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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (March 13, 2017) is 2599 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 i2rs M. Wang, Ed. 3 Internet-Draft J. Chen 4 Intended status: Informational Huawei 5 Expires: September 14, 2017 R. Gu 6 China Mobile 7 March 13, 2017 9 Information Model of Control-Plane and User-Plane separation BNG 10 draft-wcg-i2rs-cu-separation-infor-model-00 12 Abstract 14 To improve network resource utilization and reduce the operation 15 expense, the Control-Plane and User-Plane separation conception is 16 raised [draft-gu-nfvrg-cloud-bng-architecture-00]. This document 17 describes the information model for the interface between Control- 18 Plane and User-Plane separation BNG. This information model may 19 involve both control channel interface and configuration channel 20 interface. The interface for control channel allows the Control- 21 Plane to send the user's information table to the User-Plane, and the 22 User-Plane to report the statistics information to the Control-Plane, 23 etc. The interface for configuration channel is in charge of the 24 version negotiation between the CP and UP, the configuration for the 25 devices of CP and UP, and the report of UP's capabilities, etc. The 26 information model defined in this document enable defining a 27 standardized data model. Such a data model can be used to define an 28 interface to the CU separation BNG. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at http://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on September 14, 2017. 47 Copyright Notice 49 Copyright (c) 2017 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (http://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Concept and Terminology . . . . . . . . . . . . . . . . . . . 4 66 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 67 3. Generic Control Plane and User Plane separation BNG Overview 4 68 4. Information Model . . . . . . . . . . . . . . . . . . . . . . 4 69 4.1. Information Model for Control-Plane . . . . . . . . . . . 5 70 4.1.1. User-Related Information . . . . . . . . . . . . . . 6 71 4.1.1.1. User Information Model . . . . . . . . . . . . . 6 72 4.1.1.2. IPv4 Information Model . . . . . . . . . . . . . 7 73 4.1.1.3. IPv6 Information Model . . . . . . . . . . . . . 7 74 4.1.1.4. QoS Information Model . . . . . . . . . . . . . . 8 75 4.1.2. Port Related Information . . . . . . . . . . . . . . 9 76 4.1.2.1. Port Information Model . . . . . . . . . . . . . 9 77 4.1.3. Device Related Information . . . . . . . . . . . . . 10 78 4.1.3.1. Address field distribute Table . . . . . . . . . 10 79 4.2. Information Model for User Plane . . . . . . . . . . . . 11 80 4.2.1. User Related Information . . . . . . . . . . . . . . 11 81 4.2.1.1. User Information Model . . . . . . . . . . . . . 11 82 4.2.1.2. IPv4 Information Model . . . . . . . . . . . . . 12 83 4.2.1.3. IPv6 Information Model . . . . . . . . . . . . . 13 84 4.2.1.4. QoS Information Model . . . . . . . . . . . . . . 14 85 4.2.1.5. Traffic Statistics Infor . . . . . . . . . . . . 15 86 4.2.2. Port Related Information . . . . . . . . . . . . . . 16 87 4.2.2.1. Port Information Model . . . . . . . . . . . . . 16 88 4.2.2.2. Port Resources of UP . . . . . . . . . . . . . . 17 89 4.2.3. Device Related Information . . . . . . . . . . . . . 18 90 4.2.3.1. Address field distribute Table . . . . . . . . . 18 91 5. Security Considerations . . . . . . . . . . . . . . . . . . . 19 92 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 93 7. Normative References . . . . . . . . . . . . . . . . . . . . 19 94 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 96 1. Introduction 98 The rapid development of new services, such as 4K, IoT, etc, and 99 increasing number of home broadband service users present some new 100 challenges for BNGs such as: 102 Low resource utilization: The traditional BNG acts as both a 103 gateway for user access authentication and accounting and an IP 104 network's Layer 3 edge. The mutually affecting nature of the 105 tightly coupled control and forwarding planes makes it difficult 106 to achieve the maximum performance of either plane. 