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Wei 3 Internet-Draft Huawei Technologies 4 Intended status: Informational February 13, 2014 5 Expires: August 17, 2014 7 Consideration of Routing Optimization for DMM network 8 draft-wei-dmm-ro-consideration-00 10 Abstract 12 Distributed Mobility Management (DMM) is designed to be a distributed 13 and scalable mobility management solution, and providing optimal 14 route for traffics is one of DMM's aims. There have been several 15 proposals on DMM framework, and this document provides discussion on 16 how to optimize traffic routes, and aims to provide suggestioins on 17 how to avoid long route in DMM network. 19 Status of this Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on August 17, 2014. 36 Copyright Notice 38 Copyright (c) 2014 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 2. Terminology and Abbreviation . . . . . . . . . . . . . . . . . 4 55 2.1. Conventions Used in This Document . . . . . . . . . . . . 4 56 3. Impacts of routing optimization . . . . . . . . . . . . . . . 5 57 3.1. Tunneling . . . . . . . . . . . . . . . . . . . . . . . . 5 58 3.2. IP changing . . . . . . . . . . . . . . . . . . . . . . . 6 59 3.3. Local Routing . . . . . . . . . . . . . . . . . . . . . . 7 60 4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 9 61 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 62 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 63 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 64 7.1. Normative References . . . . . . . . . . . . . . . . . . . 12 65 7.2. Informative References . . . . . . . . . . . . . . . . . . 12 66 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 68 1. Introduction 70 The new network service scenarios such as network traffic offloading 71 and mobility service in local Content Delivery Networks (CDNs) impose 72 new requirements on network mobility management, and a more flat 73 mobility management system with fewer levels of routing hierarchy 74 introduced into the data path is more preferred. So Distributed 75 Mobility Management (DMM) is proposed to satisfy these new network 76 mobility management requirements, and DMM aims to solve the problems 77 such as non-optimal routes, poor network scalability, and single 78 point of failure and attack which are widely faced by existing 79 centralized mobility management protocols [4]. 81 Currently several solutions on DMM framework are being discussed, 82 some of the solutions are based on existing IP mobility management 83 protocols [5] [6], and others provide new solutions [7] [8]. These 84 solutions provide their own DMM frameworks, and in order to transport 85 traffic through an optimal path the basic idea of these solutions is 86 placing mobility anchors in a distributed way. 88 Routing redundancy is a common problem in mobile IP network. In 89 mobile IP network, Mobility Anchor (MA) acts as topological anchor of 90 IP address, and due to the existing of mobility anchors, the packets 91 sent from MN's Correspondent Node (CN) are always firstly routed to 92 MN's mobility anchor and then forwarded to MN. In order to reduce 93 routing redundancy problem existing in mobile IP network, some 94 routing optimization methods could be implemented. Because mobility 95 anchor will be existed in DMM network, so routing optimization 96 method(s) would also be taken into consideration in the design of DMM 97 network. 99 This document provides some considerations of routing optimization 100 related issues for the design of DMM network, several routing 101 optimization methods and their impacts on traffic will be discussed. 103 2. Terminology and Abbreviation 105 2.1. Conventions Used in This Document 107 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL 108 NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in 109 thisdocument are to be interpreted as described in [1]. 111 3. Impacts of routing optimization 113 This section analyzes the impacts of routing optimization on network 114 traffic. Several routing optimization methods, including tunneling, 115 changing the IP address and local routing, are discussed here. 117 3.1. Tunneling 119 In IP network, tunnel could be used to hide the network topology, and 120 it is a method of changing the route of traffic. Because tunnel can 121 let traffic travel in network without constrain of network topology, 122 so it is often used as a tool for changing the route of network 123 traffics. 125 In DMM network, MAs are distributed deployed and towards to access 126 network, it is likely for MN to attach to different MAs when MN moves 127 in the network. In order to keep service continuity, DMM network 128 would keep MN's IP address for IP session, and routes the packets 129 through the anchor of IP address. The change of MA would bring about 130 routing redundancy, so tunnel based routing optimization could be 131 used to reduce the routing redundancy. 133 For DMM network, When MN moves to a new MA, the tunnel for routing 134 optimization could be set up between MN's MA and CN's MA (Figure 1), 135 or between MN and CN (Figure 2). 137 +--+ 138 |CN| 139 +-|+ 140 | 141 | 142 +-|-+ 143 |MA3|=========|| 144 .'