Internet Engineering Task Force                             E. Gray, Ed.
Internet-Draft                                                  Ericsson
Intended status: Informational                                  N. Bitar
Expires: January 16, 2014                                        Verizon
                                                                 X. Chen
                                                     Huawei Technologies
                                                             M. Lasserre
                                                          Alcatel-Lucent
                                                                 T. Tsou
                                               Huawei Technologies (USA)
                                                           July 15, 2013


  NVO3 Gap Analysis - Requirements Versus Available Technology Choices
                    draft-gbclt-nvo3-gap-analysis-00

Abstract

   This document evaluates candidate protocols against the NVO3
   requirements.  Gaps are identified and further work recommended.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on January 16, 2014.

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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Conventions . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     2.2.  Conventions . . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Terms and Abbreviations . . . . . . . . . . . . . . . . .   3
   3.  Operational Requirements  . . . . . . . . . . . . . . . . . .   4
   4.  Management Requirements . . . . . . . . . . . . . . . . . . .   4
   5.  Control Plane Requirements  . . . . . . . . . . . . . . . . .   4
     5.1.  Overall Control-Plane Requirements  . . . . . . . . . . .   5
     5.2.  VM-to-NVE Specific Control-Plane Requirements . . . . . .   7
   6.  Data Plane Requirements . . . . . . . . . . . . . . . . . . .   9
   7.  Summary and Conclusions . . . . . . . . . . . . . . . . . . .  14
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  15
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     11.2.  Informative References . . . . . . . . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   The initial charter of the NVO3 Working Group requires it to identify
   any gaps between the requirements identified and available
   technoloogy solutions as a prerequisite to rechartering or concluding
   the Working Group (if no gaps exist).  This document is intended to
   provide the required gap analysis.

   This document provides a tabulation of candidate solutions and their
   ability to satisfy each requirement identified by the Working Group.

   Areas of work are identified where further work is required to ensure
   that the requirements are met.

   The major areas covered in this document include:

   o  Operational Requirements
      [I-D.ashwood-nvo3-operational-requirement]

   o  Management Requirements (TBD)




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   o  Control (Plane) Requirements [I-D.kreeger-nvo3-overlay-cp]

   o  Dataplane Requirements [I-D.ietf-nvo3-dataplane-requirements]

   Since the Working Group has yet to complete (and in some cases adopt)
   documents describing requirements for some of these areas, not all
   areas are complete in the present version of this document.

   The initial candidate technologies are:

   o  NVGRE [I-D.sridharan-virtualization-nvgre],

   o  VxLAN [I-D.mahalingam-dutt-dcops-vxlan],

   o  L2VPN: VPLS [RFC4761][RFC4762] and EVPN [I-D.ietf-l2vpn-evpn], and

   o  L3VPN [RFC4365].

2.  Terminology and Conventions

2.1.  Requirements Language

   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 RFC 2119 [RFC2119].

2.2.  Conventions

   In sections providing analysis of requirements defined in referenced
   documents, section numbers from each referenced document are used as
   they were listed in that document.

   In order to avoid confusing those section numbers with the section
   numbering in this document, the included numbering is parenthesized.

   L2VPN is represented (in tables and analysis, as a technology) by the
   two differing approaches: VPLS and EVPN.

2.3.  Terms and Abbreviations

   This document uses terms and acronyms defined in [RFC3168],
   [I-D.ietf-nvo3-framework], [I-D.ietf-nvo3-dataplane-requirements],
   [I-D.kreeger-nvo3-hypervisor-nve-cp] and
   [I-D.kreeger-nvo3-overlay-cp].  Acronyms are included here for
   convenience but are meant to remain aligned with definitions in the
   references included.

