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Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NFVRG S. Jeon 3 Internet-Draft Y. Kim 4 Intended status: Informational Soongsil University 5 Expires: January 4, 2019 July 3, 2018 7 Use Cases and Requirements for Dynamic Slice Stitching 8 draft-sijeon-nfvrg-slice-stitching-00.txt 10 Abstract 12 This document describes use cases and requirements for dynamic slice 13 stitching. 15 Status of This Memo 17 This Internet-Draft is submitted in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at https://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on January 4, 2019. 32 Copyright Notice 34 Copyright (c) 2018 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (https://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Table of Contents 49 1. Overview and Use Cases . . . . . . . . . . . . . . . . . . . 2 50 2. Requirements for Dynamic Slice Stitching . . . . . . . . . . 5 51 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 52 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 53 5. Informative References . . . . . . . . . . . . . . . . . . . 6 54 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 56 1. Overview and Use Cases 58 Network slicing means that a communication network is divided into 59 multiple, logical end-to-end networks (slices), all sharing the same 60 physical network infrastructure [_3GPP.23.501]. Multiple services 61 belonging to different service categories such as eMBB, massive IoT, 62 mission-critical IoT can be supported by different slices. Network 63 slicing does not remain multiple services support with virtualization 64 effect but the potential is with beyond regional domain boundary for 65 global vertical industry service. 67 A vertical industry service may remain in a single operator domain or 68 require multiple domains operated by the same network/service 69 providers. In the multiple domain scenario, network slices created 70 from each domain should be federated and associated. We call it 71 'slice stitching'. In the design phase, slice stitching can be 72 treated and handled by network slice description that defines overall 73 characteristics of the network slice with types of service function, 74 link connectivity between network functions, resource of each service 75 function and link, etc. 77 The need of slice stitching could be found in load balancing, 78 differentiated WAN services with more bandwidth and advanced 79 middlebox support, security-enhanced purpose on demand, which can be 80 provided by dynamic instantiation of a new slice and interconnection 81 among the existing ones. In addition, one very interesting use case 82 can be found in providing virtualized home domain service support 83 with low latency in a visited roaming domian. The dynamic slice 84 stitching can be illustrated and explained by high-level operations 85 in Figs. 1 and 2. (a), (b), (c) in Figs. 1 and 2 denote the order of 86 the operations in each figure. 88 ========== ========== 89 = = = = 90 -- = A = -------------------------------- = B = -- 91 = = = = 92 ========== ========== 94 (a) Slices A and B interconnected 96 ========== ========== 97 = = = = 98 -- = A = -------------------------------- = B = -- 99 = = ========== = = 100 ========== = = ========== 101 = C = 102 = = 103 ========== 105 (b) Slices A and B interconnected, and Slice C is created 106 but not interconnected with Slices A and B 108 ========== ========== 109 = = = = 110 -- = A = --+--------------------------+-- = B = -- 111 = = \ ========== / = = 112 ========== \ = = / ========== 113 +-- = C = --+ 114 = = 115 ========== 117 (c) Slices A and C interconnected with Slice B 119 Figure 1: High-Level Operation Scenario of Dynamic Slice Stitching 120 for New Slice Stitching 122 Fig. 1 describes an operation operation for new slice stitching. In 123 Fig. 1 (a), Slices A and B are connected, where each slice is 124 instantiated at different domains operated by the same operator. In 125 Fig. 1 (b), Slice C is created and instantiated for differentiated 126 WAN service support with high availability and reliability by 127 following one of the needs explained above. One thing to notice here 128 is, Slice C is not connected with Slice A and Slice B. In Fig. 1 129 (c), Slice C is interconnected with Slices A and B, so a tenant with 130 premium connection demand/subscription can be served by Slices A, C, 131 B, while Slice A and Slice B serve on-going service sessions. 