108 Complex management and maintenance: Due to the large number of 109 traditional BNGs, a network must have each device configured one 110 at a time when deploying global service policies. As the network 111 expands and new services are introduced, this deployment mode will 112 cease to be feasible as it is unable to manage services 113 effectively and rectify faults rapidly. 115 Slow service provisioning: The coupling of control planes and data 116 planes, in addition to a distributed network control mechanism, 117 means that any new technology has to rely heavily on the existing 118 network devices. 120 To address these challenges, cloud-based BNG with C/U separated 121 conception is raised [draft-gu-nfvrg-cloud-bng-architecture-00]. The 122 main idea of Control-Plane and User-Plane separation method is to 123 extract and centralize the user management functions of multiple BNG 124 devices, forming an unified and centralized control plane (CP). And 125 the traditional router's Control Plane and forwarding plane are both 126 preserved on BNG devices in the form of a user plane (UP). 128 This document describes the information model for the interface 129 between Control-Plane and User-Plane separation BNG. This 130 information model may involve both control channel interface and 131 configuration channel interface. The interface for control channel 132 allows the Control-Plane to send the user's information table to the 133 User-Plane, and the User-Plane to report the statistics information 134 to the Control-Plane, etc. The interface for configuration channel 135 is in charge of the version negotiation between the CP and UP, the 136 configuration for the devices of CP and UP, and the report of UP's 137 capabilities, etc. The information model defined in this document 138 enable defining a standardized data model. Such a data model can be 139 used to define an interface to the CU separation BNG. 141 2. Concept and Terminology 143 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 144 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 145 document are to be interpreted as described in [RFC2119]. 147 2.1. Terminology 149 BNG: Broadband Network Gateway. A broadband remote access server 150 (BRAS, B-RAS or BBRAS) routes traffic to and from broadband remote 151 access devices such as digital subscriber line access multiplexers 152 (DSLAM) on an Internet service provider's (ISP) network. BRAS can 153 also be referred to as a Broadband Network Gateway (BNG). 155 CP: Control Plane. The CP is a user control management component 156 which support to manage UP's resources such as the user entry and 157 forwarding policy 159 UP: User Plane. UP is a network edge and user policy implementation 160 component. 162 3. Generic Control Plane and User Plane separation BNG Overview 164 Briefly, a C/U separated BNG is made up of a CP and a UP. The CP is 165 a user control management component which support to manage UP's 166 resources such as the user entry and forwarding policy, for example, 167 the access bandwidth and priority management. And the UP is a 168 network edge and user policy implementation component. It can 169 support the forwarding plane functions on traditional BNG devices, 170 such as traffic forwarding, QoS, and traffic statistics collection, 171 and it can also support the control plane functions on traditional 172 BNG devices, such as routing, multicast, etc. 174 In CP's view, the UP provides the control management network 175 resources such as user's formation, access bandwidth, etc. The CP 176 manages these resources and according to specific service's 177 requirements to generate several tables which contains a set of 178 rules. And then CP sends these tables to UP. 180 In UP's view, the CP generates tables and provides the rules. The UP 181 receives these tables, parses it, matches these rules, and then 182 performs corresponding actions. 