   ECN:  Explicit Congestion Notification [RFC3168]



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   NVA:  Network Virtualization Authority [I-D.kreeger-nvo3-overlay-cp]

   NVE:  Network Virtualization Edge [I-D.ietf-nvo3-framework]

   VAP:  Virtual Access Point [I-D.ietf-nvo3-dataplane-requirements]

   VNI:  Virtual Network Instance [I-D.ietf-nvo3-framework]

   VNIC:  Virtual Network Interface Card (NIC)
      [I-D.kreeger-nvo3-hypervisor-nve-cp]

   VNID:  Virtual Network Identifier [I-D.kreeger-nvo3-overlay-cp]

   This document uses the following additional general terms and
   abbreviations:

   DSCP:  Differentiated Services Code-Point

   ECMP:  Equal Cost Multi-Path

   L2VPN:  Layer 2 Virtual Private Network

   L3VPN:  Layer 3 Virtual Private Network

   NVO3:  Network Virtualization Overlay over L3

   VM:  Virtual Machine

   VN:  Virtual Network

3.  Operational Requirements

   TBD

4.  Management Requirements

   TBD

5.  Control Plane Requirements

   The NVO3 Problem Statement [I-D.ietf-nvo3-overlay-problem-statement],
   describes 3 categories of control functions:

   1.  Control functions associated with implementing the Network
       Virtualization Authority (e.g. - signaling and control required
       for interactions between multiple NVA devices).





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   2.  Control functions associated with interactions between an NVA and
       a Network Virtualization Edge (NVE).

   3.  Control functions associated with attaching and detaching a
       Virtual Machine (VM) from a particular Virtual Network Instance
       (VNI).

   As sometimes happens, there is not a 1:1 mapping of the work areas
   defined in [I-D.ietf-nvo3-overlay-problem-statement] and requirements
   documents intended to address the problems that have been identified
   there.

   Current control-plane requirement documents include the following:

   o  Overall control-plane requirements [I-D.kreeger-nvo3-overlay-cp]

   o  Control-plane requirements specific to VM-to-NVE interactions
      [I-D.kreeger-nvo3-hypervisor-nve-cp]

5.1.  Overall Control-Plane Requirements

   In this section, numbering of requirement headings corresponds to
   section numbering in [I-D.kreeger-nvo3-overlay-cp].

   (3.1) Inner to Outer Address Mapping

   The requirements document [I-D.kreeger-nvo3-overlay-cp] states that
   avoiding the need to "flood" traffic to support learning of mapping
   information from the data-plane is a goal of NVO3 candidate
   technological approaches.

   For each candidate technology, (how) is the mapping of header
   information present in tenant traffic mapped to corresponding header
   information to be used in overlay encapsulation (this includes
   addresses, context identification, etc.) determined?

   +----------------------+---------+---------+-------+-------+--------+
   | Supported Approach   |  NVGRE  |  VxLAN  |  VPLS |  EVPN | L3VPN  |
   +----------------------+---------+---------+-------+-------+--------+
   | Control Protocol     |         |         |       |       |        |
   | Acquisition?         |         |         |       |       |        |
   | - - -                |  - - -  |  - - -  | - - - | - - - | - - -  |
   | Data-Plane Learning? |         |         |       |       |        |
   +----------------------+---------+---------+-------+-------+--------+

                   Table 1: Inner:Outer Address Mapping

   (3.2) Underlying Network Multi-Destination Address(es)



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   The requirements document [I-D.kreeger-nvo3-overlay-cp] lists 3
   approaches that may be used to deliver traffic to multiple
   destinations in an overlay virtual network:

   1.  Use the capabilities of the underlay network.

   2.  Require a sending NVE to replicate traffic.

   3.  Use a replication service provided within the overlay network.

   For each delivery approach, it may be necessary to map specific
   multipoint (e.g. - broadcast, unknown destination or multicast)
   traffic to (for instance) addresses used to deliver this traffic via
   the underlay network.

   For each technological approach, which delivery approaches are
   supported and does the technology provide a method by which an NVE
   needing to send multi-destination traffic can determine to what
   address, or addresses to which to send this traffic?

