PCEP Extension for L2 Flow Specification
draft-ietf-pce-pcep-l2-flowspec-03

PCE Working Group                                               D. Dhody
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                               A. Farrel
Expires: 7 July 2023                                  Old Dog Consulting
                                                                   Z. Li
                                                     Huawei Technologies
                                                          3 January 2023

                PCEP Extension for L2 Flow Specification
                   draft-ietf-pce-pcep-l2-flowspec-03

Abstract

   The Path Computation Element (PCE) is a functional component capable
   of selecting paths through a traffic engineering (TE) network.  These
   paths may be supplied in response to requests for computation or may
   be unsolicited requests issued by the PCE to network elements.  Both
   approaches use the PCE Communication Protocol (PCEP) to convey the
   details of the computed path.

   Traffic flows may be categorized and described using "Flow
   Specifications".  RFC 8955 defines the Flow Specification and
   describes how Flow Specification components are used to describe
   traffic flows.  RFC 8955 also defines how Flow Specifications may be
   distributed in BGP to allow specific traffic flows to be associated
   with routes.

   RFC 9168 specifies a set of extensions to PCEP to support the
   dissemination of Flow Specifications.  This allows a PCE to indicate
   what traffic should be placed on each path that it is aware of.

   The extensions defined in this document extend the support for
   Ethernet Layer 2 (L2) and Layer 2 Virtual Private Network (L2VPN)
   traffic filtering rules either by themselves or in conjunction with
   L3 flowspecs.

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/.

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   Internet-Drafts are draft documents valid for a maximum of six months
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  L2 Flow Specifications  . . . . . . . . . . . . . . . . . . .   5
     3.1.  L2 Flow Specification TLVs  . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  PCEP TLV Type Indicators  . . . . . . . . . . . . . . . .   7
     4.2.  L2 Flow Specification TLV Type Indicators . . . . . . . .   7
   5.  Implementation Status . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  Manageability Considerations  . . . . . . . . . . . . . . . .   9
     7.1.  Control of Function and Policy  . . . . . . . . . . . . .   9
     7.2.  Information and Data Models . . . . . . . . . . . . . . .   9
     7.3.  Liveness Detection and Monitoring . . . . . . . . . . . .   9
     7.4.  Verify Correct Operations . . . . . . . . . . . . . . . .   9
     7.5.  Requirements On Other Protocols . . . . . . . . . . . . .   9
     7.6.  Impact On Network Operations  . . . . . . . . . . . . . .  10
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Contributors . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

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1.  Introduction

   [RFC4655] defines the Path Computation Element (PCE), as a functional
   component capable of computing paths for use in traffic engineering
   networks.  PCE was originally conceived for use in Multiprotocol
   Label Switching (MPLS) for traffic engineering (TE) networks to
   derive the routes of Label Switched Paths (LSPs).  However, the scope
   of PCE was quickly extended to make it applicable to networks
   controlled by Generalized MPLS (GMPLS), and more recent work has
   brought other traffic engineering technologies and planning
   applications into scope (for example, Segment Routing (SR)
   [RFC8664]).

   [RFC5440] describes the PCE Communication Protocol (PCEP).  PCEP
   defines the communication between a Path Computation Client (PCC) and
   a PCE, or between PCE and PCE, enabling computation of the path for
   MPLS-TE LSPs.

   Stateful PCE [RFC8231] specifies a set of extensions to PCEP to
   enable control of TE-LSPs by a PCE that retains the state of the LSPs
   provisioned in the network (a stateful PCE).  [RFC8281] describes the
   setup, maintenance, and teardown of LSPs initiated by a stateful PCE
   without the need for local configuration on the PCC, thus allowing
   for a dynamic network that is centrally controlled.  [RFC8283]
   introduces the architecture for PCE as a central controller and
   describes how PCE can be viewed as a component that performs
   computation to place "flows" within the network and decide how these
   flows are routed.

   The description of traffic flows by the combination of multiple Flow
   Specification components and their dissemination as traffic flow
   specifications (Flow Specifications) is described for BGP in
   [RFC8955].  In BGP, a Flow Specification is comprised of traffic
   filtering rules and is associated with actions to perform on the
   packets that match the Flow Specification.  The BGP routers that
   receive a Flow Specification can classify received packets according
   to the traffic filtering rules and can direct packets based on the
   associated actions.  [I-D.ietf-idr-flowspec-v2] specify version 2 of
   the BGP flow specification protocol that resolves some of the issues
   with version 1.

