond those already
   described in [RFC4761] [RFC4762].

7. IANA Considerations

   This document has no actions for IANA.

8. Acknowledgements

   The authors would like to thank Lizhong Jin, Lucy Yong, Yuji Kamite
   and Wim Henderickx for their valuable input and support.

9. References

9.1. Normative References

   [MEF6.1]     Metro Ethernet Forum, Ethernet Services Definitions -
                Phase 2, April 2008

   [MEF10.2]    Metro Ethernet Forum, Ethernet Services Attributes -
                Phase 2, October 2009

   [MEF22.1]    Metro Ethernet Forum, Mobile Backhaul Implementation
                Agreement - Phase 2, January 2012

   [MEF26.1]    Metro Ethernet Forum, External Network Network Interface
                (ENNI) - Phase 2, January 2012



Key, et al.               Expires October 2013                 [Page 7]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


   [RFC2119]    Bradner, S., Key words for use in RFCs to Indicate
                Requirement Levels, BCP 14, RFC 2119, March 1997

   [RFC4761]    Kompella & Rekhter, Virtual Private LAN Service (VPLS)
                Using BGP for Auto-Discovery and Signaling, January 2007

   [RFC4762]    Lasserre & Kompella, Virtual Private LAN Service (VPLS)
                Using Label Distribution Protocol (LDP) Signaling,
                January 2007

9.2. Informative References

   [Draft EVPN Req]
                Sajassi, Aggarwal, et al., Requirements for Ethernet VPN
                (E-VPN), draft-ietf-l2vpn-evpn-req-02 (work in
                progress), February 2013

   [TR-101]     Broadband Forum, Migration to Ethernet-Based Broadband
                Aggregation Issue 2, July 2011

   [Draft ETree Frwk]
                Key, et al., A Framework for E-Tree Service over MPLS
                Network, draft-ietf-l2vpn-etree-frwk-02 (work in
                progress), February 2013

   [Draft VPMS Frmwk]
                Kamite, et al., Framework and Requirements for Virtual
                Private Multicast Service (VPMS),
                draft-ietf-l2vpn-vpms-frmwk-requirements-05 (work in
                progress), October 2012























Key, et al.               Expires October 2013                 [Page 8]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


Appendix A. Frequently Asked Questions

A.1. Are E-Tree requirements addressed in the Virtual Private Multicast
     Service (VPMS) requirements?

   VPMS requirements are defined in [Draft VPMS Frmwk].

   The focus of VPMS is to provide point-to-multipoint connectivity.

   VPMS provides single coverage of receiver membership (i.e. there is
   no distinct differentiation for multiple multicast groups). A VPMS
   service supports single or multiple Root ACs. All traffic from a Root
   AC will be forwarded to all Leaf ACs (i.e. P2MP, from Root to all
   Leafs). Destination address in Ethernet frame is not used in data
   forwarding. As an optional capability, a VPMS service may support
   reverse traffic from a Leaf AC to a Root AC (i.e. P2P, from Leaf to
   Root).

   In contrast, the focus of MEF E-Tree is that a Leaf can only
   communicate with Roots but not Leafs.

   A generic MEF E-Tree service supports multiple Root endpoints.
   Whether a particular E-Tree service needs to support single or
   multiple Root endpoints depends on the target application.

   A generic MEF E-Tree service supports all the following traffic
   flows:
     - Ethernet Unicast bidirectional Root to/from Root
     - Ethernet Unicast bidirectional Root to/from Leaf
     - Ethernet Broadcast/Multicast unidirectional Root to all Roots &
       Leafs
     - Ethernet Broadcast/Multicast unidirectional Leaf to all Roots.
   A particular E-Tree service may need to support all the above or only
   a subset depending on the target application.

   IETF's VPMS definition and MEF's E-Tree definition are significantly
   different.

   Only for special case E-Tree service where
     - No Unicast traffic from Root destined for a specific Leaf (or
       there is no concern if such Unicast traffic is forwarded to all
       Leafs)
     - No traffic between Roots
   VPMS will be able to meet the requirement. An example is E-Tree
   service for content delivery application.

