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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group X. Geng 3 Internet-Draft J. Dong 4 Intended status: Informational Huawei Technologies 5 Expires: August 26, 2021 R. Pang 6 China Unicom 7 L. Han 8 China Mobile 9 T. Niwa 10 Individual 11 J. Jin 12 LG U+ 13 C. Liu 14 China Unicom 15 N. Nageshar 16 Individual 17 February 22, 2021 19 5G End-to-end Network Slice Mapping from the view of Transport Network 20 draft-geng-teas-network-slice-mapping-03 22 Abstract 24 Network Slicing is one of the core featrures in 5G. End-to-end 25 network slice consists of 3 major types of network segments: Access 26 Network (AN), Mobile Core Network (CN) and Transport Network (TN). 27 This draft describes the procedure of mapping 5G end-to-end network 28 slice to transport network slice defined in IETF. This draft also 29 intends to expose some gaps in the existing network management plane 30 and data plane technologies to support inter-domain network slice 31 mapping. Further work may require cooperation between IETF and 3GPP 32 (or other standard organizations). Data model specification, 33 signaling protocol extension and new encapsulation definition are out 34 of the scope of this draft. 36 Requirements Language 38 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 39 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 40 document are to be interpreted as described in RFC 2119 [RFC2119]. 42 Status of This Memo 44 This Internet-Draft is submitted in full conformance with the 45 provisions of BCP 78 and BCP 79. 47 Internet-Drafts are working documents of the Internet Engineering 48 Task Force (IETF). Note that other groups may also distribute 49 working documents as Internet-Drafts. The list of current Internet- 50 Drafts is at https://datatracker.ietf.org/drafts/current/. 52 Internet-Drafts are draft documents valid for a maximum of six months 53 and may be updated, replaced, or obsoleted by other documents at any 54 time. It is inappropriate to use Internet-Drafts as reference 55 material or to cite them other than as "work in progress." 57 This Internet-Draft will expire on August 26, 2021. 59 Copyright Notice 61 Copyright (c) 2021 IETF Trust and the persons identified as the 62 document authors. All rights reserved. 64 This document is subject to BCP 78 and the IETF Trust's Legal 65 Provisions Relating to IETF Documents 66 (https://trustee.ietf.org/license-info) in effect on the date of 67 publication of this document. Please review these documents 68 carefully, as they describe your rights and restrictions with respect 69 to this document. Code Components extracted from this document must 70 include Simplified BSD License text as described in Section 4.e of 71 the Trust Legal Provisions and are provided without warranty as 72 described in the Simplified BSD License. 74 Table of Contents 76 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 77 2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3 78 3. Network Slice Mapping Structure . . . . . . . . . . . . . . . 4 79 3.1. Requirements Profile . . . . . . . . . . . . . . . . . . 5 80 3.2. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 6 81 3.3. Relevant functions . . . . . . . . . . . . . . . . . . . 6 82 4. Network Slice Mapping Procedure . . . . . . . . . . . . . . . 7 83 4.1. Network Slice Mapping in Management Plane . . . . . . . . 8 84 4.2. Network Slice Mapping in Control Plane . . . . . . . . . 9 85 4.3. Network Slice Mapping in Data Plane . . . . . . . . . . . 10 86 4.3.1. Data Plane Mapping Considerations . . . . . . . . . . 10 87 4.3.2. Data Plane Mapping Options . . . . . . . . . . . . . 10 88 5. Network Slice Mapping Summary . . . . . . . . . . . . . . . . 15 89 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 90 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 91 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 92 9. Normative References . . . . . . . . . . . . . . . . . . . . 