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   When a PCE is used to initiate tunnels (such as TE-LSPs or SR paths)
   using PCEP, it is important that the head end of the tunnels
   understands what traffic to place on each tunnel.  The data flows
   intended for a tunnel can be described using Flow Specification
   components.  When PCEP is in use for tunnel initiation it makes sense
   for that same protocol to be used to distribute the Flow
   Specification components that describe what data is to flow on those
   tunnels.

   [RFC9168] specifies a set of extensions to PCEP to support the
   dissemination of Flow Specification components.  It includes the
   creation, update, and withdrawal of Flow Specifications via PCEP, and
   can be applied to tunnels initiated by the PCE or to tunnels where
   control is delegated to the PCE by the PCC.  Furthermore, a PCC
   requesting a new path can include Flow Specifications in the request
   to indicate the purpose of the tunnel allowing the PCE to factor this
   into the path computation.

   [I-D.ietf-idr-flowspec-l2vpn] defines a BGP flowspec extension to
   disseminate Ethernet Layer 2 (L2) and Layer 2 Virtual Private Network
   (L2VPN) traffic filtering rules either by themselves or in
   conjunction with L3 flowspecs as per [I-D.ietf-idr-flowspec-v2].
   This document extends the same support for PCEP by defining a new L2
   Flow Filter TLV to be carried within the FLOWSPEC object.  The
   context and the procedures for the use of Flow Specifications are as
   per [RFC9168].

2.  Terminology

   This document uses the following terms defined in [RFC5440]: PCC,
   PCE, PCEP Peer.

   The following term from [RFC8955] is used frequently throughout this
   document:

      A Flow Specification is an n-tuple consisting of several matching
      criteria that can be applied to IP traffic.  A given IP packet is
      said to match the defined Flow Specification if it matches all the
      specified criteria.

   Its usage in PCEP is further clarified in [RFC9168].

   This document uses the terms "stateful PCE" and "active PCE" as
   advocated in [RFC7399].

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   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  L2 Flow Specifications

   As per [RFC9168], to carry Flow Specifications in PCEP messages, a
   PCEP object called the PCEP FLOWSPEC object is defined.  To describe
   a traffic flow, a PCEP TLV called the Flow Filter TLV is also
   defined.  This document extends the support for L2 flow
   specifications by creating a new PCEP TLV called L2 Flow Filter TLV
   and update the processing rules.

   The PCEP FLOWSPEC object carries a FlowSpec filter rule encoded in a
   TLV.  To describe a traffic flow based on both L3 and L2 fields a new
   L2 Flow Filter TLV is introduced by this document.  The PCEP FLOWSPEC
   object could carries one of the following combinations of TLVs:

   *  no TLV

   *  one Flow Filter TLV

   *  one L2 Flow Filter TLV

   *  both a Flow Filter TLV and an L2 Flow Filter TLV

   At most one L2 Flow Filter TLV MAY be include in the the PCEP
   FLOWSPEC object.  The TLV is OPTIONAL when the R (remove) bit is set
   in the object.  At least one Flow Filter TLV or one L2 Flow Filter
   TLV MUST be present when the R bit is clear.  If both TLVs are
   missing when the R bit is clear, the PCEP peer MUST respond with a
   PCErr message with error-type TBD1 (FlowSpec Error) and error-value 2
   (Malformed FlowSpec).  A Flow Filter TLV and a L2 Flow Filter TLV MAY
   both be present when filtering is based on both L3 and L2 fields.

   The TLV follow the format of all PCEP TLVs as defined in [RFC5440].
   The Type field values come from the codepoint space for PCEP TLVs and
   has the value TBD2.  The value field of L2 Flow Filter TLV contain
   one or more sub-TLVs (Section 3.1, and they represent the complete
   definition of a Flow Specification for traffic to be placed on the
   tunnel.  The set of Flow Specification TLVs and L2 Flow Filter TLVs
   in a single instance of a Flow Filter TLV are combined to indicate
   the specific Flow Specification.  Note that the PCEP FLOWSPEC object
   can include just one Flow Filter TLV, just one L2 Flow Filter TLV, or
   one of each TLV.

