wdiff draft-ietf-idr-flowspec-path-redirect-01.txt draft-ietf-idr-flowspec-path-redirect-02.txt

IDR Working Group G. Van de Velde, Ed.
Internet-Draft Nokia
Intended status: Standards Track K. Patel
Expires: September March 3, 2017 2018 Arrcus
Z. Li
Huawei Technologies
March 2,
August 30, 2017

Flowspec Indirection-id Redirect
draft-ietf-idr-flowspec-path-redirect-01
draft-ietf-idr-flowspec-path-redirect-02

Abstract

Flowspec is an extension to BGP that allows for the dissemination of
traffic flow specification rules. This has many possible
applications but the primary one for many network operators is the
distribution of traffic filtering actions for DDoS mitigation. The
flow-spec standard RFC5575 [2] defines a redirect-to-VRF action for
policy-based forwarding but this mechanism is not always sufficient,
particularly if the redirected traffic needs to be steered into an
engineered path or into a service plane.

This document defines a new extended community known as redirect-to-
indirection-id (32-bit) flowspec action to provide
redirect-to-indirection-id. This extended community triggers
advanced redirection capabilities on to flowspec clients. When
activated, the this flowspec extended community is used by a flowspec
client to find the correct next-hop entry information within a localised
indirection-id mapping table.

The functionality present detailed in this draft document allows a network
controller to decouple the BGP flowspec functionality redirection instruction from
the creation and maintainance
of the network's service plane itself including the setup of tunnels
and other service constructs that could be managed by other network
devices. actual redirection path selected.

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 [1].

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
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This Internet-Draft will expire on September March 3, 2017. 2018.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2
2. indirection-id and indirection-id table . . . . . . . . . . . 3
3. Use Case Scenarios . . . . . . . . . . . . . . . . . . . . . 4
3.1. Redirection shortest Path tunnel . . . . . . . . . . . . 4
3.2. Redirection to path-engineered tunnels . . . . . . . . . 5
3.3. Redirection to complex dynamically constructed tunnels . 6
4. Redirect to indirection-id Community . . . . . . . . . . . . 7
5. Redirect using localised indirection-id mapping table . . . . 8
6. Validation Procedures . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. Contributor Addresses . . . . . . . . . . . . . . . . . . . . 9
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
11.1. Normative References . . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Additional indirection_id types waiting for use-case
description . . . . . . . . . . . . . . . . . . . . 12 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 12

1. Introduction

Flowspec RFC5575 [2] is an extension to BGP that allows for the dissemination of
traffic flow specification rules. This has many possible applications, however
applications but the primary one for many network operators is the
distribution of traffic filtering actions for DDoS mitigation. The
flow-spec standard RFC5575 [2] defines a redirect-to-VRF action for
policy-based forwarding but this mechanism is not always sufficient,
particularly if the redirected traffic needs to be steered onto an
explicite path.

Every flowspec policy route is effectively a rule, consisting of a
matching part (encoded in the NLRI field) and an action part (encoded
in one or more BGP extended communities). The flow-spec standard
RFC5575 [2] defines widely-used filter actions such as discard and
rate limit; it also defines a redirect-to-VRF action for policy-based
forwarding. Using the redirect-to-VRF action to steer traffic
towards an alternate destination is useful for DDoS mitigation but
using this technology can be cumbersome when there is need to steer
the traffic onto an engineered explicitely defined traffic path.

This draft proposes a new redirect-to-indirection-id flowspec action
facilitating an
making use of a 32-bit indirection-id within a new extended
community. Each indirection-id serves as anchor point point, for policy-based policy-
based forwarding onto an
engineered explicite path or into on a service plane. The flowspec client
consuming and utilizing the new client.

A flowspec indirection-id extended-
community constructs the redirection information based upon
information found within indirection service plane can be create when a localised
single 32-bit flowspec indirection-id mapping table.
The localised mapping table is a table construct, sequenced by maps towards a pool of
explicite paths.