16 93 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 95 1. Introduction 97 Driven by the new applications of 5G, the concept of network slicing 98 is defined to provide a logical network with specific capabilities 99 and characteristics. Network slice contains a set of network 100 functions and allocated resources(e.g. computation, storage and 101 network resources). According to [TS28530], a 5G end-to-end network 102 slice is composed of three major types network segments: Radio Access 103 Network (RAN), Transport Network (TN) and Mobile Core Network (CN). 104 Transport network is supposed to provide the required connectivity 105 between AN and CN, with specific performance commitment. For each 106 end-to-end network slice, the topology and performance requirement 107 for transport network can be very different, which requests transport 108 network to have the capability of supporting multiple different 109 transport network slices. 111 A transport network slice is a virtual (logical) network with a 112 particular network topology and a set of shared or dedicated network 113 resources, which are used to provide the network slice consumer with 114 the required connectivity, appropriate isolation and specific Service 115 Level Agreement (SLA). A transport network slice could span multiple 116 technology (IP, Optical) and multiple administrative domains. 117 Depending on the consumer's requirement, a transport network slice 118 could be isolated from other concurrent transport network slices, in 119 terms of data plane, control plane and management plane. Transport 120 network slice is being defined and discussed in IETF. 122 Editor's Note: The definition of transport network slice will align 123 with [I-D.ietf-teas-ietf-network-slice-definition]. 125 The procedure of end-to-end network slice instance creation, network 126 slice subnet instance creation and network slice instance termination 127 in management plane is defined in [TS28531]. The end-to-end network 128 slice allocation is defined in ETSI [ZSM003]. But there is no 129 specifications about how to map end-to-end network slice in 5G system 130 to transport network slice. This draft describes the procedure of 131 mapping 5G end-to-end network slice into transport network slice in 132 management plane, control plane and user plane. 134 5G end-to-end network slice mapping is treated as an independent 135 mechanism from 5G end-to-end QoS mapping. The latter is not covered 136 by this version. 138 2. Terminologies 140 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 141 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 142 document are to be interpreted as described in [RFC2119]. 144 The following terms are used in this document: 146 NS: Network Slice 148 NSI: Network Slice Instance 150 NSSI: Network Slice Subnet Instance 152 NSSAI: Network Slice Selection Assistance Information 154 S-NSSAI: Single Network Slice Selection Assistance Information 156 AN: Access Network 158 RAN: Radio Access Network 160 TN: Transport Network 162 CN: Mobile Core Network 164 DSCP: Differentiated Services Code Point 166 CSMF: Communication Service Management Function 168 NSMF: Network Slice Management Function 170 NSSMF: Network Slice Subnet Management Function 172 GST: General Slice Template 174 TNSII: Transport Network Slice Interworking Identifier 176 TNSI: Transport Network Slice Identifier 178 PDU: Protocol Data Unit 180 Editor's Note: Terminologies defined in 3GPP, e.g.,Network Slice 181 Subnet Management Function(NSSMF), Network Slice Subnet 182 Instance(NSSI) and Network Slice Selection Assistance 183 Information(NSSAI), are used in the end-to-end network slice mapping, 184 which may not be used necessarily within the transport network. 186 3. Network Slice Mapping Structure 188 The following figure shows the necessary elements for mapping end-to- 189 end network slice into transport network slice. All these network 190 slice elements are classified into three groups: requirements/ 191 capabilities, identifiers and relevant functions. 193 +-----------------+ 194 | CSMF | 195 +--------+--------+ 196 | 197 +--------V--------+ 198 | NSMF | 199 +-----------------+ 200 +----------| NSI Identifier |----------+ 201 | | Service Profile | | 202 | | TN Network- | | 203 | | -Slice Profile | | 204 | +-----------------+ | 205 | | | 206 +------V------+ +----------V----------+ +------V------+ 207 | AN NSSMF | | TN NSSMF | | CN NSSMF | 208 +-------------+ +---------------------+ +-------------+ 209 | AN-NSSI- | | TN-NSSI Identifier | | CN-NSSI- | 210 | -Identifier | | Function Management| | -Identifier | 211 | ... | | ... | | ... | Management 212 +-------------+ +---------------------+ +-------------+ Plane 213 | | | | ----------------- 214 |<----------PDU session (S-NSSAI)---------->| Control 215 | | | | Plane 216 V V V V ----------------- 217 /\ +-----+ +-----+ +-------+ Data 218 /AN\ -----| PE |-----...