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

Versions: (draft-mglt-dots-use-cases) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20

DOTS                                                          R. Dobbins
Internet-Draft                                            Arbor Networks
Intended status: Informational                                D. Migault
Expires: September 29, 2018                                     Ericsson
                                                               S. Fouant

                                                            R. Moskowitz
                                                          HTT Consulting
                                                               N. Teague
                                                                Verisign
                                                                  L. Xia
                                                                  Huawei
                                                            K. Nishizuka
                                                      NTT Communications
                                                          March 28, 2018


                Use cases for DDoS Open Threat Signaling
                      draft-ietf-dots-use-cases-11

Abstract

   The DDoS Open Threat Signaling (DOTS) effort is intended to provide a
   protocol to facilitate interoperability across disparate DDoS
   mitigation solutions and services.  This document presents use cases
   which describe the interactions expected between the DOTS components
   as well as DOTS messaging exchanges.  The purpose of describing use
   cases is to identify the interacting DOTS components, how they
   collaborate and what are the types of information to be exchanged.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on September 29, 2018.





Dobbins, et al.        Expires September 29, 2018               [Page 1]


Internet-Draft               DOTS Use Cases                   March 2018


Copyright Notice

   Copyright (c) 2018 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
   (https://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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Acronyms  . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   3
     2.2.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Upstream DDoS Mitigation between an Enterprise Network
           and an Upstream Internet Transit Provider . . . . . . . .   4
     3.2.  DDoS Mitigation between an Enterprise Network and third
           party DDoS Mitigation Service Provider  . . . . . . . . .   7
     3.3.  DDoS Orchestration  . . . . . . . . . . . . . . . . . . .   9
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   At the time of writing, distributed denial-of-service (DDoS) attack
   mitigation solutions are largely based upon siloed, proprietary
   communications schemes with vendor lock-in as a side-effect.  This
   can result in the configuration, provisioning, operation, and
   activation of these solutions being a highly manual and often time-
   consuming process.  Additionally, coordination of multiple DDoS
   mitigation solutions simultaneously is fraught with both technical
   and process-related hurdles.  This greatly increases operational
   complexity which, in turn, can degrade the efficacy of mitigations.





Dobbins, et al.        Expires September 29, 2018               [Page 2]


Internet-Draft               DOTS Use Cases                   March 2018


   The DDoS Open Threat Signaling (DOTS) effort is intended to specify a
   protocol that facilitates interoperability between diverse DDoS
   mitigation solutions and ensures greater integration in term of
   mitigation requests and attack characterization patterns.  As DDoS
   solutions are broadly heterogeneous among vendors, the primary goal
   of DOTS is to provide high-level interaction amongst differing DDoS
   solutions, such as initiating, terminating DDoS mitigation assistance
   or requesting the status of a DDoS mitigation.

   This document provides use cases to provide inputs for the design of
   the DOTS protocol(s) as well as to illustrate the purpose of goals.
   The use cases are not exhaustive and future use cases are expected to
   emerge as DOTS is adopted and evolves.

2.  Terminology and Acronyms

2.1.  Requirements Terminology

   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].

2.2.  Acronyms

   This document makes use of the same terminology and definitions as
   [I-D.ietf-dots-requirements].  In addition it uses the terms defined
   below:

   o  DDoS Mitigation Service Provider: designates the administrative
      entity providing the DDoS Mitigation Service.

   o  DDoS Mitigation Service: designates a service provides to a
      customer.  Services usually involves Service Level Agreement (SLA)
      that have to be met.  It is the responsibility of the service
      provider to instantiate the DDoS Mitigation System to meet these
      SLA.

   o  DDoS Mitigation System (DMS): A system that performs DDoS
      mitigation.  The DDoS Mitigation System may be composed by a
      cluster of hardware and/or software resources, but could also
      involve an orchestrator that may take decisions such as
      outsourcing partial or more of the mitigation to another DDoS
      Mitigation System.