2. indirection-id and indirection-id table key, providing next-hop information.

The redirect-to-indirection-id flowspec action indirection-id is encoded in a newly
defined BGP extended community. The type of redirection is
identified 32-bit unsigned number, used as an extended community indirection-id type field.

This draft defines the indirection-id extended-community and anchor point
on a few
wellknown indirection-id types. flowspec client. The specific mechanics to construct
a localised indirection-id mapping table are out-of-scope of this
document.

2. indirection-id and indirection-id table

An indirection-id is an abstract number (32-bit value) used as
identifier for on a flowspec client the
lookup key-value within a localised list of potential indirection decision.
paths. The indirection-id will allow a the flowspec client to redirect steer
traffic into to a service plane particular path or consequently onto into an engineered traffic path. For example, when a
BGP flowspec controller signals indirection service plane by
doing a flowspec client recursive key-value lookup.

The indirection-id table is the table containing an ordered list of
indirection-id
extended community, then key-values, ordered by indirection-id type; where each
key-value maps towards a particular path or set of paths. The
indirection-id type MAY provide additional context about the
indirection-id 32-bit value. The flowspec client uses MUST use the
indirection-id
to make a recursive lookup to find as key-value within the next-hop information. The indirection-id is used type
corresponding indirection-id table to find locate the explicite path and
corresponding next-hop information
within the localised indirection mapping table. information.

The configuration of the indirection-id table on a flowspec client
MAY happen out-of-band from BGP flowspec and is a localised construct
on the each router. The For some use-case scenarios the indirection-id table is constructed out of table keys, each mapped type
provides additional (maybe even fully sufficient) context towards a
flowspec client to
localised redirection information. Each table key deduct automatic, without explicite out-of-band
configuration, the indirection-id table. For example, when the
indirection-id refers to a segment routing node-id [6], then
indirection-id type can provide the flowspec client the awareness
that the indirection-id is composed by a segment routing node-id. For this
example the
combining indirection-id type and an allows the flowspec clients to do a
recursive lookup using traditional segment routing technology.

To summarise, each indirection-id 32-bit value.
Each key-value entry in the indirection-table key indirection-
table maps recursively to sufficient next-hop information (parameters
regarding encapsulation, egress-interface, QoS, etc...) to
successfully redirect indirect traffic according flowspec controller
expectations.

3. Use Case Scenarios

This section describes use-case scenarios when deploying redirect-to-
indirection-id.

3.1. Redirection shortest Path tunnel

Example: Indirection-ID community types to be used:

o 0 (localised ID): When the intent is to use a localised
Indirection-id table on the flowspec client

o 1 (Node ID): When the intent is to use a Segment Routing based
Indirection-id table on the flowspec client

Description:

The first use-case describes an example where a single flowspec route
(i.e. flowspec_route#1)
is sent by from a BGP flowspec controller to many BGP flowspec clients.
This single BGP flowspec route will instruct carries the redirect-to-indirection-id to all
Flowspec
flowspec clients to redirect matching dataflows onto a shortest-path
tunnel pointing towards a single IP destination address. remote destination.

For this first use-case scenario, each flowspec client receives a
flowspec route (flowspec_route#1) which has routes. The flowspec routes have the extended redirect-to-
indirection-id extended community attached. The extended redirect-
to-indirection-id community contains the table key consisting out of
the community attached. Each redirect-to-indirection-id
community embeds two relevant components: (1) 32-bit indirection-id type
key-value and (2) indirection-id 32-bit value. type. The table
key indirection-id type is
used on the flowspec client to map to identify the corresponding next-
hop information indirection-id table, and the
actual 32-bit indirection-id key-value is used within the local
indirection-id table. table to locate the corresponding next-hop
information. The finite result of this operation is a remote tunnel end-point IP address
together with accordingly sufficient
tunnel encapsulation information to forward and encapsulate the data-packet accordingly. data-
packet accordingly to a remote tunnel end-point.