-----| PE |----| UPF | Plane 219 /____\ +-----+ +-----+ +-------+ 220 |-->TNSII<--|------>TNSI<-------|-->TNSII<--| 222 3.1. Requirements Profile 224 In order to satisfy a tenant's request for a network slice with 225 certain characteristics, creating a new network slice or using 226 existing network slice instance is constrained by the requirement 227 profile and the capability of the network slices. 229 o Service Profile: represents the properties of network slice 230 related requirement that should be supported by the network slice 231 instance in 5G network. Service profile is defined in [TS28541] 232 6.3.3. 234 o TN Network Slice Profile: represents the properties of transport 235 network slice related requirement that should be supported by the 236 transport network slice in a 5G network. Slice Profile is defined 237 in [TS28541] 6.3.4. TN Network slice profile is newly defined in 238 this draft. 240 3.2. Identifiers 242 Network slice related identifiers in management plane, control plane 243 and data(user) plane play an important role in end-to-end network 244 slice mapping. 246 o Single Network Slice Selection Assistance Information(S-NSSAI): 247 end-to-end network slice identifier in control plane, which is 248 defined in [TS23501]; 250 o Network Slice Instance(NSI) Identifier:end-to-end network slice 251 identifier in management plane, which is created in NSMF; NSI is 252 is set of Network Function instances and the required resources 253 (e.g. computing, storage and networking resources) which form a 254 deployed Network Slice, which is defined in [TS23501]; ; 256 o Transport Network Slice Instance(TN-NSSI) Identifier: transport 257 network slice identifier in management plane, which is created in 258 TN NSSMF; TN-NSSI is newly defined in this draft. 260 o Transport Network Slice Interworking Identifier (TNSII): network 261 slice identifier which is used for mapping end-to-end network 262 slice into transport network slice in data plane. TNSII is a new 263 concept introduced by this draft, which can be instantiated with 264 existing data plane identifiers and doesn't necessarilly request 265 new encapsulation. TNSII could be pre-allocated as a global 266 identifier. 268 o Transport Network Slice Identifier(TNSI): transport network slice 269 identifier in data plane(user plane). TNSI is newly defined in 270 this draft. 272 The relationship between these identifiers are specifies in the 273 following sections. 275 3.3. Relevant functions 277 There are a set of slice relevant functions that are necessary for 278 transport network slice management: 280 o Topology management 282 o QoS management 284 o Resource management 286 o Measurement management 287 o ... 289 Some of these functions are implemented inside the transport network 290 and independent from the end-to-end network slice, e.g., topology 291 management, QoS management, resource management; Some of the 292 functions are related to the end-to-end network slice and should 293 cooperate with other network elements from other domain, e.g., 294 Measurement management. 296 4. Network Slice Mapping Procedure 298 This section provides a general procedure of network slice mapping: 300 +--------------------------------+ 301 | Requirement Matching | 302 +---------------+----------------+ 303 | 304 V 305 +--------------------------------+ 306 | NSI<->TN NSSI Mapping | 307 +---------------+----------------+ 308 | 309 V 310 +--------------------------------+ 311 | S-NSSAI Selection | 312 +---------------+----------------+ 313 | 314 V 315 +--------------------------------+ 316 |S-NSSAI<---------->TNSII Mapping| 317 | (NSI<->TN NSSI) | 318 +---------------+----------------+ 319 | 320 V 321 +--------------------------------+ 322 | TNSII<->TNSI Mapping | 323 +--------------------------------+ 325 1. NSMF receives the request from CSMF for allocation of a network 326 slice instance with certain characteristics. 