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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 PPSP Yunfei. Zhang 2 Internet Draft China Mobile 3 Intended status: Informational March 5, 2009 4 Expires: September 5, 2009 6 Introduction of Distributed Services Network 7 draft-zhang-ppsp-dsn-introduction-00.txt 9 Status of this Memo 11 This Internet-Draft is submitted to IETF in full conformance with the 12 provisions of BCP 78 and BCP 79. 14 Internet-Drafts are working documents of the Internet Engineering 15 Task Force (IETF), its areas, and its working groups. Note that 16 other groups may also distribute working documents as Internet-Drafts. 18 Internet-Drafts are draft documents valid for a maximum of six months 19 and may be updated, replaced, or obsoleted by other documents at any 20 time. It is inappropriate to use Internet-Drafts as reference 21 material or to cite them other than as "work in progress." 23 The list of current Internet-Drafts can be accessed at 24 http://www.ietf.org/ietf/1id-abstracts.txt 26 The list of Internet-Draft Shadow Directories can be accessed at 27 http://www.ietf.org/shadow.html 29 This Internet-Draft will expire on September 5, 2009. 31 Copyright Notice 33 Copyright (c) 2009 IETF Trust and the persons identified as the 34 document authors. All rights reserved. 36 This document is subject to BCP 78 and the IETF Trust's Legal 37 Provisions Relating to IETF Documents in effect on the date of 38 publication of this document(http://trustee.ietf.org/license-info). 39 Please review these documents carefully, as they describe your rights 40 and restrictions with respect to this document. 42 Abstract 44 This draft briefly introduces DSN,a Distributed Service Network 45 proposed by China Mobile in ITU-T as the evolution of NGN.PPSP is a 46 protocol DSN plans to develop to support streaming services in future 47 Internet. 49 Table of Contents 51 1. Introduction................................................2 52 2. Terminology.................................................3 53 2.1. DSN....................................................3 54 2.2. Core node..............................................3 55 2.3. User node..............................................3 56 3. DSN architecture............................................3 57 4. DSN Scenarios[4]............................................5 58 4.1. Service Scenarios......................................5 59 4.1.1. Multimedia telephony services.....................5 60 4.1.2. Streaming services................................6 61 4.1.3. Content distribution service......................6 62 4.1.4. Large-scale High Bandwidth Multi-media Service....7 63 4.2. Carrier Deployment Scenarios...........................7 64 4.2.1. Carrier private network-based Deployment..........7 65 4.2.2. Internet Deployment...............................7 66 5. Relationship between DSN and PPSP...........................8 67 6. Security Considerations.....................................8 68 7. References..................................................9 69 7.1. Normative References...................................9 70 7.2. Informative References.................................9 72 1. Introduction 74 DSN[1],the abbreviation of Distributed Services Network, is a new 75 question being standardized in ITU-T proposed by China Mobile. The 76 first DSN conference was held on January 11th to 23rd,2009 in ITU-T 77 SG13 plenary meeting in Geneva. Two work items, DSN scenarios[2] and 78 requirements[3] of DSN capabilities were approved to set up in 79 current stage. In ITU-T DSN is defined as the evolution of NGN which 80 uses distributed technologies such as P2P to rebuild the core network 81 with lower CAPEX/OPEX and more flexible application support to suit 82 with mobile Internet and FMC development. Therefore it's important to 83 introduce DSN in related STDs like IETF and 3GPP to accelerate 84 NGN/NGI development. PPSP can be used in DSN for p2p streaming 85 applications. 87 2. Terminology 89 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 90 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 91 document are to be interpreted as described in RFC 2119 [RFC2119]. 93 2.1. DSN 95 DSN is the evolution of NGN driven by p2p technology which provides 96 distributed, operatable and managable characteristics to support 97 more carrier's grade rich multimedia services beyond current NGN 98 scope. 100 2.2. Core node 102 Core node refers to the DSN node deployed in service provider domain, 103 e.g. DSL/Wireless access and aggregation network, IP/MPLS core, etc. 105 2.3. User node 107 User node refers to the DSN node in user domain, e.g. PCs, mobile 108 terminals, etc. 110 3. DSN architecture 112 DSN focuses on overlay network layer, which may belong to 113 application-layer in ISO/OSI model. The traditional Internet is a 114 dumbbell structure, which places most of the intelligence in the 115 terminal system and leaves the network as simple as possible. Along 116 with overlay network introduced in the migration of internet, it 117 stresses more intelligence in the middle of the network. To make it 118 clear for designers, we divide this layer into several sub-layers as 119 follows: 121 +-----------------------------------------------------------------+ 122 | Application Sub-Layer | 123 | +-------------------------------------------------------------+ | 124 | | +-----+ +---+ +----------+ +-----------+ +-------+ +------+ | | 125 | | |VoIP | |IM | |Streaming/| |Downloading| |Search | | Game | | | 126 | | | | | | |Mobile TV | | | |Engine | | | | | 127 | | +-----+ +---+ +----------+ +-----------+ +-------+ +------+ | | 128 | +-------------------------------------------------------------+ | 129 |============================ API ================================| 130 | Service EnablerSub-layer | 131 | +-------------------------------------------------------------+ | 132 | | +-----------+ +-----------+ +-----------+ +-----------+ | | 133 | | |Distributed| |Distributed| |Distributed| |Distributed| | | 134 | | |Cache | |Storage | |Relay | |Computing | | | 135 | | +-----------+ +-----------+ +-----------+ +-----------+ | | 136 | +-------------------------------------------------------------+ | 137 | Enhanced P2P Control Sub-layer | 138 | +-------------------------------------------------------------+ | 139 | |+----------+ +------+ +---------+ +------------+ +----------+| | 140 | || P2P | | P2P | | P2P | |Overlay | | Platform || | 141 | || Mobility | | QoS | | Security| |Interworking| |&User mgmt|| | 142 | |+----------+ +------+ +---------+ +------------+ +----------+| | 143 | +-------------------------------------------------------------+ | 144 | Basic P2P Routing Sub-layer | 145 | +-------------------------------------------------------------+ | 146 | | +----------+ +-------------------------+ +-----------+ | | 147 | | |Index | |Distributed Content | |Topo-Aware | | | 148 | | |Mechanism | |Publish/Update/Amendment | |P2P Routing| | | 149 | | +----------+ +-------------------------+ +-----------+ | | 150 | +-------------------------------------------------------------+ | 151 |=================================================================| 152 | +-------------------------------------------------------------+ | 153 | | IP Network | | 154 | +-------------------------------------------------------------+ | 155 +-----------------------------------------------------------------+ 157 Figure 1 DSN Architecture. 159 The bottom in the overlay layer is Pbasic p2p sub-layer where basic 160 p2p functions are involved e.g.,index mechanism, distributed content 161 publish/update/amendment and topology-aware P2P routing. 163 The second is the enhanced p2p control sub-layer where some 164 additional management and control functions for the basic p2p network 165 are developed such as mobility in p2p,QoS mechanism based on p2p 166 technology, different p2p system inter-working and distributed 167 management functions to monitor the p2p system running condition and 168 individual nodes. 170 The third is service enabler sub-layer, which is the basic components 171 to develop applications. They can also be used jointly. For 172 example, VoIP uses distributed relay module and streaming uses 173 distributed cache and storage module where gaming uses both. 175 Atop is application sub-layer where DSN operators open API to expose 176 network capability to both self-run applications and 3rd applications. 178 4. DSN Scenarios[4] 180 DSN applies the P2P technology to provide operators with reduced 181 CAPEX/OPEX, improved scalability/ubiquity, self 182 organization/maintenance and fault tolerance. 184 DSN enables the core architecture of wireless Internet with the 185 combination of P2P technology and other distributed technologies. 186 With DSN, carriers are able to build scalable telecom network 187 platform that deliver multimedia applications and content 188 applications. In DSN application system, the following services are 189 enabled: 191 4.1. Service Scenarios 193 4.1.1. Multimedia telephony services 195 With DSN, carriers can build cost effective and large scale MMTel 196 service system. 198 Compared with existing MMTel system, DSN's service control node is 199 named as core node who collaborate with each other in a peer to peer 200 paradigm. There is no central server for session processing. 202 Core Nodes compose of a P2P overlay which has its own addressing and 203 routing mechanisms. Users are registered in different Core Nodes in 204 the P2P overlay. Core Nodes communicate with each other by exchanging 205 the application routing information. 207 Since there is no central server, a single node failure will not 208 cause system failure. When parts of the nodes are not available in 209 the system, other nodes can continue to provide services as an entire 210 system with the organization of P2P technology without any impact 211 from the unavailable hosts. 213 It is unnecessary to configure the added hosts specifically, instead 214 it only requires that the application layer supports P2P related 215 protocols in the system, and the system will be expanded 216 automatically. All the application layer addressing and routing 217 information are communicated by P2P protocols without manual 218 configuration. And system capacity can be enlarged by adding new Core 219 Nodes even by using user equipment as it can also runs Core Node 220 functions. 222 In a complicated IP environment, end to end QoS is hard to realize 223 because congestion may happen along the media path, "Best of effort" 224 feature may ignores the service requirements of real-time 225 applications such as MMTel. With DSN, a peer acting as a relay node 226 can be inserted to the media path to enhance the performance of real- 227 time service. The relay mechanism can also provides good NAT traverse 228 capability, which allows users to access high quality service after 229 NAT. 231 4.1.2. Streaming services 233 Streaming services become more and more popular in current Internet. 234 Conventional C/S model suffers from performance bottleneck and poor 235 scalability when the number of streaming service subscribers keeps 236 growing. Operators thus would have to maintain the service quality by 237 deploying more and more streaming servers, which increases their 238 CAPEX/OPEX of the network. While in P2P mode, each user acts as a 239 peer that not only downloads the streaming content but uploads the 240 content to other users, thus effectively reduce the burden of 241 streaming server and improve the scalability of streaming service. 