Requirements:

For redirect to shortest path tunnel it is required that the tunnel
MUST be operational up-and-running and allow packets to be unidirectional
exchanged between tunnel head- and tail-end.

3.2. Redirection to path-engineered tunnels

Example: Indirection-ID community types to be used:

o 0 (localised ID): When the intent is to use a localised
Indirection-id table on the flowspec client client. This requires out-
of-band configuration of the indirection-id table

o 6 (Binding Segment 1 (Node ID): When the intent is to use a Segment Routing based
Indirection-id table on the flowspec client client. This requires that
Segment Routing is enabled on the flowspec client.

3.2. Redirection to path-engineered tunnels

Description:

The second use-case describes an example where a flowspec controler
injects a single flowspec
route which gets distributed is sent from a BGP flowspec controller to many BGP flowspec
clients. This single BGP flowspec route intends carries the redirect-to-
indirection-id extended community to instruct all
Flowspec flowspec clients with
instructions to redirect corresponding matching dataflows onto a path engineered
tunnel. It is expected that each of the path engineered tunnels is
instantiated by out-of-band mechanisms. Each used path
engineered tunnel has a unque table key identifier. consequently, the
table key configuration and can be uniquely identifies exactly -one- path engineered tunnel.

In this use-case example,
identified by the flowspec controller sends a flowspec
route to each combination of the flowspec clients (1) indirection-id 32-bit key-value
and (2) indirection-id type.

For this second use-case scenario, each flowspec route has a
redirect-to-indirection-id client receives
flowspec routes. The flowspec routes have the extended redirect-to-
indirection-id community attached. The Each redirect-to-indirection-id extended
community embeds table key
information and hence provides two relevant components similar as explained in
previous use-case. However the finite result of this operation is
sufficient tunnel encapsulation information to select forward and
encapsulate the
corresponding path-engineered tunnel data-packet accordingly to redirect the packet according
the flowspec controller expectations.

Segment Routing Example:

A concrete embodiment of a Segment Routing use-case example is found
in networks where remote tunnel end-point
using a path engineered tunnels are created by a tunnel construction.

Segment Routing MPLS label stack. In such a deployment, Example:

For this example the indirection-id
provides an anchorpoint reference to type informs the flowspec client
that the indirection-id 32-bit key-value references a Segment Routing
Binding SID.
However, the indirection-id type provides a pointer to the Binding
SID semantics to be used. The Binding SID is a segment identifier value (as per
segment routing definitions in [I-D.draft-ietf-spring-
segment-routing] [I-D.draft-ietf-spring-segment-
routing] [6]) used to associate an explicit path. The Binding SID
and corresponding path engineered tunnel can for example be setup by
a controller using BGP as specified in [I-D.sreekantiah-
idr-segment-routing-te] [I-D.sreekantiah-idr-segment-
routing-te] [5] or by using PCEP as detailed in draft-
ietf-pce-segment-routing draft-ietf-pce-
segment-routing [7]. To conclude, when a BGP speaker at some point
in time receives a flow-spec route with an extended
'redirect-to-indirection-id' 'redirect-to-
indirection-id' community, it installs a traffic filtering rule that
matches particular packets and redirects them onto an explicit path
associated with the corresponding Binding SID. The encoding of the
Binding SID within the redirect-to-indirection-id extended community
is specified in section 4.

Requirements:

For redirect to path engineered tunnels it is required that the
engineered tunnel MUST be active and allow packets to be
unidirectional exchanged between tunnel head- and tail-end.

3.3. Redirection to complex dynamically constructed tunnels

Example: Indirection-ID community types to be used:

o 0 (localised ID) with TID: ID): When the intent is to use a localised
Indirection-id table, then TID (Table-ID) field could be used to
sequence multiple redirect-to-indirection-id actions together table on the flowspec client. This requires out-
of-band configuration of the indirection-id table.

o 6 (Binding Segment ID): When the intent is to
construct use a more complex path engineered tunnel. The order of
sequencing Segment
Routing based Indirection-id table on the redirection information may be identified by using flowspec client. This
requires out-of-band configuration of the TID field. Binding Segment IDs.