   +---------------------+---------+---------+--------+-------+--------+
   | Supported Approach  |  NVGRE  |  VxLAN  |  VPLS  |  EVPN | L3VPN  |
   +---------------------+---------+---------+--------+-------+--------+
   | Underlay Network    |         |         |        |       |        |
   | Capability          |         |         |        |       |        |
   | - - -               |  - - -  |  - - -  | - - -  | - - - | - - -  |
   | NVE Sender          |         |         |        |       |        |
   | Replication         |         |         |        |       |        |
   | - - -               |  - - -  |  - - -  | - - -  | - - - | - - -  |
   | Replication Service |         |         |        |       |        |
   +---------------------+---------+---------+--------+-------+--------+

                    Table 2: Multi-Destination Delivery

   (3.3) VN Connect/Disconnect Notification

   The requirements document [I-D.kreeger-nvo3-overlay-cp] states as an
   assumption that a mechanism exists in the overlay technology by which
   an NVE is notified of Tenant Systems attaching and detaching from a
   specific Virtual Network (VN).

   For each candidate technology, does the technology currently support
   these functions?

    +-------------------------+-------+-------+-------+-------+-------+
    | Requirement             | NVGRE | VxLAN |  VPLS |  EVPN | L3VPN |
    +-------------------------+-------+-------+-------+-------+-------+
    | Connect Notification    |       |       |       |       |       |



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    | - - -                   | - - - | - - - | - - - | - - - | - - - |
    | Disconnect Notification |       |       |       |       |       |
    +-------------------------+-------+-------+-------+-------+-------+

                 Table 3: Connect/Disconnect Notification

   (3.4) VN Name to VNID Mapping

   The requirements document [I-D.kreeger-nvo3-overlay-cp] concludes
   that having a means to map for a "VN Name to a "VN ID" may be useful.

   For each technological approach we are considering, is this function
   currently available?

      +-----------------------+-------+-------+------+------+-------+
      | Function              | NVGRE | VxLAN | VPLS | EVPN | L3VPN |
      +-----------------------+-------+-------+------+------+-------+
      | VN-Name:VN-ID Mapping |       |       |      |      |       |
      +-----------------------+-------+-------+------+------+-------+

                     Table 4: VN Name to VN ID Mapping

5.2.  VM-to-NVE Specific Control-Plane Requirements

   In this section, numbering of requirement headings corresponds to
   section numbering in [I-D.kreeger-nvo3-hypervisor-nve-cp].

   (4.1) VN Connect/Disconnect

   The requirements document [I-D.kreeger-nvo3-hypervisor-nve-cp] states
   as a requirement that a mechanism must exist by which an NVE is
   notified when an end device requires a connection, or no longer
   requires a connection, to a specific Virtual Network (VN).

   The requirements document further states as a requirement that the
   mechanism(s) used in a candidate technological approach must provide
   a local indicator (e.g. - 802.1Q tag) that the end device will use in
   sending traffic to, or receiving traffic from, the NVE (where that
   traffic is associated with the connected VN).

   As an additional related requirement, the requirements document
   states that the NVE - once notified of a connection to a VN (by VN
   Name), needs to have a means for getting associated VN context
   information from the NVA.

   For each candidate technology, does the technology currently support
   these functions?




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   +----------------------+---------+---------+-------+-------+--------+
   | Requirement          |  NVGRE  |  VxLAN  |  VPLS |  EVPN | L3VPN  |
   +----------------------+---------+---------+-------+-------+--------+
   | Connect Notification |         |         |       |       |        |
   | - - -                |  - - -  |  - - -  | - - - | - - - | - - -  |
   | Local VN Indicator   |         |         |       |       |        |
   | - - -                |  - - -  |  - - -  | - - - | - - - | - - -  |
   | VN Name to VN        |         |         |       |       |        |
   | Context Mapping      |         |         |       |       |        |
   | - - -                |  - - -  |  - - -  | - - - | - - - | - - -  |
   | Disconnect           |         |         |       |       |        |
   | Notification         |         |         |       |       |        |
   +----------------------+---------+---------+-------+-------+--------+

                      Table 5: VN Connect/Disconnect

   (4.2) VNIC Address Association

   The requirements document [I-D.kreeger-nvo3-hypervisor-nve-cp] lists
   two approaches for acquiring VNIC address association information:

   1.  Data Plane Learning (i.e. - by inspecting source addresses in
       traffic received from an end device).

   2.  Explicit signaling from the end device when a specific VNIC
       address is to be associated with a tenant system.

     +----------------------+-------+-------+-------+-------+-------+
     | Supported Approaches | NVGRE | VxLAN |  VPLS |  EVPN | L3VPN |
     +----------------------+-------+-------+-------+-------+-------+
     | Data Plane Learning  |       |       |       |       |       |
     | - - -                | - - - | - - - | - - - | - - - | - - - |
     | Explicit Signaling   |       |       |       |       |       |
     +----------------------+-------+-------+-------+-------+-------+

                     Table 6: VNIC Address Association

   (4.3) VNIC Address Disassociation

   TBD

   (4.4) VNIC Shutdown/Startup/Migration

   TBD

   (4.5) VN Profile

   TBD



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6.  Data Plane Requirements

   In this section, numbering of requirement headings corresponds to
   section numbering in [I-D.ietf-nvo3-dataplane-requirements].

   (3.1) Virtual Access Points (VAPs)

   +------------------------+--------+-------+--------+--------+-------+
   | Requirement            | NVGRE  | VxLAN |  VPLS  |  EVPN  | L3VPN |
   +------------------------+--------+-------+--------+--------+-------+
   | MUST support VAP       |        |       |        |        |       |
   | identification         |        |       |        |        |       |
   | - - -                  | - - -  | - - - | - - -  | - - -  | - - - |
   | 1) Local interface     |  YES   |       |        |        |       |
   | - - -                  | - - -  | - - - | - - -  | - - -  | - - - |
   | 2) Local interface +   |  YES   |       |        |        |       |
   | fields in frame header |        |       |        |        |       |
   +------------------------+--------+-------+--------+--------+-------+

                 Table 7: VAP Identification Requirements

   (3.2) Virtual Network Instance (VNI)

   +-------------------------+-------+-------+--------+--------+-------+
   | Requirement             | NVGRE | VxLAN |  VPLS  |  EVPN  | L3VPN |
   +-------------------------+-------+-------+--------+--------+-------+
   | VAP are associated with |  YES  |       |        |        |       |
   | a specific VNI at       |       |       |        |        |       |
   | service instantiation   |       |       |        |        |       |
   | time.                   |       |       |        |        |       |
   +-------------------------+-------+-------+--------+--------+-------+

                       Table 8: VAP-VNI Association

   (3.2.1) L2 VNI

   +----------------------------+-------+-------+-------+------+-------+
   | Requirement                | NVGRE | VxLAN |  VPLS | EVPN | L3VPN |
   +----------------------------+-------+-------+-------+------+-------+
   | L2 VNI MUST provide an     |       |       |       |      |       |
   | emulated Ethernet          |       |       |       |      |       |
   | multipoint service as if   |       |       |       |      |       |
   | Tenant Systems are         |       |       |       |      |       |
   | interconnected by a bridge |       |       |       |      |       |
   | (but instead by using a    |       |       |       |      |       |
   | set of NVO3 tunnels).      |       |       |       |      |       |
   | - - -                      | - - - | - - - | - - - | - -  | - - - |
   |                            |       |       |       |  -   |       |



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   | Loop avoidance capability  |       |       |       |      |       |
   | MUST be provided.          |       |       |       |      |       |
   | - - -                      | - - - | - - - | - - - | - -  | - - - |
   |                            |       |       |       |  -   |       |
   | In the absence of a        |       |       |       |      |       |
   | management or control      |       |       |       |      |       |
   | plane, data plane learning |       |       |       |      |       |
   | MUST be used to populate   |       |       |       |      |       |
   | forwarding tables.         |       |       |       |      |       |
   | - - -                      | - - - | - - - | - - - | - -  | - - - |
   |                            |       |       |       |  -   |       |
   | When flooding is required, |       |       |       |      |       |
   | either to deliver unknown  |       |       |       |      |       |
   | unicast, or broadcast or   |       |       |       |      |       |
   | multicast traffic, the NVE |       |       |       |      |       |
   | MUST either support        |       |       |       |      |       |
   | ingress replication or     |       |       |       |      |       |
   | multicast.                 |       |       |       |      |       |
   | - - -                      | - - - | - - - | - - - | - -  | - - - |
   |                            |       |       |       |  -   |       |
   | In this latter case, the   |       |       |       |      |       |
   | NVE MUST be able to build  |       |       |       |      |       |
   | at least a default         |       |       |       |      |       |
   | flooding tree per VNI.     |       |       |       |      |       |
   +----------------------------+-------+-------+-------+------+-------+