   o  DDoS Mitigation: The action performed by the DDoS Mitigation
      System.

   o  Internet Transit Provider (ITP):



Dobbins, et al.        Expires September 29, 2018               [Page 3]


Internet-Draft               DOTS Use Cases                   March 2018


3.  Use Cases

3.1.  Upstream DDoS Mitigation between an Enterprise Network and an
      Upstream Internet Transit Provider

   This use case describes how an enterprise network may take advantage
   of a pre-existing relation with its Internet Transit Provider (ITP)
   in order to mitigate a DDoS attack targeting its network.  As the ITP
   provides connectivity to the enterprise network, it is already on the
   path of the inbound or outbound traffic of the enterprise network and
   well aware of the networking parameters associated to the enterprise
   network connectivity.  This eases both the configuration and the
   instantiation of a DDoS Mitigation Service.  This section considers
   two kind of DDoS Mitigation Service between an enterprise network and
   an ITP:

   o  The upstream ITP may instantiate a DDoS Mitigation System (DMS)
      upon receiving a request from the enterprise network.  This
      typically corresponds to the case when the enterprise network is
      under attack.

   o  On the other hand, the ITP may identify an enterprise network as
      the source of an attack and send a mitigation request for the
      enterprise to mitigate this at the source.

   In the first scenario, as depicted in Figure 1, an enterprise network
   with self-hosted Internet-facing properties such as Web servers,
   authoritative DNS servers, and VoIP PBXes has a DMS deployed to
   protect those servers and applications from DDoS attacks.  In
   addition to their on-premise DDoS defense capability, they have
   contracted with their Internet transit provider for DDoS Mitigation
   Services which threaten to overwhelm their transit link bandwidth.



















Dobbins, et al.        Expires September 29, 2018               [Page 4]


Internet-Draft               DOTS Use Cases                   March 2018


       +------------------+        +------------------+
       | Entreprise       |        | Upstream         |
       | Network          |        | Internet Transit |
       |                  |        | Provider         |
       |      +--------+  |        |             DDoS Attack
       |      | DDoS   |  | <=================================
       |      | Target |  | <=================================
       |      +--------+  |        |  +------------+  |
       |                  | +-------->| DDoS       |  |
       |                  | |      |S | Mitigation |  |
       |                  | |      |  | System     |  |
       |                  | |      |  +------------+  |
       |                  | |      |                  |
       |                  | |      |                  |
       |  +------------+  | |      |                  |
       |  | DDoS       |<---+      |                  |
       |  | Mitigation |C |        |                  |
       |  | System     |  |        |                  |
       |  +------------+  |        |                  |
       +------------------+        +------------------+

          * C is for DOTS Client functionality
          * S is for DOTS Server functionality

       Figure 1: Upstream Internet Transit Provider DDoS Mitigation

   The enterprise DMS is configured such that if the incoming Internet
   traffic volume exceeds 50% of the provisioned upstream Internet
   transit link capacity, the DMS will request DDoS mitigation
   assistance from the upstream transit provider.

   The requests to trigger, manage, and finalize a DDoS Mitigation
   between the enterprise DMS and the ITP is performed using DOTS.  The
   enterprise DMS implements a DOTS Client while the ITP implements a
   DOTS Server which is integrated with their DMS.

   When the enterprise DMS detects an inbound DDoS attack targeting its
   servers and applications, it immediately begins a DDoS Mitigation.

   During the course of the attack, the inbound traffic volume exceeds
   the 50% threshold; the DMS DOTS Client signals the DOTS Server on the
   upstream ITP to initiate DDoS Mitigation.  The DOTS Server signals
   the DOTS Client that it can serve this request, and mitigation is
   initiated on the ITP network by the DMS.

