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Jeon 3 Internet-Draft Sungkyunkwan University 4 Intended status: Standards Track March 13, 2017 5 Expires: September 14, 2017 7 Stateless mobility functions 8 draft-sijeon-dmm-stateless-mobility-function-00.txt 10 Abstract 12 This draft presents two use cases to start a talk of stateless 13 mobility function architecture in IETF DMM WG. 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 http://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 September 14, 2017. 32 Copyright Notice 34 Copyright (c) 2017 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 (http://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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 50 2. Mobility function architecture . . . . . . . . . . . . . . . 3 51 2.1. Integrated state with mobility function . . . . . . . . . 3 52 2.2. Separated state from mobility function . . . . . . . . . 3 53 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 54 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 55 5. Informative References . . . . . . . . . . . . . . . . . . . 4 56 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 58 1. Introduction 60 A mobility function could be categorized stateful function and 61 stateless function. The stateful function maintains the state 62 information associated with a terminal or network situation while the 63 stateless function does not keep the state information but only 64 focusing on processing received signaling messages or data packets, 65 as a worker. 67 Combing the state with the worker in the mobility function has 68 basically been considered in many network architectures for easier 69 implementation and negligible latency for accessing the state 70 database without external signaling messages. However, it is 71 nowadays challenging as it tackles the flexibility for network 72 scaling and other enhanced operation support. 74 Separating the control-plane and user-plane makes a progress for the 75 flexible network control and provisioning. That is, a routing 76 controller with holistic view can take a decision of forwarding 77 behavior in the network entities. Stateless user-plane architecture 78 is proposed in [I-D.matsushima-stateless-uplane-vepc], suggesting a 79 mobile architecture that the user-plane network is governed by 80 virtualized EPC decorated with mobility control-plane functions only. 81 The state information the vEPC is holding is transferred by BGP 82 routing to the user-plane architecture. Therefore, the user-plane 83 architecture is totally abstracted and becomes state free, supporting 84 high flexibility in network scaling. 86 Mobility architecture is composed of many control-plane functions. 87 Scale-in/scale-out of those functions is of importance for elastic 88 function resource handling and management (e.g., load balancing). 89 User-plane functions does not generically hold the state information 90 much, so it is relatively easier to do scaling but it is challenging 91 to scale with mobility control-plane functions. Separating the state 92 information from the control-plane functions could facilitate 93 flexible function resource provisioning and expect further enhanced 94 scenarios such as VNF mobility and migration procedure easier. 96 The main objective of this draft is to bring a broad discussion in 97 IETF DMM WG, identifying what needs and requirements for the state 98 separation from a mobility function are existing and what use cases 99 could be meaningful, finally bearing a work item. In this draft, we 100 start with two cases; i) mobility control-plane function integrated 101 with the state information and ii) mobility control-plane function 102 separated from the state information. From the two cases, we check 103 the mentioned aspects. 105 2. Mobility function architecture 107 2.1. Integrated state with mobility function 109 Fig. 1 shows the state information is integrated in the mobility 110 control-plane function. Suppose that the mobility control-plane 111 function is composed of state and worker where the work is dedicated 112 to the processing of signaling messages or data packets without 113 concerning or maintaining the state. When the function is 114 instantiated, the state is also initialized within the function. On 115 the other hand, the function needs to be shut down due to some 116 maintenance purpose and the same kinds of a new function is supposed 117 to be initiated, the managed mobility state associated with mobile 118 terminals should be moved to the newly initiated mobility control- 119 plane function through a migration procedure in this case. 121 +-------------+ +-------------+ 122 | State info. | | State info. | 123 +-------------+ +-------------+ 124 | Worker for | | Worker for | 125 | MCP function| | MCP function| 126 +-------------+ +-------------+ 128 Fig. 1. The mobility function integrated with the state information 130 2.2. Separated state from mobility function 132 Fig. 2 shows the state information is separated from the mobility 133 control-plane function, thus the worker for mobility control-plane 134 function remains in the function. The relationship between the state 135 database and worker can be defined by internal interface or external 136 interface. Following the same scenario described in 2.1, for a need 137 of replacing with a new worker or for scaling out/in, maintaining the 138 state is not constrained, so facilitating various flexibility 139 scenarios. 141 +-------------+ 142 | State info. | 143 +-------------+ 144 | ^ ^ | 145 | | | | 146 v | | v 147 +-------------+ +-------------+ 148 | Worker for | | Worker for | 149 | MCP function| | MCP function| 150 +-------------+ +-------------+ 152 Fig. 2. The mobility function separated from the state information 154 3. IANA Considerations 156 This document currently makes no request of IANA. 158 4. Security Considerations 160 5. Informative References 162 [ETSI.NFV-VNFA] 163 "Network Functions Virtualisation (NFV); Virtual Network 164 Functions Architecture, ETSI GS NFV-SWA 001, v1.1.1", 165 Proceedings of GlobeCom Workshop on Seamless Wireless 166 Mobility, December 2014. 168 [I-D.matsushima-stateless-uplane-vepc] 169 Matsushima, S. and R. Wakikawa, "Stateless user-plane 170 architecture for virtualized EPC (vEPC)", draft- 171 matsushima-stateless-uplane-vepc-06 (work in progress), 172 March 2016. 174 Author's Address 176 Seil Jeon 177 Sungkyunkwan University 178 2066 Seobu-ro, Jangan-gu 179 Suwon, Gyeonggi-do 180 Korea 182 Email: seiljeon@skku.edu