                          Table 9: L2 VNI Service

   (3.2.2) L3 VNI

   +---------------------------+-------+-------+--------+------+-------+
   | Requirement               | NVGRE | VxLAN |  VPLS  | EVPN | L3VPN |
   +---------------------------+-------+-------+--------+------+-------+
   | L3 VNIs MUST provide      |       |       |        |      |       |
   | virtualized IP routing    |       |       |        |      |       |
   | and forwarding.           |       |       |        |      |       |
   | - - -                     | - - - | - - - | - - -  | - -  | - - - |
   |                           |       |       |        |  -   |       |
   | L3 VNIs MUST support per- |       |       |        |      |       |
   | tenant forwarding         |       |       |        |      |       |
   | instance with IP          |       |       |        |      |       |
   | addressing isolation and  |       |       |        |      |       |
   | L3 tunneling for          |       |       |        |      |       |
   | interconnecting instances |       |       |        |      |       |
   | of the same VNI on NVEs.  |       |       |        |      |       |
   +---------------------------+-------+-------+--------+------+-------+

                         Table 10: L3 VNI Service



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   (3.3.1) NVO3 overlay header

   +---------------------------+-------+-------+--------+------+-------+
   | Requirement               | NVGRE | VxLAN |  VPLS  | EVPN | L3VPN |
   +---------------------------+-------+-------+--------+------+-------+
   | An NVO3 overlay header    |  YES  |  YES  |  YES   | YES  |  YES  |
   | MUST be included after    |       |       |        |      |       |
   | the underlay tunnel       |       |       |        |      |       |
   | header when forwarding    |       |       |        |      |       |
   | tenant traffic.           |       |       |        |      |       |
   +---------------------------+-------+-------+--------+------+-------+

                         Table 11: Overlay Header

   (3.3.1.1) Virtual Network Context Identification

   +---------------------------+-------+-------+--------+------+-------+
   | Requirement               | NVGRE | VxLAN |  VPLS  | EVPN | L3VPN |
   +---------------------------+-------+-------+--------+------+-------+
   | The overlay encapsulation |  YES  |  YES  |  YES   | YES  |  YES  |
   | header MUST contain a     |       |       |        |      |       |
   | field which allows the    |       |       |        |      |       |
   | encapsulated frame to be  |       |       |        |      |       |
   | delivered to the          |       |       |        |      |       |
   | appropriate virtual       |       |       |        |      |       |
   | network endpoint by the   |       |       |        |      |       |
   | egress NVE.               |       |       |        |      |       |
   +---------------------------+-------+-------+--------+------+-------+

             Table 12: Virtual Network Context Identification

   (3.3.1.2) Service QoS identifier

   +----------------------------+-------+-------+-------+------+-------+
   | Requirement                | NVGRE | VxLAN |  VPLS | EVPN | L3VPN |
   +----------------------------+-------+-------+-------+------+-------+
   | Traffic flows originating  |   NO  |       |       |      |       |
   | from different             |       |       |       |      |       |
   | applications could rely on |       |       |       |      |       |
   | differentiated forwarding  |       |       |       |      |       |
   | treatment to meet end-to-  |       |       |       |      |       |
   | end availability and       |       |       |       |      |       |
   | performance objectives.    |       |       |       |      |       |
   +----------------------------+-------+-------+-------+------+-------+