   Over the course of the attack, the DOTS Server of the ITP
   periodically informs the DOTS Client on the enterprise DMS mitigation
   status, statistics related to DDoS attack traffic mitigation, and



Dobbins, et al.        Expires September 29, 2018               [Page 5]


Internet-Draft               DOTS Use Cases                   March 2018


   related information.  Once the DDoS attack has ended, the DOTS Server
   signals the enterprise DMS DOTS Client that the attack has subsided.

   The enterprise DMS then requests the ITP to terminate the DDoS
   Mitigation.  The DOTS Server on the ITP receives this request and
   once the mitigation has ended, confirms the end of upstream DDoS
   Mitigation to the enterprise DMS DOTS Client.

   The following is an overview of the DOTS communication model for this
   use-case:

   o  (a) A DDoS attack is initiated against online properties of an
      network organization which has deployed a DOTS-Client-capable DMS.

   o  (b) The DMS detects, classifies, and begins the DDoS Mitigation.

   o  (c) The DMS determines that its capacity and/or capability to
      mitigate the DDoS attack is insufficient, and sends via its DOTS
      Client a DOTS DDoS Mitigation request to one or more DOTS Servers
      residing on the upstream ITP.

   o  (d) The DOTS Server which receive the DOTS Mitigation request
      determines that they have been configured to honor requests from
      the requesting DOTS Client, and honored its DDoS Mitigation by
      orchestrating its DMS.

   o  (e) While the DDoS Mitigation is active, the DOTS Servers
      regularly transmit DOTS DDoS Mitigation status updates to the DOTS
      Client.

   o  (f) The DOTS Client transmits a DOTS DDoS Mitigation termination
      request to the DOTS Server.

   o  (g) The DOTS Server terminates DDoS Mitigation.

   Note that communications between the enterprise DOTS Client and the
   upstream transit provider DOTS Server may take place in-band within
   the main Internet transit link between the enterprise and the ITP;
   out-of-band via a separate, dedicated wireline network link utilized
   solely for DOTS signaling; or out-of-band via some other form of
   network connectivity such as a third-party wireless 4G network link.

   Note also that the DOTS Clients that sends the DOTS Mitigation
   request may be also triggered by a network admin that manually
   confirms the request to the upstream ITP, in which case the request
   my be sent from an application such as a web browser in a mobile
   phone.




Dobbins, et al.        Expires September 29, 2018               [Page 6]


Internet-Draft               DOTS Use Cases                   March 2018


   Note also that when the enterprise is multihomed and connected to
   multiple upstream ITP, each ITP is only able to provide a DDoS
   Mitigation Service for the traffic it transits.  As a result, the
   enterprise network may require to coordinate the various DDoS
   Mitigation Services associated to each link.

   The current scenario describes the case where the DDoS Target is in
   the enterprise network while the DMS is provided by the upstream ITP.
   An alternate use case may consider the case where the ITP informs the
   enterprise network it is involved into an ongoing attack or that
   infected machines have been identified.  In this case the DOTS Client
   and DOTS Server roles are inverted.  The DOTS Client is located in
   the ITP network and the DOTS Server is hosted in the enterprise
   network.  The enterprise network is then responsible to perform the
   DDoS Mitigation.  In some case the DDoS Mitigation may be delegated
   back to the upstream ITP, as described in this section.

3.2.  DDoS Mitigation between an Enterprise Network and third party DDoS
      Mitigation Service Provider

   This use case differs from the previous use case in that the DDoS
   Mitigation Service is not provided by an upstream ITP.  In other
   words, as represented in figure 2, the traffic does not not go
   through the DDoS Mitigation Service Provider by default.  In order to
   steer the traffic to the DDoS Mitigation Service Provider, some
   network configuration are required.  As such it may be reserved for
   large enterprises or large data centers.

   We follow the terminology of section Section 3.1, however the
   Enterprise Network is not limited to the network hosting the DDoS
   Target.  In fact, it could also be a DDoS Mitigation Service Provider
   that has reached it resources capacities and delegate the DDoS
   Mitigation to other DDoS Mitigation Service Providers, thus forming
   an overlay of DMS.

