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   The rest of the procedures are same as [RFC9168].

3.1.  L2 Flow Specification TLVs

   The L2 Flow Filter TLV carries one or more L2 Flow Specification TLV.
   The L2 Flow Specification TLV follows the format of all PCEP TLVs as
   defined in [RFC5440].  However, the Type values are selected from a
   separate IANA registry (see Section 4.2) rather than from the common
   PCEP TLV registry.

   Type values are chosen so that there can be commonality with L2 Flow
   Specifications defined for use with BGP
   [I-D.ietf-idr-flowspec-l2vpn].  This is possible because the BGP Flow
   Spec encoding uses a single octet to encode the type where as PCEP
   uses two octets.  Thus the space of values for the Type field is
   partitioned as shown in Figure 1.

      Range          |
      ---------------+-------------------------------------------------
      0 .. 255       | Per BGP registry defined by
                     | [I-D.ietf-idr-flowspec-l2vpn].
                     | Not to be allocated in this registry.
                     |
      256 ..   65535 | New PCEP Flow Specifications allocated according
                     | to the registry defined in this document.

              Figure 1: L2 Flow Specification TLV Type Ranges

   [I-D.ietf-idr-flowspec-l2vpn] is the reference for the registry "L2
   Flow Spec Component Types" and defines the allocations it contains.

   The content of the Value field in each TLV is specific to the type
   and describes the parameters of the Flow Specification.  The
   definition of the format of many of these Value fields is inherited
   from BGP specifications.  Specifically, the inheritance is from
   [I-D.ietf-idr-flowspec-l2vpn], but may also be inherited from future
   BGP specifications.

   When multiple L2 Flow Specification TLVs are present in a single L2
   Flow Filter TLV they are combined to produce a more detailed
   specification of a flow.  Similarly, when both Flow Filter TLV and L2
   Flow Filter TLV are present, they are combined to produce a more
   detailed specification of a flow.

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   An implementation that receives a PCEP message carrying a L2 Flow
   Specification TLV with a type value that it does not recognize or
   does not support MUST respond with a PCErr message with error-type
   TBD1 (FlowSpec Error), error-value 1 (Unsupported FlowSpec) and MUST
   NOT install the Flow Specification.

   All L2 Flow Specification TLVs with Types in the range 0 to 255 have
   their Values interpreted as defined for use in BGP (for example, in
   [I-D.ietf-idr-flowspec-l2vpn]) and are set using the BGP encoding,
   but without the type octet (the relevant information is in the Type
   field of the TLV).  The Value field is padded with trailing zeros to
   achieve 4-byte alignment.

   This document defines no new types.

4.  IANA Considerations

   IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
   registry.  This document requests IANA actions to allocate code
   points for the protocol elements defined in this document.

4.1.  PCEP TLV Type Indicators

   IANA maintains a subregistry called "PCEP TLV Type Indicators".  IANA
   is requested to make an assignment from this subregistry as follows:

   Value   | Meaning                      | Reference
   --------+------------------------------+-------------
    TBD2   | L2 FLOW FILTER TLV           | [This.I-D]

4.2.  L2 Flow Specification TLV Type Indicators

   IANA is requested to create a new subregistry called the "PCEP L2
   Flow Specification TLV Type Indicators" registry.

   Allocations from this registry are to be made according to the
   following assignment policies [RFC8126]:

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    Range          | Assignment policy
    ---------------+---------------------------------------------------
    0 .. 255       | Reserved - must not be allocated.
                   | Usage mirrors the BGP L2 FlowSpec registry
                   | [I-D.ietf-idr-flowspec-l2vpn].
                   |
    256 ..   64506 | Specification Required
                   |
    64507 .. 65531 | First Come First Served
                   |
    65532 .. 65535 | Experimental

   This documents make no allocations in the newly created registry.

5.  Implementation Status

   [NOTE TO RFC EDITOR : This whole section and the reference to RFC
   7942 is to be removed before publication as an RFC]

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in [RFC7942].
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   According to [RFC7942], "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.
   It is up to the individual working groups to use this information as
   they see fit".

   At the time of posting the -03 version of this document, there are no
   known implementations of this mechanism.  It is believed that some
   vendor are considering prototype implementations, but these plans are
   too vague to make any further assertions.