                   Table 13: QoS Service Identification

   (3.3.2.1) LAG and ECMP



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   +-------------------------+-------+-------+--------+--------+-------+
   | Requirement             | NVGRE | VxLAN |  VPLS  |  EVPN  | L3VPN |
   +-------------------------+-------+-------+--------+--------+-------+
   | For performance         |  YES  |       |        |        |       |
   | reasons, multipath over |       |       |        |        |       |
   | LAG and ECMP paths      |       |       |        |        |       |
   | SHOULD be supported.    |       |       |        |        |       |
   +-------------------------+-------+-------+--------+--------+-------+

                        Table 14: Multipath Support

   (3.3.2.2) DiffServ and ECN marking

   +---------------------------+-------+-------+--------+------+-------+
   | Requirement               | NVGRE | VxLAN |  VPLS  | EVPN | L3VPN |
   +---------------------------+-------+-------+--------+------+-------+
   | [RFC2983] defines two     |   NO  |       |        |      |       |
   | modes for mapping the     |       |       |        |      |       |
   | DSCP markings from inner  |       |       |        |      |       |
   | to outer headers and vice |       |       |        |      |       |
   | versa. Both models SHOULD |       |       |        |      |       |
   | be supported.             |       |       |        |      |       |
   | - - -                     | - - - | - - - | - - -  | - -  | - - - |
   |                           |       |       |        |  -   |       |
   | ECN marking MUST be       |   NO  |       |        |      |       |
   | performed according to    |       |       |        |      |       |
   | [RFC6040] which describes |       |       |        |      |       |
   | the correct ECN behavior  |       |       |        |      |       |
   | for IP tunnels.           |       |       |        |      |       |
   +---------------------------+-------+-------+--------+------+-------+

                      Table 15: DSCP and ECN Marking

   (3.3.2.3) Handling of broadcast, unknown unicast, and multicast
   traffic

   +-----------------------------+-------+-------+------+------+-------+
   | Requirement                 | NVGRE | VxLAN | VPLS | EVPN | L3VPN |
   +-----------------------------+-------+-------+------+------+-------+
   | NVO3 data plane support for |  YES  |  YES  | YES  | YES  |  YES  |
   | either ingress replication  |       |       |      |      |       |
   | or point-to-multipoint      |       |       |      |      |       |
   | tunnels is required to send |       |       |      |      |       |
   | traffic destined to         |       |       |      |      |       |
   | multiple locations on a     |       |       |      |      |       |
   | per-VNI basis (e.g. L2/L3   |       |       |      |      |       |
   | multicast traffic, L2       |       |       |      |      |       |
   | broadcast and unknown       |       |       |      |      |       |



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   | unicast traffic).           |       |       |      |      |       |
   +-----------------------------+-------+-------+------+------+-------+

      Table 16: Handling of Broadcast, Unknown Unicast, and Multicast
                                  Traffic

   (3.4) External NVO3 connectivity

   +----------------------------+-------+-------+-------+------+-------+
   | Requirement                | NVGRE | VxLAN |  VPLS | EVPN | L3VPN |
   +----------------------------+-------+-------+-------+------+-------+
   | NVO3 services MUST         |  YES  |       |       |      |       |
   | interoperate with current  |       |       |       |      |       |
   | VPN and Internet services. |       |       |       |      |       |
   | This may happen inside one |       |       |       |      |       |
   | DC during a migration      |       |       |       |      |       |
   | phase or as NVO3 services  |       |       |       |      |       |
   | are delivered to the       |       |       |       |      |       |
   | outside world via Internet |       |       |       |      |       |
   | or VPN gateways.           |       |       |       |      |       |
   +----------------------------+-------+-------+-------+------+-------+

                         Table 17: Interoperation

   (3.5) Path MTU

   +--------------------------+-------+-------+--------+-------+-------+
   | Requirement              | NVGRE | VxLAN |  VPLS  |  EVPN | L3VPN |
   +--------------------------+-------+-------+--------+-------+-------+
   | Classical ICMP-based MTU |   NO  |       |        |       |       |
   | Path Discovery           |       |       |        |       |       |
   | ([RFC1191], [RFC1981])   |       |       |        |       |       |
   | or Extended MTU Path     |       |       |        |       |       |
   | Discovery techniques     |       |       |        |       |       |
   | such as defined in       |       |       |        |       |       |
   | [RFC4821].               |       |       |        |       |       |
   | - - -                    | - - - | - - - | - - -  | - - - | - - - |
   | Segmentation and         |  YES  |       |        |       |       |
   | reassembly support from  |       |       |        |       |       |
   | the overlay layer        |       |       |        |       |       |
   | operations without       |       |       |        |       |       |
   | relying on the Tenant    |       |       |        |       |       |
   | Systems to know about    |       |       |        |       |       |
   | the end-to-end MTU.      |       |       |        |       |       |
   +--------------------------+-------+-------+--------+-------+-------+