328 2. Based on the service requirement , NSMF acquires requirements for 329 the end-to-end network slice instance , which is defined in Service 330 Profile([TS28541] section 6.3.3). 332 3. NSMF derives transport network slice related requirements from 333 the Service profile, and maintains them in Transport Network Slice 334 Profile, So as to CN Slice Profile and AN Slice Profile, in order to 335 decide on the constituent NSSIs(including AN NSSI, CN NSSI and TN 336 NSSI) of the NSI, based on the service profile and the endpoint 337 information(AN/CN edge nodes). 339 4. NSMF sends the Transport Network Slice Profile, endpoint 340 information, along with other TS NBI attributes to TN NSSMF for TN 341 NSSI allocation. 343 5. TN NSSMF allocates TN NSSI which could satisfy the requirement of 344 Transport Network Slice Profile between the specified endpoints (AN/ 345 CN edge nodes) and sends the TN NSSI Identifier to NSMF. 347 6. NSMF acquires the mapping relationship between NSI and TN NSSI. 349 7. NSMF matains the mapping relationship between NSI and S-NSSAI and 350 the mapping relationship between TN NSSI and TNSII, which could be 351 used to set up mapping relationship between S-NSSAI and TNSII. 353 8. When a PDU session is set up between AN and CN, an S-NSSAI is 354 selected for the PDU session. 356 9. AN/CN edge nodes encapsulates the packet using TNSII, according 357 to the selected S-NSSAI. Network Slice could also be differentiated 358 by physical interface, if different network slices are transported 359 through different interface; 361 10. The edge node of transport network parses the TNSII from the 362 packet and maps the packet to the corresponding transport network 363 slice. It may encapsulate packet with TNSI. The nodes in transport 364 network transit the packet inside the corresponding transport network 365 slice according to TNSI. 367 The procedure of end-to-end network slice mapping involves the 368 mapping in three network planes: management plane, control plane and 369 data plane. 371 4.1. Network Slice Mapping in Management Plane 373 The transport network management Plane maintains the interface 374 between NSMF and TN NSSMF, which 1) guarantees that transport network 375 slice could connect the AN and CN with specified characteristics that 376 satisfy the requirements of communication; 2) builds up the mapping 377 relationship between NSI identifier and TN NSSI identifier; 3) 378 maintains the end-to-end slice relevant functions; 380 Service Profile defined in[TS28541] represents the requirement of 381 end-to-end network slice instance in 5G network. Parameters defined 382 in Service Profile include Latency, resource sharing level, 383 availability and so on. How to decompose the end-to-end requirement 384 to the transport network requirement is one of the key issues in 385 Network slice requirement mapping. GSMA(Global System for Mobile 386 Communications Association) defines the [GST] to indicate the network 387 slice requirement from the view of service provider. 388 [I-D.contreras-teas-slice-nbi] analysis the parameters of GST and 389 categorize the parameters into three classes, including the 390 attributes with direct impact on the transport network slice 391 definition. It is a good start for selecting the transport network 392 relevant parameters in order to define Network Slice Profile for 393 Transport Network. Network slice requirement parameters are also 394 necessary for the definition of transport network northbound 395 interface. 397 Inside the TN NSSMF, it is supposed to maintain the attributes of the 398 transport network slice. If the attributes of an existing TN NSSI 399 could satisfy the requirement from TN Network Slice Profile, the 400 existing TN NSSI could be selected and the mapping is finished If 401 there is no existing TN NSSI which could satisfy the requirement, a 402 new TN NSSI is supposed to be created by the NSSMF with new 403 attributes. 405 TN NSSI resource reservation should be considered to avoid over 406 allocation from multiple requests from NSMF (but the detailed 407 mechanism should be out of scope in the draft) 409 TN NSSMF sends the selected or newly allocated TN NSSI identifier to 410 NSMF. The mapping relationship between NSI identifier and TN NSSI 411 identifier is maintained in both NSMF and TN NSSMF. 