184 4. Information Model 186 This section describes information model that represents the concept 187 of the interface of CU separation BNG which is language and protocol 188 neutral. 190 The following figure describes the Overview of Information Model for 191 CU separation BNG. 193 +---CP: (generate Tables, which including several rules) 194 | | 195 | +---PORT information: rule 1, 2, 3 ... 196 | | 197 | +---User Infor: rule 1, 2, 3 ... 198 | | 199 | +---IPv4 Infor: rule 1, 2, 3 ... 200 | | 201 | +---IPv6 Infor: rule 1, 2, 3 ... 202 | | 203 | +---QoS: rule 1, 2, 3 ... 204 | | 205 | +---Address field distribute: rule 1, 2, 3 ... 206 | 207 +---UP 208 | 209 +---Case 1:(report resources and statistical information) 210 | | 211 | +---PORT RESOURCES of UP 212 | | 213 | +---Traffic statistics 214 | 215 +---Case 2:(match rules then perform corresponding actions) 216 | 217 +---PORT information: match rules than action 218 | 219 +---User Infor: match rules than action 220 | 221 +---IPv4 Infor: match rules than action 222 | 223 +---IPv6 Infor: match rules than action 224 | 225 +---QoS: match rules than action 226 | 227 +---Address field distribute: match rules than action 229 4.1. Information Model for Control-Plane 231 This section describes information model for the interface of 232 Control-Plane (CP). As mentioned in section 3, the CP is a user 233 control management component which support to manage UP's resources 234 and forwarding policy, and base on these resources and specific 235 requirements of user's service, generate several tables which 236 contains a set of matching rules. 238 4.1.1. User-Related Information 240 4.1.1.1. User Information Model 242 The User information may contains a set of User's information. Base 243 on above information CP generates corresponding table and matching 244 rules. And then sends it to UP. 246 The Figure below illustrates the User Information Table of Control- 247 Plane: 249 +---CP: (generate Tables, which contains several rules) 250 | 251 +---User-Infor 252 | 253 +---SubId 254 | 255 +---SubMac 256 | 257 +---AccessType 258 | 259 +---SessionID 260 | 261 +---InnerVlanId 262 | 263 +---OuterVlanId 264 | 265 +---SubIf 267 User Information may include: 269 SubID: Identifier of user. 271 SubMac: MAC address of user. 273 AccessType: Indicate the access type, for example PPPoE, IPoE, 274 etc. 276 SessionID: The Session Identifier, for example PPPoE session ID. 278 InnerVlanID: Identifier of inner VLAN. 280 OuterVlanID: Identifier of outer VLAN. 282 SubIF: Index of user's interface. 284 4.1.1.2. IPv4 Information Model 286 The User-IPv4 information may contains a set of User's information 287 and corresponding IPv4 address information. Base on above 288 information CP generates corresponding table and matching rules. And 289 then sends it to UP. 291 The Figure below illustrates the IPv4 Information Table of Control- 292 Plane: 294 +---CP: (generate Tables, which contains several rules) 295 | 296 +---IPv4-Infor 297 | 298 +---UserID 299 | 300 +---SubIPv4 301 | 302 +---MaskLen 303 | 304 +---GateWay 305 | 306 +---VRF 308 IPv4-Infor includes: 310 UserID: Identifier of User. 312 SubIPv4: IPv4 address of user. 314 MaskLen: Mask Length. 316 GateWay: Gate Way information of user. 318 VRF: Identifier of VRF. 320 4.1.1.3. IPv6 Information Model 322 The User-IPv6 information may contains a set of User's information 323 and corresponding IPv6 address information. Base on above 324 information CP generates corresponding table and matching rules. And 325 then sends it to UP. 327 The Figure below illustrates the IPv6 Information Table of Control- 328 Plane: 330 +---CP: (generate Tables, which contains several rules) 331 | 332 +---IPv6-Infor 333 | 334 +---UserID 335 | 336 +---SubIPv6 337 | 338 +---IPv6MaskLen 339 | 340 +---PDAddr 341 | 342 +---PDMasklen 343 | 344 +---Vrf 346 IPv6 Infor includes: 348 UserID: Identifier of User. 350 SubIPv6: IPv6 address of user. 352 IPv6MaskLen: Mask Length. 