                            Table 18: Path MTU




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   (3.7) NVE Multi-Homing Requirements

   +--------------------------+-------+-------+--------+-------+-------+
   | Requirement              | NVGRE | VxLAN |  VPLS  |  EVPN | L3VPN |
   +--------------------------+-------+-------+--------+-------+-------+
   | Multi-homing techniques  |   NO  |       |        |       |       |
   | SHOULD be used to        |       |       |        |       |       |
   | increase the reliability |       |       |        |       |       |
   | of an NVO3 network.      |       |       |        |       |       |
   +--------------------------+-------+-------+--------+-------+-------+

                           Table 19: Multihoming

   (3.8) OAM

   +-----------------------------+-------+-------+------+------+-------+
   | Requirement                 | NVGRE | VxLAN | VPLS | EVPN | L3VPN |
   +-----------------------------+-------+-------+------+------+-------+
   | NVE MAY be able to          |   NO  |       |      |      |       |
   | originate/terminate OAM     |       |       |      |      |       |
   | messages for connectivity   |       |       |      |      |       |
   | verification, performance   |       |       |      |      |       |
   | monitoring, statistic       |       |       |      |      |       |
   | gathering and fault         |       |       |      |      |       |
   | isolation. Depending on     |       |       |      |      |       |
   | configuration, NVEs SHOULD  |       |       |      |      |       |
   | be able to process or       |       |       |      |      |       |
   | transparently tunnel OAM    |       |       |      |      |       |
   | messages, as well as        |       |       |      |      |       |
   | supporting alarm            |       |       |      |      |       |
   | propagation capabilities.   |       |       |      |      |       |
   +-----------------------------+-------+-------+------+------+-------+

                          Table 20: OAM Messaging

7.  Summary and Conclusions

   TBD

8.  Acknowledgements

   The Authors would like to acknowledge the technical contributions of
   Florin Balus, Luyuan Fang, Sue Hares, Wim Henderickx, Yuichi Ikejiri,
   Rangaraju Iyengar, Mircea Pisica, Evelyn Roch, Ali Sajassi, Peter
   Ashwood-Smith and Lucy Yong as well as the initial help in editing
   the XML source for the document from Tom Taylor.





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9.  IANA Considerations

   This memo includes no request to IANA.

10.  Security Considerations

   Security considerations of the requirements documents referenced by
   this analysis document apply.

11.  References

11.1.  Normative References

   [I-D.ashwood-nvo3-operational-requirement]
              Ashwood-Smith, P., Iyengar, R., Tsou, T., Sajassi, A.,
              Boucadair, M., Jacquenet, C., and M. Daikoku, "NVO3
              Operational Requirements", draft-ashwood-nvo3-operational-
              requirement-02 (work in progress), January 2013.

   [I-D.ietf-l2vpn-evpn]
              Sajassi, A., Aggarwal, R., Henderickx, W., Balus, F.,
              Isaac, A., and J. Uttaro, "BGP MPLS Based Ethernet VPN",
              draft-ietf-l2vpn-evpn-03 (work in progress), February
              2013.

   [I-D.ietf-nvo3-dataplane-requirements]
              Bitar, N., Lasserre, M., Balus, F., Morin, T., Jin, L.,
              and B. Khasnabish, "NVO3 Data Plane Requirements", draft-
              ietf-nvo3-dataplane-requirements-01 (work in progress),
              July 2013.

   [I-D.ietf-nvo3-framework]
              Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
              Rekhter, "Framework for DC Network Virtualization", draft-
              ietf-nvo3-framework-03 (work in progress), July 2013.