243 Streaming across different network domains may cause increased 244 network traffic where a network domain usually means a subnetwork 245 with peers having the vicinity in network topology (e.g. same LAN, 246 same service PoP). Therefore, it is important for DSN to realize 247 traffic localization. 249 4.1.3. Content distribution service 251 DSN enables very large data storage and content delivery with the 252 help of p2p overlay distribution network. In P2P-enabled system, 253 network resources are distributed across peer nodes. Users can 254 provide and obtain resources and data simultaneously. Such features 255 make it easier for very large data storage. For carriers, these 256 features allow maximization of edge network resources and reduce the 257 load of the server. For users, the new technology provides a richer 258 resource and a faster resource-sharing channel. 260 The Content distribution network based on DSN should closely combine 261 with underlying routing and the transmission mechanism to realize the 262 optimization of traffic. 264 4.1.4. Large-scale High Bandwidth Multi-media Service 266 Bandwidth exhausting multimedia service in the future may become the 267 killer application. However it has higher requirements on the network 268 bandwidth and node processing capability. These applications have 269 very high requirements on the carrier network: Presence system 270 requires 3-10M network bandwidth, less than 100ms delay, and 10ms 271 jitter, and also have high requirement on route setup process as well 272 as QoS. DSN intelligent routing mechanism provides routing function 273 for the system, and provides QoS guarantee for large capacity 274 multimedia service on the basis of P2P bandwidth aggregation 275 capability. 277 4.2. Carrier Deployment Scenarios 279 For the real deployment of DSN, it can be classed into private 280 network-based deployment and Internet-based deployment for different 281 applications from the perspective of carriers. 283 4.2.1. Carrier private network-based Deployment 285 Carriers can deploy DSN in the mode of private network. Private 286 network deployment means deploying DSN on the carrier's private 287 network, e.g. IP private network of China Mobile. DSN serving modes 288 are deployed on the private network of carrier, which can NOT be 289 accesses from Internet. They deliver services in a trusted 290 environment, and DSN network will provide the required high security 291 and manageability. This deployment mode, however, only optimizes the 292 serving nodes of its owns compared with the deployment in Internet 293 environment, without maximizing the resources in Internet environment. 294 Private network-based DSN can provide traditional telecom service, 295 including basic voice/video call, supplementary services, value-added 296 service and IM communication, it also provides service interface for 297 future new services (e.g. VoIP service, content delivery, real-time 298 file download and large-capacity multimedia service etc.) with 299 enhanced service capability. Private network-based DSN can interact 300 with traditional telecommunication networks via gateway. 302 4.2.2. Internet Deployment 304 In this mode, DSN node can be deployed over Internet, or services 305 provided by DSN node can be accessed from Internet. DSN node on 306 Internet includes the equipment of carrier and also a large number of 307 user nodes on the Internet. The sufficient resources of Internet can 308 be better utilized, which will drive the carrier to reduce the 309 network deployment cost. In addition, DSN allows the diversity of 310 services. With the service interface provided by carriers, a number 311 of practical service modes will emerge in the open Internet 312 environment. However, a lot of DSN service nodes on the Internet may 313 be the users nodes, whose security and stability can not be 314 guaranteed, and increase the difficulty to control and manage network. 315 Internet-based DSN can help carriers converge Internet service and 316 address the service mode shift from voice to data. Internet-based DSN 317 can also interact with traditional telecommunication networks via 318 gateway. 320 5. Relationship between DSN and PPSP 322 As shown in last section, p2p streaming and other content services 323 are important types in DSN. Therefore we need a uniform p2p streaming 324 protocol run among core nodes and user nodes. It can also be used 325 when there are multiple DSN implementations which can be inter-worked 326 each other for streaming service. 328 6. Security Considerations 330 The motivation of this draft is to introduce Distributed Service 331 Network (DSN). We don't consider security issues in this draft. 333 7. References 335 7.1. Normative References 337 [1] ITU-T DSN, Proposed scope of DSN, 338 http://www.itu.int/md/meetingdoc.asp?lang=en&parent=T09-SG13- 339 090112-C&PageLB=50. 341 [2] ITU-T DSN scenario, Initial draft of supplement Y.dsnscen 342 Supplement on DSN scenarios, http://www.itu.int/md/T09-SG13- 343 090112-TD-WP5/en. 345 [3] ITU-T DSN requirements,Initial draft of recommendation Y.dsnreq 346 "Recommendation on DSN requirements", http://wwwtu.int/md/T09- 347 SG13-090112-TD-WP5/en. 349 [4] DSN whitepaper,unpublished. 351 7.2. Informative References 353 Author's Addresses 355 Yunfei Zhang 356 China Mobile 358 Phone: 86 13601032119 359 Email: zhangyunfei@chinamobile.com