   For generic E-Tree service, VPMS will not be able to meet the
   requirements.





Key, et al.               Expires October 2013                 [Page 9]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


A.2. Are there any potential deployment scenarios for a "VPLS Only"
     solution?

   Yes, there are potential deployment scenarios for a "VPLS Only"
   solution with enhancements to support E-Tree services, some examples
   below.

   Example 1 -

                                                   Enhanced VPLS with
              <-----Physical P2P Service------><-----E-Tree Support-----
                                               +---------+
              +---+                            |   PE1   |
   +---+      |NTU|                            |  +---+  |
   |CE1+------+---+--V1-----------------AC1----+--+   |  |
   +---+ Root +---+                  (Root AC) |  | V |  |
                                               |  |   |  | Ethernet
              +---+                            |  | S +--+----PW--->PE2
   +---+      |NTU|                            |  |   |  |
   |CE2+------+---+--V2-----------------AC2----+--+ I |  |
   +---+ Root +---+                  (Root AC) |  |   |  |
                                               |  |   |  |
              +---+                            |  |   |  |
   +---+      |NTU|                            |  |   |  |
   |CE3+------+---+--V3-----------------AC3----+--+   |  |
   +---+ Root +---+                  (Root AC) |  |   |  |
                                               |  |   |  |
              +---+                            |  |   |  |
   +---+      |NTU|                            |  |   |  |
   |CE4+------+---+--V4-----------------AC4----+--+   |  |
   +---+ Leaf +---+                  (Leaf AC) |  |   |  |
                                               |  |   |  |
              +---+                            |  |   |  |
   +---+      |NTU|                            |  |   |  |
   |CE5+------+---+--V5-----------------AC5----+--+   |  |
   +---+ Leaf +---+                  (Leaf AC) |  +---+  |
                                               +---------+
















Key, et al.               Expires October 2013                 [Page 10]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


   Example 2 -

                     Logical P2P Service           Enhanced VPLS with
              <-------via Access Switch-------><-----E-Tree Support-----
                         +---------+           +---------+
                         | Access  |           |   PE1   |
              +---+      | Switch  |           |         |
   +---+      |NTU|      |         |           |  +---+  |
   |CE1+------+---+--V1--+--VLAN1--+--V1--AC1--+--+   |  |
   +---+ Root +---+      |         | (Root AC) |  | V |  |
                         +---------+           |  |   |  | Ethernet
                                               |  | S +--+----PW--->PE2
                         +---------+           |  |   |  |
                         | Access  |           |  | I |  |
              +---+      | Switch  |           |  |   |  |
   +---+      |NTU|      |         |           |  |   |  |
   |CE2+------+---+--V2--+--VLAN2--+--V2--AC2--+--+   |  |
   +---+ Root +---+      |         | (Root AC) |  |   |  |
                         |         |           |  |   |  |
              +---+      |         |           |  |   |  |
   +---+      |NTU|      |         |           |  |   |  |
   |CE3+------+---+--V3--+--VLAN3--+--V3--AC3--+--+   |  |
   +---+ Root +---+      |         | (Root AC) |  |   |  |
                         |         |           |  |   |  |
              +---+      |         |           |  |   |  |
   +---+      |NTU|      |         |           |  |   |  |
   |CE4+------+---+--V4--+--VLAN4--+--V4--AC4--+--+   |  |
   +---+ Leaf +---+      |         | (Leaf AC) |  |   |  |
                         |         |           |  |   |  |
              +---+      |         |           |  |   |  |
   +---+      |NTU|      |         |           |  |   |  |
   |CE5+------+---+--V5--+--VLAN5--+--V5--AC5--+--+   |  |
   +---+ Leaf +---+      |         | (Leaf AC) |  +---+  |
                         +---------+           +---------+



















Key, et al.               Expires October 2013                 [Page 11]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