Dobbins, et al.        Expires September 29, 2018               [Page 7]


Internet-Draft               DOTS Use Cases                   March 2018


      +------------------+        +------------------+
      | Entreprise       |        | Upstream         |
      | Network          |        | Internet Transit |
      |                  |        | Provider         |
      |      +--------+  |        |             DDoS Attack
      |      | DDoS   |  | <=================================
      |      | Target |  | <=================================
      |      +--------+  |        |                  |
      |                  |        +------------------+
      |                  |
      |                  |        +------------------+
      |                  |        | DDoS Mitigation  |
      |                  |        | Service Provider |
      |                  |        |                  |
      |  +------------+  |        |  +------------+  |
      |  | DDoS       |<------------>| DDoS       |  |
      |  | Mitigation |C |        | S| Mitigation |  |
      |  | System     |  |        |  | System     |  |
      |  +------------+  |        |  +------------+  |
      +------------------+        +------------------+

          * C is for DOTS Client functionality
          * S is for DOTS Server functionality

      Figure 2: DDoS Mitigation between an Enterprise Network and third
                party DDoS Mitigation Service Provider

   In this scenario, an Enterprise Network has entered into a pre-
   arranged DDoS mitigation assistance agreement with one or more other
   DDoS Mitigation Service Providers in order to ensure that sufficient
   DDoS mitigation capacity and/or capabilities may be activated in the
   event that a given DDoS attack threatens to overwhelm the ability of
   a given DMS to mitigate the attack on its own.

   The pre-arrangement typically includes the agreement on the
   mechanisms used to redirect the traffic to the DDoS Mitigation
   Service Provider, as well as the mechanism to to re-inject the
   traffic back to the Enterprise Network.  Redirection to the DDoS
   Mitigation Service Provider typically involves BGP prefix
   announcement eventually combined with DNS redirection, while re-
   injection may be performed via tunneling mechanisms such as GRE for
   example.  Of course, such mechanisms needs to be regularly tested and
   evaluated.








Dobbins, et al.        Expires September 29, 2018               [Page 8]


Internet-Draft               DOTS Use Cases                   March 2018


     +------------------+        +------------------+
     | Entreprise       |        | Upstream         |
     | Network          |        | Internet Transit |
     |                  |        | Provider         |
     |      +--------+  |        |             DDoS Attack
     |      | DDoS   |  |<----------------+         | ++====
     |      | Target |  |        |        |         | || ++=
     |      +--------+  |        |        |         | || ||
     |                  |        +--------|---------+ || ||
     |                  |                 |           || ||
     |                  |        +--------|---------+ || ||
     |                  |        | DDoS Mitigation  | || ||
     |                  |        | Service Provider | || ||
     |                  |        |        |         | || ||
     |  +------------+  |        |  +------------+  | || ||
     |  | DDoS       |<------------>| DDoS       |  | || ||
     |  | mitigation |C |        |S | mitigation |<===++ ||
     |  | system     |  |        |  | system     |<======++
     |  +------------+  |        |  +------------+  |
     +------------------+        +------------------+

          * C is for DOTS Client functionality
          * S is for DOTS Server functionality

     Figure 3: Redirection to a DDoS Mitigation Service Provider

   When the Enterprise Network is under attack or at least is reaching
   its capacity or ability to mitigate a given DDoS attack traffic, the
   DOTS Client sends a DOTS request to the DDoS Mitigation Service
   Provider to initiate network traffic diversion - as represented in
   figure 3 - and DDoS mitigation activities.  Ongoing attack and
   mitigation status messages may be passed between the Enterprise
   Network and the DDoS Mitigation Service Provider.