413 YANG data model for the Transport Slice NBI, which could be used by a 414 higher level system which is the Transport slice consumer of a 415 Transport Slice Controller (TSC) to request, configure, and manage 416 the components of a transport slices, is defined in 417 [I-D.wd-teas-transport-slice-yang]. The northbound Interface of IETF 418 network slice refers to [I-D.wd-teas-ietf-network-slice-nbi-yang]. 420 4.2. Network Slice Mapping in Control Plane 422 There is no explicit interaction between transport network and AN/CN 423 in the control plane, but the S-NSSAI defined in [TS23501] is treated 424 as the end-to-end network slice identifier in the control plane of AN 425 and CN, which is used in UE registration and PDU session setup. In 426 this draft, we assume that there is mapping relationship between 427 S-NSSAI and NSI in the management plane, thus it could be mapped to a 428 transport network slice . 430 Editor's note: The mapping relationship between NSI defined in 431 [TS23501] and S-NSSAI defined in [TS23501] is still in discussion. 433 4.3. Network Slice Mapping in Data Plane 435 If multiple network slices are carried through one physical interface 436 between AN/CN and TN, transport network slice interworking 437 identifier(TNSII) in the data plane needs to be introduced. If 438 different network slices are transported through different physical 439 interfaces, Network Slices could be distinguished by the interface 440 directly. Thus TNSII is not the only option for network slice 441 mapping, while it may help in introducing new network slices. 443 4.3.1. Data Plane Mapping Considerations 445 The mapping relationship between AN or CN network slice identifier 446 (either S-NSSAI in control plane or NSI/NSSI in management plane) and 447 TNSII needs to be maintained in AN/CN network nodes, and the mapping 448 relationship between TNSII and TNSI is maintained in the edge node of 449 transport network. When the packet of a uplink flow goes from AN to 450 TN, the packet is encapsulated based on the TNSII; then the 451 encapsulation of TNSII is read by the edge node of transport network, 452 which maps the packet to the corresponding transport network slice. 454 Editor's Note: We have considered to add "Network Instance" defined 455 in [TS23501]in the draft. However, after the discussion with 3GPP 456 people, we think the concept of "network instance" is a 'neither 457 Necessary nor Sufficient Condition' for network slice. Network 458 Instance could be determined by S-NSSAI, it could also depends on 459 other information; Network slice could also be allocated without 460 network instance (in my understanding) And, TNSII is not a 461 competitive concept with network instance.TNSII is a concept for the 462 data plane interconnection with transport network, network instance 463 may be used by AN and CN nodes to associate a network slice with 464 TNSII 466 4.3.2. Data Plane Mapping Options 468 The following picture shows the end-to-end network slice in data 469 plane: 471 +--+ +-----+ +----------------+ 472 |UE|- - - -|(R)AN|---------------------------| UPF | 473 +--+ +-----+ +----------------+ 474 |<----AN NS---->|<----------TN NS---------->|<----CN NS----->| 476 The mapping between 3GPP slice and transport slice in user plane 477 could happens in: 479 (R)AN: User data goes from (radio) access network to transport 480 network 482 UPF: User data goes from core network functions to transport network 484 Editor's Note: As figure 4.7.1. in [TS28530] describes, TN NS will 485 not only exist between AN and CN but may also within AN NS and CN NS. 486 However, here we just show the TN between AN and CN as an example to 487 avoid unncessary complexity. 489 The following picture shows the user plane protocol stack in end-to- 490 end 5G system. 