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6.  Security Considerations

   We may assume that a system that utilizes a remote PCE is subject to
   a number of vulnerabilities that could allow spurious LSPs or SR
   paths to be established or that could result in existing paths being
   modified or torn down.  Such systems, therefore, apply security
   considerations as described in [RFC5440], Section 2.5 of [RFC6952],
   [RFC8253], and [RFC8955].

   As per [RFC9168], the description of Flow Specifications associated
   with paths set up or controlled by a PCE add a further detail that
   could be attacked without tearing down LSPs or SR paths, but causing
   traffic to be misrouted within the network.  Therefore, the use of
   the security mechanisms for PCEP referenced above is important.  It
   further list the security considerations with respect to flow
   specifications which are applicable to L2 flowspec as well.

7.  Manageability Considerations

7.1.  Control of Function and Policy

   [RFC9168] describe the management of multiple flowspecs as well as
   control via configurations and policies.  This is applicable to the
   L2 flowspec defined in this document.

7.2.  Information and Data Models

   As per [RFC9168], the PCEP YANG module [I-D.ietf-pce-pcep-yang] would
   need to be augmented to cover flowspec include L2.

7.3.  Liveness Detection and Monitoring

   Mechanisms defined in this document do not imply any new liveness
   detection and monitoring requirements in addition to those already
   listed in [RFC5440].

7.4.  Verify Correct Operations

   Mechanisms defined in this document do not imply any new operation
   verification requirements in addition to those already listed in
   [RFC9168].

7.5.  Requirements On Other Protocols

   Mechanisms defined in this document do not imply any new requirements
   on other protocols.

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7.6.  Impact On Network Operations

   The use of the features described in this document clearly have an
   important impact on network traffic since they cause traffic to be
   routed on specific paths in the network.  However, in practice, these
   changes make no direct changes to the network operation because
   traffic is already placed on those paths using some pre-existing
   configuration mechanism.  Thus, the significant change is the
   reduction in mechanisms that have to be applied rather than a change
   to how the traffic is passed through the network.

8.  Acknowledgements

   Thanks to Susan Hares for discussion related to BGP Flowspec V2.

9.  References

9.1.  Normative References

   [I-D.ietf-idr-flowspec-l2vpn]
              Weiguo, H., Eastlake, D. E., Litkowski, S., and S. Zhuang,
              "BGP Dissemination of L2 Flow Specification Rules", Work
              in Progress, Internet-Draft, draft-ietf-idr-flowspec-
              l2vpn-20, 9 October 2022,
              <https://www.ietf.org/archive/id/draft-ietf-idr-flowspec-
              l2vpn-20.txt>.

   [RFC2119]  Bradner, S. and RFC Publisher, "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>.

   [RFC5440]  Vasseur, JP., Ed., Le Roux, JL., Ed., and RFC Publisher,
              "Path Computation Element (PCE) Communication Protocol
              (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC8174]  Leiba, B. and RFC Publisher, "Ambiguity of Uppercase vs
              Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174,
              DOI 10.17487/RFC8174, May 2017,
              <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., Varga, R., and RFC
              Publisher, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

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   [RFC8253]  Lopez, D., Gonzalez de Dios, O., Wu, Q., Dhody, D., and
              RFC Publisher, "PCEPS: Usage of TLS to Provide a Secure
              Transport for the Path Computation Element Communication
              Protocol (PCEP)", RFC 8253, DOI 10.17487/RFC8253, October
              2017, <https://www.rfc-editor.org/info/rfc8253>.

   [RFC8281]  Crabbe, E., Minei, I., Sivabalan, S., Varga, R., and RFC
              Publisher, "Path Computation Element Communication
              Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in
              a Stateful PCE Model", RFC 8281, DOI 10.17487/RFC8281,
              December 2017, <https://www.rfc-editor.org/info/rfc8281>.

   [RFC8955]  Loibl, C., Hares, S., Raszuk, R., McPherson, D., Bacher,
              M., and RFC Publisher, "Dissemination of Flow
              Specification Rules", RFC 8955, DOI 10.17487/RFC8955,
              December 2020, <https://www.rfc-editor.org/info/rfc8955>.