3.3. Redirection to complex dynamically constructed tunnels

Description:

A third use-case describes the application and redirection towards
complex dynamically constructed tunnels. For this use-case a BGP
flowspec controller injects a flowspec route with multiple 'redirect-
to-indirection-id' two 'redirect-to-
indirection-id' communities attached. attached, each tagged with a different
Table-ID (TID). A recipient flowspec client may use the Table-ID (TID) field embedded within each 'redirect-to-
indirection-id' community to
sequence the flowspec redirect information. The
complex dynamically constructed tunnel is A common use-case
scenario would for example be the product dynamic construction of
concatenating the available redirect information (i.e. MPLS Segment
Routing Labels). Central Egress Path Engineered tunnel [4] or next-next-hop
tunnels.

Segment Routing Example:

i.e. a classic Segment Routing example using complex tunnels is found
in DDoS mitigation and traffic offload. Suspicious traffic (e.g.
dirty traffic flows) may be steered into a Segment Routing Central
Egress Path Engineered tunnel [4]. For this particular complex dynamic redirect
tunnel embodiment, construction, a first redirect-to-indirection-
id redirect-to-indirection-id (i.e. TID=0)
is used to redirect traffic into a tunnel towards a particlar egress
router, while a second redirect-to-indirection-id (i.e. TID=1) is
used to steer traffic beyond the particular egress router towards a
pre-identified interface/peer.

For this DDoS use-case, in its simplest embodiment, the flowspec
client must dynamically append 2 MPLS Segment Routing labels. A
first MPLS Segment Routing label (the outer label) to steer the original
packet to the egress node (and hence using use a shortest path tunnel),
while a second MPLS label (matching redirect-to-indirection-id with
TID=1), the inner label, to steer on the egress router the original
packet to a pre-defined interface/peer. The basic data-plane
principles are documented by [4].

Requirements:

To achieve redirection towards complex dynamically constructed
tunnels, for each flowspec route, multiple indirection-ids, each
using a unique Tunnel ID may imposed are pushed upon a given flowspec policy
rule. It is required that there is synchronisation established
between the data- data-plane and control-plane of all relevant devices
involved. Each complex dynamically constructed tunnel MUST be
operational and allow packets to be unidirectional exchanged between
tunnel head- and tail-end before it should can be used to redirect traffic.

Example: Indirection-ID community types to be used:

o 0 (localised ID) with TID: When the intent is to use a localised
Indirection-id table, then the TID (Table-ID) MUST be used to
sequence multiple redirect-to-indirection-id actions to construct
a more complex path engineered tunnel. The order of sequencing
the redirection information MUST be identified by using the TID
field.

4. Redirect to indirection-id Community

This document defines a new BGP extended community known as a
Redirect-to-indirection-id extended community. This extended
community is a new transitive extended community with the Type and
the Sub-Type field to be assigned by IANA. The format of this
extended community is show in Figure 1.

Figure 1

The meaning of the extended community fields are as follows:

Type: 1 octet to be assigned by IANA.

Sub-Type: 1 octet to be assigned by IANA.

Flags: 1 octet field. Following Flags are defined.

0 1
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| RES | TID |C|
+-+-+-+-+-+-+-+-+

Figure 2

The least-significant Flag bit is defined as the 'C' (or copy) bit.
When the 'C' bit is set the redirection applies to copies of the
matching packets and not to the original traffic stream.

The 'TID' field identifies a 4 bit Table-id field. This field is
used to provide the flowspec client an indication how and where to
sequence the received indirection-ids to redirecting traffic. TID
value 0 indicates that Table-id field is NOT set and SHOULD be
ignored. On a flowspec client the indirection-id with lowest TID
MUST be processed first for a flowspec route.

All bits other than the 'C' and 'TID' bits MUST be set to 0 by the
originating BGP speaker and ignored by receiving BGP speakers.