492 +-----------+ | | | 493 |Application+--------------------|------------------|---------------| 494 +-----------+ | | +-----------+ | 495 | PDU Layer +--------------------|------------------|-| PDU Layer | | 496 +-----------+ +-------------+ | +-------------+ | +-----------+ | 497 | | | ___Relay___ |--|--| ___Relay___ |-|-| | | 498 | | | \/ GTP-U|--|--|GTP-U\/ GTP-U|-|-| GTP-U | | 499 | 5G-AN | |5G-AN +------+ | +------+------+ | +-----------+ | 500 | Protocol | |Protoc|UDP/IP|--|--|UDP/IP|UDP/IP|-|-| UDP/IP | | 501 | Layers | |Layers+------+ | +------+------+ | +-----------+ | 502 | | | | L2 |--|--| L2 | L2 |-|-| L2 | | 503 | | | +------+ | +------+------+ | +-----------+ | 504 | | | | L1 |--|--| L1 | L1 |-|-| L1 | | 505 +-----------+ +-------------+ | +-------------+ | +-----------+ | 506 UE 5G-AN | UPF | UPF | 507 N3 N9 N6 509 The following figure shows the typical encapsulation in N3 interface 510 which could be used to carry the transport network slice interworking 511 identifier (TNSII) between AN/CN and TN. 513 +------------------------+ 514 | Application Protocols | 515 +------------------------+ 516 | IP (User) | 517 +------------------------+ 518 | GTP | 519 +------------------------+ 520 | UDP | 521 +------------------------+ 522 | IP | 523 +------------------------+ 524 | Ethernet | 525 +------------------------+ 527 4.3.2.1. Layer 3 and Layer 2 Encapsulations 529 If the encapsulation above IP layer is not visible to Transport 530 Network, it is not able to be used for network slice interworking 531 with transport network. In this case, IP header and Ethernet header 532 could be considered to provide information of network slice 533 interworking from AN or CN to TN. 535 +------------------------+----------- 536 | Application Protocols | ^ 537 +------------------------+ | 538 | IP (User) | Invisible 539 +------------------------+ for 540 | GTP | TN 541 +------------------------+ | 542 | UDP | V 543 +------------------------+------------ 544 | IP | 545 +------------------------+ 546 | Ethernet | 547 +------------------------+ 549 The following field in IP header and Ethernet header could be 550 considered : 552 IP Header: 554 o DSCP: It is traditionally used for the mapping of QoS identifier 555 between AN/CN and TN network. Although some values (e.g. The 556 unassigned code points) may be borrowed for the network slice 557 interworking, it may cause confusion between QoS mapping and 558 network slicing mapping.; 560 o Destination Address: It is possible to allocate different IP 561 addresses for entities in different network slice, then the 562 destination IP address could be used as the network slice 563 interworking identifier. However, it brings additional 564 requirement to IP address planning. In addition, in some cases 565 some AN or CN network slices may use duplicated IP addresses. 567 o Option fields/headers: It requires that both AN and CN nodes can 568 support the encapsulation and decapsulation of the options. 570 Ethernet header 572 o VLAN ID: It is widely used for the interconnection between AN/CN 573 nodes and the edge nodes of transport network for the access to 574 different VPNs. One possible problem is that the number of VLAN 575 ID can be supported by AN nodes is typically limited, which 576 effects the number of transport network slices a AN node can 577 attach to. Another problem is the total amount of VLAN ID (4K) 578 may not provide a comparable space as the network slice 579 identifiers of mobile networks. 581 Two or more options described above may also be used together as the 582 TNSII, while it would make the mapping relationship more complex to 583 maintain. 585 In some other case, when AN or CN could support more layer 3 586 encapsulations, more options are available as follows: 588 If the AN or CN could support MPLS, the protocol stack could be as 589 follows: 591 +------------------------+----------- 592 | Application Protocols | ^ 593 +------------------------+ | 594 | IP (User) | Invisible 595 +------------------------+ for 596 | GTP | TN 597 +------------------------+ | 598 | UDP | V 599 +------------------------+------------ 600 | MPLS | 601 +------------------------+ 602 | IP | 603 +------------------------+ 604 | Ethernet | 605 +------------------------+ 607 A specified MPLS label could be used to as a TNSII. 