354 PDAddr: PD address. 356 PDMaskLen: PD Mask Length. 358 VRF: Identifier of VRF. 360 4.1.1.4. QoS Information Model 362 In CU separation BNG information model, the Control-Plane (CP) 363 generates the QoS Table base on managed UP's bandwidth resources and 364 specific QoS requirements of user's services. This table may 365 contains a set of QoS matching rules. The CP sends this table to UP, 366 UP receives and parses this table, matches these QoS rules, and then 367 performs corresponding actions. 369 The Figure below illustrates the QoS Table of Control-Plane: 371 +---CP: (generate Tables, which including several rules) 372 | 373 +---PORT-infor 374 | 375 +--- UserId 376 | 377 +--- QosSubCarCir 378 | 379 +--- QosSubCarPir 380 | 381 +--- QosSubCarCbs 382 | 383 +--- QosSubCarPbs 385 UserId: Identifier of user. 387 QosSubCarCir: Committed Information Rate. 389 QosSubCarPir: Peak information rate. 391 QosSubCarCbs:Committed Burst Size. 393 QosSubCarPbs:Peak Burst Size. 395 4.1.2. Port Related Information 397 4.1.2.1. Port Information Model 399 The Port is a logical construct that identifies a specific process or 400 a type of network service. In CU separation BNG information model, 401 the Control-Plane (CP) generate the Port-Infor table base on the 402 port-resources, which are received from the User-Plane (UP), and the 403 specific requirements of user's services. This table contains a set 404 of Port's matching rules. And then the CP sends this Port-Infor to 405 UP 407 The Figure below illustrates the Port Information Table of Control- 408 Plane: 410 +---CP: (generate tables, which contains several rules) 411 | 412 +---PORT-infor 413 | 414 +---IfIndex 415 | 416 +---BasEn 418 IfIndex: Index for interface. 420 BasEn: Enable the Bas Port. 422 4.1.3. Device Related Information 424 4.1.3.1. Address field distribute Table 426 In CU separation BNG information model, the Control-Plane (CP) 427 generates and sends this Address field distribute Information table 428 to UP. The UP receives and parses this table, matches corresponding 429 rules presented in Address-field-distribute, and then performs 430 actions 432 The Figure below illustrates the Address field distribute Table of 433 Control-Plane: 435 +---UP:(match rules then perform corresponding actions) 436 | 437 +---PORT-infor 438 | 439 +---AddressSegment 440 | 441 +---AddressSegmentMask 442 | 443 +---AddressSegmentVrf 444 | 445 +---NextHop 446 | 447 +---IfIndex 448 | 449 +---MaskLen 451 AddressSegment: The address segment information. 453 AddressSegmentMask: The address segment mask information. 455 AddressSegmentVrf: The address segment VRF. 457 NextHop: The next hop. 459 IfIndex: The index of the outing interface. 461 MaskLen: The Mask length. 463 4.2. Information Model for User Plane 465 This section describes information model for the interface of User- 466 Plane (UP). As mentioned in section 3, the CP is a network edge and 467 user policy implementation component. It supports: Forwarding plane 468 functions on traditional BNG devices, including traffic forwarding, 469 QoS, and traffic statistics collection Control plane functions on 470 traditional BNG devices, including routing, multicast, and MPLS. 472 In CU separation BNG information model, the CP generates tables and 473 provides the rules. The UP plays two roles: 475 1. It receives these tables, parses it, and matches these rules, 476 then performs corresponding actions. 478 2. It reports the resources and statistical information to CP. 480 4.2.1. User Related Information 482 4.2.1.1. User Information Model 484 The User information may contains a set of User's information. In CU 485 separation BNG information model, the CP generates and sends this 486 Information table to UP. The UP parses this table, matches 487 corresponding rules, and then performs next step of actions. 