   Once the requesting Enterprise Network is confident that the DDoS
   attack has either ceased or has fallen to levels of traffic/
   complexity which they can handle on their own or that it has received
   a DOTS DDoS Mitigation termination request from a downstream
   Enterprise Network or DDoS Mitigation Service Provider, the
   requesting Enterprise Network DOTS Client sends a DOTS DDoS
   Mitigation termination requests to the DDoS Mitigation Service
   Provider.

3.3.  DDoS Orchestration

   In this use case, one or more DDoS telemetry systems or monitoring
   devices such as a flow telemetry collector monitor a network -
   typically an ISP network.  Upon detection of a DDoS attack, these



Dobbins, et al.        Expires September 29, 2018               [Page 9]


Internet-Draft               DOTS Use Cases                   March 2018


   telemetry systems alert an orchestrator in charge of coordinating the
   various DMS within the domain.  The telemetry systems may be
   configured to provide necessary and useful pieces of information,
   such as a preliminary analysis of the observation to the
   orchestrator.

   The orchestrator analyses the various information it receives from
   specialized equipements, and elaborates one or multiple DDoS
   mitigation strategies.  In some case, a manual confirmation may also
   be required to choose a proposed strategy or to initiate a DDoS
   Mitigation.  The DDoS Mitigation may consist of multiple steps such
   as configuring the network, various hardware, or updating already
   instantiated DDoS mitigation functions.  In some cases, some specific
   virtual DDoS mitigation functions must be instantiated and properly
   ordered.  Eventually, the coordination of the mitigation may involve
   external DDoS resources such as a transit provider or a DDoS
   Mitigation Service Provider.

   The communications used to trigger a DDoS Mitigation between the
   telemetry and monitoring systems and the orchestrator is performed
   using DOTS.  The telemetry systems implements a DOTS Client while the
   orchestrator implements a DOTS Server.

   The communication between a network administrator and the
   orchestrator is also performed using DOTS.  The network administrator
   via its web interfaces implements a DOTS Client, while the
   Orchestrator implements a DOTS Server.

   The communication between the Orchestrator and the DDoS mitigation
   systems is performed using DOTS.  The Orchestrator implements a DOTS
   Client while the DDoS mitigation systems implement a DOTS Server.

   The configuration aspects of each DDoS mitigation system, as well as
   the instantiations of DDoS mitigation functions or network
   configuration is not part of DOTS.  Similarly, the discovery of
   available DDoS mitigation functions is not part of DOTS.















Dobbins, et al.        Expires September 29, 2018              [Page 10]


Internet-Draft               DOTS Use Cases                   March 2018


          +----------+
          | network  |C
          | adminis  |<-+
          | trator   |  |
          +----------+  |
                        |                       (internal)
          +----------+  | S+--------------+     +-----------+
          |telemetry/|  +->|              |C   S| DDoS      |+
          |monitoring|<--->| Orchestrator |<--->| mitigation||
          |systems   |C   S|              |<-+  | systems   ||
          +----------+     +--------------+C |  +-----------+|
                                             |    +----------+
                                             |
                                             |  (external)
                                             |  +-----------+
                                             | S| DDoS      |
                                             +->| mitigation|
                                                | systems   |
                                                +-----------+
          * C is for DOTS Client functionality
          * S is for DOTS Server functionality

   Figure 4: DDoS Orchestration

   The telemetry systems monitor various traffic network and perform
   their measurement tasks.  They are configured so that when an event
   or some measurements reach a predefined level to report a DOTS
   mitigation request to the Orchestrator.  The DOTS mitigation request
   may be associated with some element such as specific reporting.

   Upon receipt of the DOTS mitigation request from the telemetry
   system, the Orchestrator responds with an acknowledgment, to avoid
   retransmission of the request for mitigation.  The status of the DDoS
   mitigation indicates the Orchestrator is in an analyzing phase.  The
   Orchestrator begins collecting various information from various
   telemetry systems in order to correlate the measurements and provide
   an analysis of the event.  Eventually, the Orchestrator may ask
   additional information to the telemetry system, however, the
   collection of these information is performed outside DOTS.