609 If the AN or CN could support SRv6, the protocol stack is as follows: 611 +------------------------+----------- 612 | Application Protocols | ^ 613 +------------------------+ | 614 | IP (User) | Invisible 615 +------------------------+ for 616 | GTP | TN 617 +------------------------+ | 618 | UDP | V 619 +------------------------+------------ 620 | SRH | 621 +------------------------+ 622 | IPv6 | 623 +------------------------+ 624 | Ethernet | 625 +------------------------+ 627 The following field could be considered to identify a network slice: 629 SRH: 631 o SRv6 functions: AN/CN is supposed to support the new function 632 extension of SRv6. 634 o Optional TLV: AN/CN is supposed to support the extension of 635 optional TLV of SRH. 637 4.3.2.2. Above Layer 3 Encapsulations 639 If the encapsulation above IP layer is visible to Transport Network, 640 it is able to be used to identify a network slice. In this case, UPD 641 and GTP-U could be considered to provide information of network slice 642 interworking between AN or CN and TN. 644 +------------------------+---------- 645 | Application Protocols | | 646 +------------------------+ Invisible 647 | IP (User) | for 648 +------------------------+ TN 649 | GTP | | 650 +------------------------+------------ 651 | UDP | 652 +------------------------+ 653 | IP | 654 +------------------------+ 655 | Ethernet | 656 +------------------------+ 657 The following field in UDP header could be considered: 659 UDP Header: 661 o UDP Source port: The UDP source port is sometimes used for load 662 balancing. Using it for network slice mapping would require to 663 disable the load-balancing behavior. 665 5. Network Slice Mapping Summary 667 The following picture shows the mapping relationship between the 668 network slice identifier in management plane, control plane and user 669 plane. 671 AN/CN | TN 672 Management +---------+ | +---------+ 673 Plane | NSI |<--------|------->| TN NSSI | 674 +---------+ | +---------+ 675 | | | 676 | | | 677 Control +-----V-----+ | +----------+----------+ 678 Plane | S-NSSAI | | | | 679 +-----------+ | | | 680 | +----V----+ +----V----+ 681 +----------->| TNSII |<--------->| TNSI | 682 User | /Port |<--------->| | 683 Plane +---------+ +---------+ 685 6. IANA Considerations 687 TBD 689 Note to RFC Editor: this section may be removed on publication as an 690 RFC. 692 7. Security Considerations 694 TBD 696 8. Acknowledgements 698 The authors would like to thank Shunsuke Homma for reviewing the 699 draft and giving valuable comments. 701 9. Normative References 703 [GST] "Generic Network Slice Template", 704 . 707 [I-D.contreras-teas-slice-nbi] 708 Contreras, L., Homma, S., and J. Ordonez-Lucena, "IETF 709 Network Slice use cases and attributes for Northbound 710 Interface of controller", draft-contreras-teas-slice- 711 nbi-03 (work in progress), October 2020. 713 [I-D.ietf-teas-ietf-network-slice-definition] 714 Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J. 715 Tantsura, "Definition of IETF Network Slices", draft-ietf- 716 teas-ietf-network-slice-definition-00 (work in progress), 717 January 2021. 719 [I-D.wd-teas-ietf-network-slice-nbi-yang] 720 Bo, W., Dhody, D., Han, L., and R. Rokui, "A Yang Data 721 Model for IETF Network Slice NBI", draft-wd-teas-ietf- 722 network-slice-nbi-yang-01 (work in progress), November 723 2020. 725 [I-D.wd-teas-transport-slice-yang] 726 Bo, W., Dhody, D., Han, L., and R. Rokui, "A Yang Data 727 Model for Transport Slice NBI", draft-wd-teas-transport- 728 slice-yang-02 (work in progress), July 2020. 730 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 731 Requirement Levels", BCP 14, RFC 2119, 732 DOI 10.17487/RFC2119, March 1997, 733 . 735 [TS23501] "3GPP TS23.501", 736 . 739 [TS28530] "3GPP TS28.530", 740 . 743 [TS28531] "3GPP TS28.531", 744 . 747 [TS28541] "3GPP TS 28.541", 748 . 751 [ZSM003] "ETSI ZSM003", 752 . 755 Authors' Addresses 757 Xuesong Geng 758 Huawei Technologies 760 Email: gengxuesong@huawei.com 762 Jie Dong 763 Huawei Technologies 765 Email: jie.dong@huawei.com 767 Ran Pang 768 China Unicom 770 Email: pangran@chinaunicom.cn 772 Liuyan Han 773 China Mobile 775 Email: hanliuyan@chinamobile.com 777 Tomonobu Niwa 778 Individual 780 Email: tomonobu.niwa@gmail.com 782 Jaehwan Jin 783 LG U+ 785 Email: daenamu1@lguplus.co.kr 786 Chang Liu 787 China Unicom 789 Email: liuc131@chinaunicom.cn 791 Nikesh Nageshar 792 Individual 794 Email: nikesh.nageshar@gmail.com