   [RFC9168]  Dhody, D., Farrel, A., Li, Z., and RFC Publisher, "Path
              Computation Element Communication Protocol (PCEP)
              Extension for Flow Specification", RFC 9168,
              DOI 10.17487/RFC9168, January 2022,
              <https://www.rfc-editor.org/info/rfc9168>.

9.2.  Informative References

   [I-D.ietf-idr-flowspec-v2]
              Hares, S., Eastlake, D. E., Yadlapalli, C., and S.
              Maduschke, "BGP Flow Specification Version 2", Work in
              Progress, Internet-Draft, draft-ietf-idr-flowspec-v2-01,
              21 October 2022, <https://www.ietf.org/archive/id/draft-
              ietf-idr-flowspec-v2-01.txt>.

   [I-D.ietf-pce-pcep-yang]
              Dhody, D., Beeram, V. P., Hardwick, J., and J. Tantsura,
              "A YANG Data Model for Path Computation Element
              Communications Protocol (PCEP)", Work in Progress,
              Internet-Draft, draft-ietf-pce-pcep-yang-20, 23 October
              2022, <https://www.ietf.org/archive/id/draft-ietf-pce-
              pcep-yang-20.txt>.

   [RFC4655]  Farrel, A., Vasseur, J.-P., Ash, J., and RFC Publisher, "A
              Path Computation Element (PCE)-Based Architecture",
              RFC 4655, DOI 10.17487/RFC4655, August 2006,
              <https://www.rfc-editor.org/info/rfc4655>.

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   [RFC6952]  Jethanandani, M., Patel, K., Zheng, L., and RFC Publisher,
              "Analysis of BGP, LDP, PCEP, and MSDP Issues According to
              the Keying and Authentication for Routing Protocols (KARP)
              Design Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
              <https://www.rfc-editor.org/info/rfc6952>.

   [RFC7399]  Farrel, A., King, D., and RFC Publisher, "Unanswered
              Questions in the Path Computation Element Architecture",
              RFC 7399, DOI 10.17487/RFC7399, October 2014,
              <https://www.rfc-editor.org/info/rfc7399>.

   [RFC7942]  Sheffer, Y., Farrel, A., and RFC Publisher, "Improving
              Awareness of Running Code: The Implementation Status
              Section", BCP 205, RFC 7942, DOI 10.17487/RFC7942, July
              2016, <https://www.rfc-editor.org/info/rfc7942>.

   [RFC8126]  Cotton, M., Leiba, B., Narten, T., and RFC Publisher,
              "Guidelines for Writing an IANA Considerations Section in
              RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC8283]  Farrel, A., Ed., Zhao, Q., Ed., Li, Z., Zhou, C., and RFC
              Publisher, "An Architecture for Use of PCE and the PCE
              Communication Protocol (PCEP) in a Network with Central
              Control", RFC 8283, DOI 10.17487/RFC8283, December 2017,
              <https://www.rfc-editor.org/info/rfc8283>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              Hardwick, J., and RFC Publisher, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Segment
              Routing", RFC 8664, DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

Appendix A.  Contributors

   Shankara
   Huawei Technologies
   Divyashree Techno Park,
   Whitefield Bangalore,
   Karnataka
   560066
   India

   Email: shankara@huawei.com

   Qiandeng Liang
   Huawei Technologies

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   101 Software Avenue,
   Yuhuatai District
   Nanjing
   210012
   China

   Email: liangqiandeng@huawei.com

   Cyril Margaria
   Juniper Networks
   200 Somerset Corporate Boulevard, Suite 4001
   Bridgewater, NJ
   08807
   USA

   Email: cmargaria@juniper.net

   Colby Barth
   Juniper Networks
   200 Somerset Corporate Boulevard, Suite 4001
   Bridgewater, NJ
   08807
   USA

   Email: cbarth@juniper.net

   Xia Chen
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China

   Email: jescia.chenxia@huawei.com

   Shunwan Zhuang
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China

   Email: zhuangshunwan@huawei.com

   Cheng Li
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095

Dhody, et al.              Expires 7 July 2023                 [Page 13]
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   China

   Email: c.l@huawei.com

Authors' Addresses

   Dhruv Dhody
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka 560066
   India
   Email: dhruv.ietf@gmail.com

   Adrian Farrel
   Old Dog Consulting
   Email: adrian@olddog.co.uk

   Zhenbin Li
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing
   100095
   China
   Email: lizhenbin@huawei.com

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