489 The Figure below illustrates the User Information Table of User- 490 Plane: 492 +---CP: (generate Tables, which contains several rules) 493 | 494 +---User-Infor 495 | 496 +---SubId 497 | 498 +---SubMac 499 | 500 +---AccessType 501 | 502 +---SessionID 503 | 504 +---InnerVlanId 505 | 506 +---OuterVlanId 507 | 508 +---SubIf 510 User Information may include: 512 SubID: Identifier of user. 514 SubMac: MAC address of user. 516 AccessType: Indicate the access type, for example PPPoE, IPoE, 517 etc. 519 SessionID: The Session Identifier, for example PPPoE session ID. 521 InnerVlanID: Identifier of inner VLAN. 523 OuterVlanID: Identifier of outer VLAN. 525 SubIF: Index of user's interface. 527 4.2.1.2. IPv4 Information Model 529 The IPv4 information may contains a set of User's information and 530 corresponding IPv4 address information. In CU separation BNG 531 information model, the CP generates and sends this Information table 532 to UP. The UP parses this table, matches corresponding rules, and 533 then performs next step of actions. 535 The Figure below illustrates the IPv4 Information Table of User- 536 Plane: 538 +---CP: (generate Tables, which contains several rules) 539 | 540 +---IPv4-Infor 541 | 542 +---UserID 543 | 544 +---SubIPv4 545 | 546 +---MaskLen 547 | 548 +---GateWay 549 | 550 +---VRF 552 IPv4-Infor includes: 554 UserID: Identifier of User. 556 SubIPv4: IPv4 address of user. 558 MaskLen: Mask Length. 560 GateWay: Gate Way information of user. 562 VRF: Identifier of VRF. 564 4.2.1.3. IPv6 Information Model 566 The IPv6 information may contains a set of User's information and 567 corresponding IPv6 address information. In CU separation BNG 568 information model, the CP generates and sends this Information table 569 to UP. The UP parses this table, matches corresponding rules, and 570 then performs next step of actions. 572 The Figure below illustrates the IPv6 Information Table of User- 573 Plane: 575 +---CP: (generate Tables, which contains several rules) 576 | 577 +---IPv6-Infor 578 | 579 +---UserID 580 | 581 +---SubIPv6 582 | 583 +---IPv6MaskLen 584 | 585 +---PDAddr 586 | 587 +---PDMasklen 588 | 589 +---Vrf 591 IPv6-Infor includes: 593 UserID: Identifier of User. 595 SubIPv6: IPv6 address of user. 597 IPv6MaskLen: Mask Length. 599 PDAddr: PD address. 601 PDMaskLen: PD Mask Length. 603 VRF: Identifier of VRF. 605 4.2.1.4. QoS Information Model 607 In CU separation BNG information model, the Control-Plane (CP) 608 generates the QOS Table base on managed UP's bandwidth resources and 609 specific QoS requirements of user's services. This table may 610 contains a set of QoS matching rules. The CP sends this table to UP, 611 UP receives and parses this table, matches corresponding QoS rules 612 presented in the table, and then performs corresponding actions. 614 The Figure below illustrates the QoS Table of User-Plane: 616 +---CP: (generate Tables, which including several rules) 617 | 618 +---PORT-infor 619 | 620 +--- UserId 621 | 622 +--- QosSubCarCir 623 | 624 +--- QosSubCarPir 625 | 626 +--- QosSubCarCbs 627 | 628 +--- QosSubCarPbs 630 UserId: Identifier of user. 632 QosSubCarCir: Committed Information Rate. 634 QosSubCarPir: Peak information rate. 636 QosSubCarCbs:Committed Burst Size. 638 QosSubCarPbs:Peak Burst Size. 640 4.2.1.5. Traffic Statistics Infor 642 Another role of User-Plane is to report the available network 643 resources and statistical information. This section describes the 644 information model of UP's traffic statistics report. The User-Plane 645 captures run time traffic statistics, generates the traffic- 646 statistics infor table, and then reports it to Control-Plane. 