   Example 3 -

                     Ethernet Switching            Enhanced VPLS with
              <------with Split Horizon-------><-----E-Tree Support-----
                         +---------+           +---------+
                         | Access  |           |   PE1   |
                         | Switch  |           |         |
                         |         |           |         |
                         |  +---+  |           |  +---+  |
              +---+      |  | V |  |           |  |   |  |
   +---+      |NTU|      |  | L |  |           |  | V |  |
   |CE1+------+---+--V1--+--+ A +--+--V1--AC1--+--+   |  |
   +---+ Root +---+      |  | N |  | (Root AC) |  | S |  |
                         |  | 1 |  |           |  |   |  | Ethernet
                         |  +---+  |           |  | I +--+----PW--->PE2
                         +---------+           |  |   |  |
                                               |  |   |  |
                         +---------+           |  |   |  |
                         | Access  |           |  |   |  |
                         | Switch  |           |  |   |  |
              +---+      |         |           |  |   |  |
   +---+      |NTU|      |  +---+  |           |  |   |  |
   |CE2+------+---+--V2--+--+ V |  |           |  |   |  |
   +---+ Root +---+      |  | L |  |           |  |   |  |
                         |  | A +--+--V2--AC2--+--+   |  |
              +---+      |  | N |  | (Root AC) |  |   |  |
   +---+      |NTU|      |  | 2 |  |           |  |   |  |
   |CE3+------+---+--V2--+--+   |  |           |  |   |  |
   +---+ Root +---+      |  +---+  |           |  |   |  |
                         |         |           |  |   |  |
              +---+      |         |           |  |   |  |
   +---+      |NTU|      |  +---+  |           |  |   |  |
   |CE4+------+---+--V4--+SH+ V |  |           |  |   |  |
   +---+ Leaf +---+      |  | L |  |           |  |   |  |
                         |  | A +--+--V4--AC4--+--+   |  |
              +---+      |  | N |  | (Leaf AC) |  |   |  |
   +---+      |NTU|      |  | 4 |  |           |  |   |  |
   |CE5+------+---+--V4--+SH+   |  |           |  |   |  |
   +---+ Leaf +---+      |  +---+  |           |  +---+  |
                         +---------+           +---------+

   Note:
     - Group Roots and Leafs into two separate VLANs on Access Switch
     - SH means member of split horizon group on Access Switch









Key, et al.               Expires October 2013                 [Page 12]

Internet Draft         Requirement E-Tree in L2VPN            April 2013


Authors' Addresses

   Raymond Key (editor)
   Huawei
   Email: raymond.key@ieee.org

   Simon Delord
   Telstra
   Email: simon.delord@gmail.com

   Frederic Jounay
   Orange CH
   4 rue caudray 1020 Renens
   Switzerland
   Email: frederic.jounay@orange.ch

   Lu Huang
   China Mobile
   Unit 2, 28 Xuanwumenxi Ave, Xuanwu District
   Beijing 100053, China
   Email: huanglu@chinamobile.com

   Zhihua Liu
   China Telecom
   109 Zhongshan Ave., Guangzhou
   510630, China
   Email: zhliu@gsta.com

   Manuel Paul
   Deutsche Telekom
   Winterfeldtstr. 21-27
   10781 Berlin, Germany
   Email: manuel.paul@telekom.de

   Ruediger Kunze
   Deutsche Telekom
   Winterfeldtstr. 21-27
   10781 Berlin, Germany
   Email: ruediger.kunze@telekom.de

   Nick Del Regno
   Verizon
   400 International Pkwy
   Richardson, TX 75081, USA
   Email: nick.delregno@verizon.com

   Josh Rogers
   Time Warner Cable
   11921 N Mo Pac Expy
   Suite 210B
   Austin, TX 78759, USA
   Email: josh.rogers@twcable.com

Key, et al.               Expires October 2013                 [Page 13]

Internet Draft         Requirement E-Tree in L2VPN            April 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.







































Key, et al.               Expires October 2013                 [Page 14]


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/