Indirection ID: 1 octet value. This draft defines following
indirection_id Types:

0 - Localised ID (The flowspec client uses the received
indirection-id to lookup the redirection information in the
localised indirection-id table.)

1 - Node ID (The flowspec client uses the received indirection-id
as a Segment Routing Node ID to redirect traffic towards)

6 - Binding Segment ID (The flowspec client uses the received
indirection-id as a Segment Routing Binding Segment ID to redirect
traffic towards) [I-D.draft-ietf-spring-segment-routing] [6]

5. Redirect using localised indirection-id mapping table

When a BGP flowspec client receives a flowspec policy route with a
'redirect to indirection-id'
redirect-to-indirection-id extended community attached and the route
represents the best BGP path, it will install a flowspec traffic
filtering rule matching the IP tupples described by the flowpsec NLRI
field and consequently redirects the flow (C=0) or copies the flow
(C=1) using the information identified by the
'redirect-to-indirection-id' 'redirect-to-
indirection-id' community.

6. Validation Procedures

The validation check described in RFC5575 [2] and revised in [3]
SHOULD be applied by default to received flow-spec routes with a
'redirect to indirection-id' extended community. This means that a
flow-spec route with a destination prefix subcomponent SHOULD NOT be
accepted from an EBGP peer unless that peer also advertised the best
path for the matching unicast route.

While it MUST NOT happen, and is seen as invallid combination, it is
possible from a semenatics perspective to have multiple clashing
redirect actions defined within a single flowspec rule. For best and
consistant RFC5575 flowspec redirect behavior the redirect as
documented by RFC5575 MUST not be broken, and hence when a clash
occurs, then RFC5575 based redirect SHOULD take priority.
Additionally, if the 'redirect to indirection-id' does not result in
a valid redirection, then the flowspec rule must be processed as if
the 'redirect to indirection-id' community was not attached to the
flowspec route and MUST provide an indication within the BGP routing
table that the respective 'redirect to indirection-id' resulted in an
invalid redirection action.

7. Security Considerations

A system using 'redirect-to-indirection-id' extended community can
cause during the redirect mitigation of a DDoS attack result in
overflow of traffic received by the mitigation infrastructure.

8. Acknowledgements

This document received valuable comments and input from IDR working
group including Adam Simpson, Mustapha Aissaoui, Jan Mertens, Robert
Raszuk, Jeff Haas, Susan Hares and Lucy Yong.

9. Contributor Addresses

Below is a list of other contributing authors in alphabetical order:

Arjun Sreekantiah
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA

Email: asreekan@cisco.com

Nan Wu
Huawei Technologies
Huawei Bld., No. 156 Beiquing Rd
Beijing 100095
China

Email: eric.wu@huawei.com

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

Email: zhuangshunwan@huawei.com

Wim Henderickx
Nokia
Antwerp
BE

Email: wim.henderickx@nokia.com

Figure 3

10. IANA Considerations

This document requests a new type and sub-type for the Redirect to
indirection-id Extended community from the "Transitive Extended
community" registry. The Type name shall be "Redirect to
indirection-id Extended Community" and the Sub-type name shall be
'Flow-spec Redirect to 32-bit Path-id'.

In addition, this document requests IANA to create a new registry for
Redirect to indirection-id Extended Community INDIRECTION-IDs as
follows:

Under "Transitive Extended Community:"

Registry: "Redirect Extended Community indirection_id"

Reference: [RFC-To-Be]

Registration Procedure(s): First Come, First Served

Registry: "Redirect Extended Community indirection_id"

Value Code Reference

0 Localised ID [RFC-To-Be]
1 Node ID [RFC-To-Be]
2 Agency ID [RFC-To-Be]
3 AS (Autonomous System) ID [RFC-To-Be]
4 Anycast ID [RFC-To-Be]
5 Multicast ID [RFC-To-Be]
6 Tunnel ID (Tunnel Binding ID ) [RFC-To-Be]
7 VPN ID [RFC-To-Be]
8 OAM ID [RFC-To-Be]
9 ECMP (Equal Cost Multi-Path) ID [RFC-To-Be]
10 QoS