648 The Figure below illustrates the Traffic Statistics Infor Table of 649 User-Plane: 651 +---UP:(report Traffic statistics) 652 | 653 +---UP-Traffic statistics 654 | 655 +--- UserID 656 | 657 +--- StatisticsType 658 | 659 +--- IngressStatisticsPackets 660 | 661 +--- IngressStatisticsBytes 662 | 663 +--- EngressStatisticsPackets 664 | 665 +--- EngressStatisticsBytes 667 UserID: The Identifier of User. 669 StatisticsType: Traffic types such as IPv4, IPv6. 671 IngressStatisticsPackets: Ingress Statistics Packets 673 IngressStatisticsBytes: Ingress Statistics Bytes. 675 EngressStatisticsPackets: Engress Statistics Packets 677 EngressStatisticsBytes: Engress Statistics Bytes. 679 4.2.2. Port Related Information 681 4.2.2.1. Port Information Model 683 The Port is a logical construct that identifies a specific process or 684 a type of network service. In CU separation BNG information model, 685 the Control-Plane (CP) generate the Port-Infor table base on the 686 port-resources, which are received from the User-Plane (UP), and the 687 specific requirements of user's services. This table contains a set 688 of Port's matching rules. And then the CP sends this Port-Infor to 689 UP 691 The Figure below illustrates the Port Information Table of User- 692 Plane: 694 +---CP: (generate tables, which contains several rules) 695 | 696 +---PORT-infor 697 | 698 +---IfIndex 699 | 700 +---BasEn 702 IfIndex: Index for interface. 704 BasEn: Enable the Bas Port. 706 4.2.2.2. Port Resources of UP 708 Another role of User-Plane is to report the available network 709 resources and statistical information. This section describes the 710 information model of UP's port resources report. The User-Plane 711 looks up the available ports, reports them to the Control-Plane. The 712 Control-Plane can generate Port-Infor table base on these information 713 and specific requirements of user's services. 715 The Figure below illustrates the Port Resources Information Table of 716 User-Plane: 718 +---UP:(report network resources) 719 | 720 +---UP-PORT-RESOURCES 721 | 722 +---IfIndex 723 | 724 +---IfName 725 | 726 +---IfType 727 | 728 +---LinkType 729 | 730 +---MacAddr 731 | 732 +---IfPhyState 733 | 734 +---MTU 736 IfIndex: The Index of interface. 738 IfName: The name of interface. 740 IfType: The interface type. 742 LinkType: The link type. 744 MacAddr: The Mac address. 746 IfPhyState: The physical state of the interface. 748 MTU: Maximum Transmission Unit. 750 4.2.3. Device Related Information 752 4.2.3.1. Address field distribute Table 754 In CU separation BNG information model, the Control-Plane (CP) 755 generates and sends this Address field distribute Information table 756 to UP. The UP receives and parses this table, matches corresponding 757 rules presented in Address-field-distribute, and then performs 758 actions 760 The Figure below illustrates the Address field distribute Table of 761 User-Plane: 763 +---UP:(match rules then perform corresponding actions) 764 | 765 +---PORT-infor 766 | 767 +---AddressSegment 768 | 769 +---AddressSegmentMask 770 | 771 +---AddressSegmentVrf 772 | 773 +---NextHop 774 | 775 +---IfIndex 776 | 777 +---MaskLen 779 AddressSegment: The address segment information. 781 AddressSegmentMask: The address segment mask information. 783 AddressSegmentVrf: The address segment VRF. 785 NextHop: The next hop. 787 IfIndex: The index of the outing interface. 789 MaskLen: The Mask length. 791 5. Security Considerations 793 None. 795 6. IANA Considerations 797 None. 799 7. Normative References 801 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 802 Requirement Levels", BCP 14, RFC 2119, 803 DOI 10.17487/RFC2119, March 1997, 804 . 806 Authors' Addresses 808 Michael Wang (editor) 809 Huawei 810 101 Software Avenue, Yuhua District 811 Nanjing, Jiangsu 210012 812 China 814 Email: wangzitao@huawei.com 816 Jie Chen 817 Huawei 818 101 Software Avenue, Yuhua District 819 Nanjing, Jiangsu 210012 820 China 822 Email: chenjie@huawei.com 824 Rong Gu 825 China Mobile 826 32 Xuanwumen West Ave, Xicheng District 827 Beijing, Beijing 100053 828 China 830 Email: gurong_cmcc@outlook.com