   [I-D.ietf-nvo3-overlay-problem-statement]
              Narten, T., Gray, E., Black, D., Fang, L., Kreeger, L.,
              and M. Napierala, "Problem Statement: Overlays for Network
              Virtualization", draft-ietf-nvo3-overlay-problem-
              statement-03 (work in progress), May 2013.

   [I-D.kreeger-nvo3-hypervisor-nve-cp]
              Kreeger, L., Narten, T., and D. Black, "Network
              Virtualization Hypervisor-to-NVE Overlay Control Protocol
              Requirements", draft-kreeger-nvo3-hypervisor-nve-cp-01
              (work in progress), February 2013.




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   [I-D.kreeger-nvo3-overlay-cp]
              Kreeger, L., Dutt, D., Narten, T., Black, D., and M.
              Sridharan, "Network Virtualization Overlay Control
              Protocol Requirements", draft-kreeger-nvo3-overlay-cp-04
              (work in progress), June 2013.

   [I-D.mahalingam-dutt-dcops-vxlan]
              Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "VXLAN: A
              Framework for Overlaying Virtualized Layer 2 Networks over
              Layer 3 Networks", draft-mahalingam-dutt-dcops-vxlan-04
              (work in progress), May 2013.

   [I-D.sridharan-virtualization-nvgre]
              Sridharan, M., Greenberg, A., Venkataramaiah, N., Wang,
              Y., Duda, K., Ganga, I., Lin, G., Pearson, M., Thaler, P.,
              and C. Tumuluri, "NVGRE: Network Virtualization using
              Generic Routing Encapsulation", draft-sridharan-
              virtualization-nvgre-02 (work in progress), February 2013.

   [RFC1191]  Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
              November 1990.

   [RFC1981]  McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
              for IP version 6", RFC 1981, August 1996.

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

   [RFC2983]  Black, D., "Differentiated Services and Tunnels", RFC
              2983, October 2000.

   [RFC4365]  Rosen, E., "Applicability Statement for BGP/MPLS IP
              Virtual Private Networks (VPNs)", RFC 4365, February 2006.

   [RFC4761]  Kompella, K. and Y. Rekhter, "Virtual Private LAN Service
              (VPLS) Using BGP for Auto-Discovery and Signaling", RFC
              4761, January 2007.

   [RFC4762]  Lasserre, M. and V. Kompella, "Virtual Private LAN Service
              (VPLS) Using Label Distribution Protocol (LDP) Signaling",
              RFC 4762, January 2007.

   [RFC4821]  Mathis, M. and J. Heffner, "Packetization Layer Path MTU
              Discovery", RFC 4821, March 2007.

   [RFC6040]  Briscoe, B., "Tunnelling of Explicit Congestion
              Notification", RFC 6040, November 2010.



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   [RFC6074]  Rosen, E., Davie, B., Radoaca, V., and W. Luo,
              "Provisioning, Auto-Discovery, and Signaling in Layer 2
              Virtual Private Networks (L2VPNs)", RFC 6074, January
              2011.

11.2.  Informative References

   [RFC3168]  Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
              of Explicit Congestion Notification (ECN) to IP", RFC
              3168, September 2001.

Authors' Addresses

   Eric Gray (editor)
   Ericsson
   120 Morris Avenue
   Pitman, New Jersey  08071
   USA

   Email: eric.gray@ericsson.com


   Nabil Bitar
   Verizon
   40 Sylvan Road
   Waltham, Massachusetts  02145
   USA

   Email: nabil.bitar@verizon.com


   Xiaoming Chen
   Huawei Technologies

   Email: ming.chen@huawei.com


   Marc Lasserre
   Alcatel-Lucent

   Email: marc.lasserre@alcatel-lucent.com










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   Tina Tsou
   Huawei Technologies (USA)
   2330 Central Expressway
   Santa Clara, California  95050
   USA

   Phone: +1 408 330 4424
   Email: Tina.Tsou.Zouting@huawei.com
   URI:   http://tinatsou.weebly.com/contact.html










































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