+---+ || 145 ,' || RO tunnel 146 / || 147 / || 148 +-`-+ +---+ 149 |MA1|--------------|MA2| 150 +-|-+ +-|-+ 151 | | 152 | | 153 | | 154 +|-+ +|-+ 155 |MN| ----------> |MN| 156 +--+ move +--+ 157 Figure1: tunnel based routing optimization 1 159 +--+ 160 +--------+|CN|=========|| 161 | +--+ || 162 | || 163 | || RO tunnel 164 | || 165 | || 166 | || 167 +---------+------------+ +-----||-------------+ 168 | ++--+ | | || | 169 | |MA1| | | || | 170 | +-+-+ | | || | 171 | | + | | || | 172 | ++-+ | | +--+ | 173 | |MN| -------------> |MN| | 174 | +--+ move | +--+ | 175 | | | | 176 +----------------------+ +--------------------+ 178 network of MA1 network of MA2 180 Figure2: tunnel based routing optimization 2 182 3.2. IP changing 184 In mobile IP network, the reason of non-optimal route is that in 185 order to provide service continuity for MN, network always guarantees 186 the consistency of MN's IP address when MN moves in network. But in 187 today's network there are a lot of applications that don't need 188 service continuity, e.g. web service, DNS; and for the applications 189 which though need service continuity, but they deal with service 190 continuity in other layers, e.g. application layer, transport layer 191 etc, and not depends on network layer. So for these applications, 192 the consistency of IP address will cause unnecessary non-optimal 193 route for them. 195 But for some other applications, they need mobility support from 196 network layer, and in order to keep service continuity the IP address 197 of MN must not be changed during the whole service session. 199 So in order to provide optimal path for service traffics from 200 applications that don't require IP address consistency, when MN moves 201 to a new MA, DMM network could assign new IP address for MN, and then 202 MN could use current MA's IP address for these applications; for the 203 applications that require IP address consistency, when MN moves to a 204 new MA, DMM network should allow MN to use the IP address assigned by 205 previous MA to make sure the address for these applications not 206 change. 208 For the traffic that requires the consistency of IP address, other 209 routing optimization methods such as tunneling and local routing 210 could be implemented. 212 3.3. Local Routing 214 Local routing is another routing optimization method that could be 215 used in the situation that MN and CN are in the same network region. 216 In the same region means MN and CN are under control of the same 217 mobility management entity, e.g. mobility anchor. 219 When MN and CN are in the same region, their traffic path might be 220 shortened significantly by local routing. For example, there is a 221 local routing function in PMIPv6 [2] protocol as shown in Figure 3. 222 When MN and CN are under the control of the same MAG, the local 223 routing path could be set up between MN and CN through the MAG, and 224 then packets will transported along the path of MN--MAG--CN without 225 passing through LMA. 227 +----------+ 228 | LMA | 229 +----------+ 231 +---------+ 232 |------->| MAG |<-----| 233 | +---------+ | 234 | | 235 | | 236 | | 237 | | 238 +--V------+ +----V----+ 239 | MN | | CN | 240 +---------+ +---------+ 242 Figure3: Local Routing in PMIPv6 244 Because in DMM network, MA would be deployed towards to the access 245 network, so when MN and CN are under the same MA, local routing 246 method would provide a optimal path for packets between MN and CN. 248 An example of local routing for DMM network is shown in Figure 4. 250 +---------+ 251 |------->| MA |<-----| 252 | +---------+ | 253 | | 254 | | 255 | | 256 | | 257 +--V------+ +----V----+ 258 | MN | | CN | 259 +---------+ +---------+ 261 Figure4: Local Routing for DMM 263 4. Conclusions 265 This document discusses three kinds of method for routing 266 optimization in DMM network, these methods aims to provide optimal 267 traffic route in DMM network, and they would be suitable for 268 different situations and different traffics. 270 5. Security Considerations 272 Security related issues are not considered in current document. 274 6. IANA Considerations 276 There have been no IANA considerations so far in this document. 278 7. References 280 7.1. Normative References 282 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 283 Levels", BCP 14, RFC 2119, March 1997. 285 [2] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and 286 B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. 288 [3] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in 289 IPv6", RFC 6275, July 2011. 291 7.2. Informative References 293 [4] Chan (Ed.) et al., "Requirements for Distributed Mobility 294 Management", draft-ietf-dmm-requirements-12 (work in progress), 295 Dec 2013. 297 [5] CJ. Bernardos et al,, "PMIPv6-based distributed anchoring", 298 draft-bernardos-dmm-distributed-anchoring-03 (work in progress), 299 Oct 2013. 301 [6] W. Luo, J. Liu,, "PMIP Based DMM Approaches", 302 draft-luo-dmm-pmip-based-dmm-approach-02 (work in progress), 303 July 2013. 305 [7] H. Chan, P. Seite, K. Pentikousis, A. Dutta,, "Distributed 306 Mobility Management Framework", draft-chan-dmm-framework-03 307 (work in progress), Oct 2013. 309 [8] M. Liebsch, P. Seite, G. Karagiannis,, "Distributed Mobility 310 Management - Framework & Analysis", 311 draft-liebsch-dmm-framework-analysis-02 (work in progress), 312 Oct 2013. 314 [9] D. Liu et al,, "Distributed Mobility Management: Current 315 practices and gap analysis", 316 draft-ietf-dmm-best-practices-gap-analysis-02 (work in progress) 317 (work in progress), Oct 2013. 319 Author's Address 321 Xinpeng Wei 322 Huawei Technologies 324 Email: weixinpeng@huawei.com