   The orchestrator may be configured to start a DDoS Mitigation upon
   approval from a network administrator.  The analysis from the
   orchestrator is reported to the network administrator via a web
   interface.  If the network administrator decides to start the
   mitigation, she orders through her web interface a DOTS Client to
   send a request for DDoS mitigation.  This request is expected to be
   associated with a context that identifies the DDoS mitigation
   selected.



Dobbins, et al.        Expires September 29, 2018              [Page 11]


Internet-Draft               DOTS Use Cases                   March 2018


   Upon receiving the DOTS request for DDoS mitigation from the network
   administrator, the orchestrator orchestrates the DDoS mitigation
   according to the specified strategy.  Its status indicates the DDoS
   mitigation is starting while not effective.

   Orchestration of the DDoS mitigation systems works similarly as
   described in Section XXX.  The Orchestrator indicates with its status
   whether the DDoS Mitigation is effective.

   When the DDoS mitigation is finished on the DDoS mitigation systems,
   the orchestrator indicates to the Telemetry systems as well as to the
   network administrator the DDoS mitigation is finished.

4.  Security Considerations

   DOTS is at risk from three primary attacks: DOTS agent impersonation,
   traffic injection, and signaling blocking.  The DOTS protocol MUST be
   designed for minimal data transfer to address the blocking risk.

   Impersonation and traffic injection mitigation can be managed through
   current secure communications best practices.  DOTS is not subject to
   anything new in this area.  One consideration could be to minimize
   the security technologies in use at any one time.  The more needed,
   the greater the risk of failures coming from assumptions on one
   technology providing protection that it does not in the presence of
   another technology.

   Additional details of DOTS security requirements may be found in
   [I-D.ietf-dots-requirements].

5.  IANA Considerations

   No IANA considerations exist for this document at this time.

6.  Acknowledgments

   The authors would like to thank among others Tirumaleswar Reddy;
   Andrew Mortensen; Mohamed Boucadaire; Artyom Gavrichenkov; and the
   DOTS WG chairs, Roman D.  Danyliw and Tobias Gondrom, for their
   valuable feedback.

7.  References

7.1.  Normative References







Dobbins, et al.        Expires September 29, 2018              [Page 12]


Internet-Draft               DOTS Use Cases                   March 2018


   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

7.2.  Informative References

   [I-D.ietf-dots-requirements]
              Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed
              Denial of Service (DDoS) Open Threat Signaling
              Requirements", draft-ietf-dots-requirements-14 (work in
              progress), February 2018.

Authors' Addresses

   Roland Dobbins
   Arbor Networks
   Singapore

   EMail: rdobbins@arbor.net


   Daniel Migault
   Ericsson
   8275 Trans Canada Route
   Saint Laurent, QC  4S 0B6
   Canada

   EMail: daniel.migault@ericsson.com


   Stefan Fouant
   USA

   EMail: stefan.fouant@copperriverit.com


   Robert Moskowitz
   HTT Consulting
   Oak Park, MI  48237
   USA

   EMail: rgm@labs.htt-consult.com








Dobbins, et al.        Expires September 29, 2018              [Page 13]


Internet-Draft               DOTS Use Cases                   March 2018


   Nik Teague
   Verisign
   12061 Bluemont Way
   Reston, VA  20190

   EMail: nteague@verisign.com


   Liang Xia
   Huawei
   No. 101, Software Avenue, Yuhuatai District
   Nanjing
   China

   EMail: Frank.xialiang@huawei.com


   Kaname Nishizuka
   NTT Communications
   GranPark 16F 3-4-1 Shibaura, Minato-ku
   Tokyo  108-8118
   Japan

   EMail: kaname@nttv6.jp



























Dobbins, et al.        Expires September 29, 2018              [Page 14]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/