133 ========== ========== ========== 134 = = = = = = 135 -- = A = -------- = B = -------- = C = -- 136 = = = = = = 137 ========== ========== ========== 139 (a) Slices A and C interconnected with Slice B 141 ========== 142 = = 143 +-- = B = --+ 144 ========== / = = \ ========== 145 = = / ========== \ = = 146 -- = A = --+ +-- = C = -- 147 = = ========== = = 148 ========== = = ========== 149 = B' = 150 = = 151 ========== 153 (b) Slices A and C interconnected with Slice B, and 154 newly created Slice B' but not interconnected with other slices 156 ========== 157 = = 158 +-- = B = --+ 159 ========== / = = \ ========== 160 = = / ========== \ = = 161 -- = A = --+ +-- = C = -- 162 = = \ ========== / = = 163 ========== \ = = / ========== 164 +-- = B' = --+ 165 = = 166 ========== 168 (c) Slices A and C interconnected with Slice B and Slice B' 170 Figure 2: High-Level Operation Scenario of Dynamic Slice Stitching 171 for Additional Slice Stitching 173 Another operation scenario for dynamic slice stitching can be found 174 in additional slice creation and interconnection illustrated in Fig. 175 2. In Fig. 2 (a), Slices A, B, C are interconnected, where each 176 slice is instantiated at different domains operated by the same 177 operator. In Fig. 2 (b), Slice B' is created for security-enhanced 178 support by following one of the needs explained above. One thing to 179 notice here is, Slices A and C are not interconnected each other. In 180 Fig. 2 (c), Slice B' is federated with Slices A and C, so a tenant 181 with premium connection demand/subscription can be served by Slices 182 A, B', C. 184 This document describes requirements for dynamic slice stitching 185 explained in Figs. 1 and 2. From the requirements, we check current 186 available approaches and measures. 188 2. Requirements for Dynamic Slice Stitching 190 Dynamic slice stitching basically requires interconnection between 191 Slice A and B(B'), Slice B(B') and C. The interconnection should be 192 made at network resource level to meet required connectivity demand 193 in the end-to-end connection perspective. The interconnection also 194 includes function level, so chaining of service functions between 195 Slice A and B(B'), Slice B(B') and C should dynamically be made. 197 1) Resource stitching between slices 199 Suppose that Slice A and Slice B in Fig. 1 were configured with 100 200 Mbps bandwidth and 100 ms latency in end-to-end connection. When 201 Slice C is interconnected with Slice A and Slice B, to meet the same 202 or better performance for service sessions going through Slice A, 203 Slice C, Slice B in order, dynamic adjustment such as scaling up/down 204 of existing resouce assigned in Slice A to Slice B could be required. 205 The resource adjustment and reconfiguration may also happen in Fig. 206 2. 208 2) Service function stitching between slices 210 Suppose that each slice is composed of one or more service functions 211 and the service functions in each slice need to be stitched for end- 212 to-end service. Service functions should dynamically chained. When 213 it comes Service Function Chaining (SFC) with the Network Service 214 Header (NSH) approach or routing controller, dynamic calculation of 215 chaining should be orchestrated by the multi-domain slice 216 orchestrator and configuration should be made at proper entity such 217 as NSH classifier or dataplane node. However, such approach may 218 bring about chaining scalability issue with chaining burden. 219 Isolating SF chaining list per slice with such as hierarchical SFC 220 (hSFC) could be effective and efficient for smooth operation support 221 in the function stitching [I-D.ietf-sfc-hierarchical]. 223 3. IANA Considerations 225 This document does not require any IANA actions. 227 4. Security Considerations 229 This document does not have security considerations. 231 5. Informative References 233 [_3GPP.23.501] 234 3GPP, "System Architecture for the 5G System", 3GPP 235 TS 23.501 15.0.0, December 2018, 236 . 238 [I-D.ietf-sfc-hierarchical] 239 Dolson, D., Homma, S., Lopez, D., and M. Boucadair, 240 "Hierarchical Service Function Chaining (hSFC)", draft- 241 ietf-sfc-hierarchical-11 (work in progress), June 2018. 243 Authors' Addresses 245 Seil Jeon 246 Soongsil University 247 369 Sangdo-ro, Dongjak-gu 248 Seoul 249 Korea 251 Email: sijeon@dcn.ssu.ac.kr 253 Younghan Kim 254 Soongsil University 255 369 Sangdo-ro, Dongjak-gu 256 Seoul 257 Korea 259 Email: younghak@ssu.ac.kr