Value Code Reference

0 Localised ID [RFC-To-Be]
11 Bandwidth-Guarantee
1 Node ID [RFC-To-Be]
12 Security
6 Tunnel ID [RFC-To-Be]
13 Multi-Topology (Tunnel Binding ID ) [RFC-To-Be]

Figure 4

11. References

11.1. Normative References

[1] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997,
<http://xml.resource.org/public/rfc/html/rfc2119.html>.

[2] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>.
<https://www.rfc-editor.org/info/rfc5575>.

11.2. Informative References

[3] Uttaro, J., Filsfils, C., Alcaide, J., and P. Mohapatra,
"Revised Validation Procedure for BGP Flow
Specifications", January 2014.

[4] Filsfils, C., Previdi, S., Aries, E., Ginsburg, D., and D.
Afanasiev, "Segment Routing Centralized Egress Peer
Engineering", October 2015.

[5] Sreekantiah, A., Filsfils, C., Previdi, S., Sivabalan, S.,
Mattes, P., and S. Lin, "Segment Routing Traffic
Engineering Policy using BGP", October 2015.

[6] Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
Shakir, R., Bashandy, A., Horneffer, M., Henderickx, W.,
Tantsura, J., Crabbe, E., Milojevic, I., and S. Ytti,
"Segment Routing Architecture", December 2015.

[7] Sivabalan, S., Medved, M., Filsfils, C., Litkowski, S.,
Raszuk, R., Bashandy, A., Lopez, V., Tantsura, J.,
Henderickx, W., Hardwick, J., Milojevic, I., and S. Ytti,
"PCEP Extensions for Segment Routing", December 2015.

Appendix A. Additional indirection_id types waiting for use-case
description

This section is a placeholder and collection of potential additional
indirection_id types. The current use-cases do not require these
particular indirection types, however at later stage when use-cases
are identified they may be added to the body of teh draft.

2 - Agency ID (The flowspec client uses the received indirection-id
as a Segment Routing Agency ID to redirect traffic towards)

3 - AS (Autonomous System) ID (The flowspec client uses the received
indirection-id as a Segment Routing Autonomous System ID to redirect
traffic towards)

4 - Anycast ID (The flowspec client uses the received indirection-id
as a Segment Routing Anycast ID to redirect traffic towards)

5 - Multicast ID (The flowspec client uses the received indirection-
id as a Segment Routing Multicast ID to redirect traffic towards)

7 - VPN ID (The flowspec client uses the received indirection-id as a
Segment Routing VPN ID to redirect traffic towards)
8 - OAM ID (The flowspec client uses the received indirection-id as a
Segment Routing OAM ID to redirect traffic towards)

9 - ECMP (Equal Cost Multi-Path) ID (The flowspec client uses the
received indirection-id as a Segment Routing PeerSet ID to redirect
traffic towards)

10 - QoS ID (The flowspec client uses the received indirection-id as
a Segment Routing QoS ID to redirect traffic towards)

11 - Bandwidth-Guarantee ID (The flowspec client uses the received
indirection-id as a Segment Routing Bandwidth-Guarantee ID to
redirect traffic towards)

12 - Security ID (The flowspec client uses the received indirection-
id as a Segment Routing Security ID to redirect traffic towards)

13 - Multi-Topology ID (The flowspec client uses the received
indirection-id as a Segment Routing Multi-Topology ID to redirect
traffic towards)

Authors' Addresses

Gunter Van de Velde (editor)
Nokia
Antwerp
BE

Email: gunter.van_de_velde@nokia.com

Keyur Patel
Arrcus
USA

Email: keyur@arrcus.com

Zhenbin Li
Huawei Technologies
Huawei Bld., No. 156 Beiquing Rd
Beijing 100095
China

Email: lizhenbin@huawei.com