idnits 2.17.1 draft-kamei-p2p-experiments-japan-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** You're using the IETF Trust Provisions' Section 6.b License Notice from 12 Sep 2009 rather than the newer Notice from 28 Dec 2009. (See https://trustee.ietf.org/license-info/) Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (November 16, 2009) is 5269 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 P2PRG S. Kamei 3 Internet-Draft NTT Corporation 4 Intended status: Informational T. Momose 5 Expires: May 20, 2010 Cisco Systems 6 T. Inoue 7 T. Nishitani 8 NTT Communications 9 November 16, 2009 11 ALTO-Like Activities and Experiments in P2P Network Experiment Council 12 draft-kamei-p2p-experiments-japan-01 14 Abstract 16 This document provides some suggestions about ALTO architecture 17 through experiments made by P2P Network Experiment Council in Japan. 18 This document also introduces experiments made by the Council in 19 Japan to harmonize P2P technology with the infrastructure. 20 Specifically, this document describes Hint Server technology, which 21 is similar to ALTO technology. 23 Status of this Memo 25 This Internet-Draft is submitted to IETF in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF), its areas, and its working groups. Note that 30 other groups may also distribute working documents as Internet- 31 Drafts. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 The list of current Internet-Drafts can be accessed at 39 http://www.ietf.org/ietf/1id-abstracts.txt. 41 The list of Internet-Draft Shadow Directories can be accessed at 42 http://www.ietf.org/shadow.html. 44 This Internet-Draft will expire on May 20, 2010. 46 Copyright Notice 48 Copyright (c) 2009 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 2. Background in Japan . . . . . . . . . . . . . . . . . . . . . 3 65 2.1. P2P traffic . . . . . . . . . . . . . . . . . . . . . . . 3 66 2.2. Impact on network infrastructure . . . . . . . . . . . . . 4 67 3. The object of P2P Network Experiment Council . . . . . . . . . 5 68 4. Activity in P2P Network Experiment Council . . . . . . . . . . 6 69 4.1. Dummy Node . . . . . . . . . . . . . . . . . . . . . . . . 6 70 4.2. Hint Server ('08) . . . . . . . . . . . . . . . . . . . . 6 71 4.3. Difference between ALTO and Hint Server technology . . . . 9 72 5. High-Level Trial Results . . . . . . . . . . . . . . . . . . . 11 73 5.1. Peer Selection with P2P . . . . . . . . . . . . . . . . . 11 74 5.2. Peer Selection with the Hint Server . . . . . . . . . . . 11 75 6. Next steps . . . . . . . . . . . . . . . . . . . . . . . . . . 12 76 7. Feedback to ALTO WG . . . . . . . . . . . . . . . . . . . . . 12 77 7.1. Harmonizing a Hint Server with ALTO . . . . . . . . . . . 12 78 7.2. Measurement mechanism . . . . . . . . . . . . . . . . . . 13 79 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 80 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 81 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 82 11. Informative References . . . . . . . . . . . . . . . . . . . . 14 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 85 1. Introduction 87 An overlay network, which is used by P2P and other applications, 88 offers the advantage of allowing flexible provision of services while 89 hiding the lower layer network. The downside is that inefficient 90 routes are often taken in the lower IP network, thereby increasing 91 the network load. Several proposals have been made to build an 92 overlay network that takes account of the information about the lower 93 layer network. Since the management of the Internet is highly 94 distributed, it is difficult to implement such proposals and thus 95 optimize a network without the cooperation of network providers. 97 Recently, the controversy between the overlay network and the network 98 providers have been rekindled. Under these circumstances, some 99 researchers have studied overlay network control technology that 100 takes account of the network topology information obtained from 101 network providers. 103 One of activities concerning this issue has been made by the P2P 104 Network Experiment Council in Japan. This document reports on the 105 issues addressed and experiments being made by the P2P Network 106 Experiment Council in Japan, focusing on the experiments made from 107 2007 to 2008. 109 2. Background in Japan 111 2.1. P2P traffic 113 In Japan, the major of P2P applications used today is Winny. P2P 114 applications are the sources of a considerable volume of traffic. 115 Recent study [1] showed more than 60% of Internet traffic in Japan is 116 generated by P2P applications. 118 Although traffic from P2P applications increased much more rapidly 119 than traffic from client-server-type web applications, it has leveled 120 off lately as a result of legal restrictions advocated by copyright 121 management organizations and traffic control implemented by ISPs. 122 According to [2], video delivery sites using Flash has again 123 increased volume of web traffic per user, making P2P traffic 124 relatively less conspicuous than before. 126 Consequently, some believe that P2P traffic is no longer a threat to 127 the infrastructure. P2P applications, however, rapidly became widely 128 used to get around the limit of the servers' capacity, which was 129 caused by the increase in demand for delivery of music files. It is 130 likely that the traffic of client-server video delivery will shift to 131 P2P delivery. 133 In fact, some P2P content delivery systems solve copyright issues, 134 for example, Sharecast, Ocean-Grid, TVBand, and so on. The 135 transmission of President Obama's Inaugural Address, which is the 136 largest-scale transmission of content in recent history, was mostly 137 of the client-server type. However, the delivery by CNN used a P2P 138 plug-in made by Octoshape. Traffic data observed by Illinois 139 University revealed unique traffic patterns that the upstream traffic 140 exceeded the downstream traffic. 142 2.2. Impact on network infrastructure 144 One of advantage of using P2P technology for content delivery is that 145 peers exchange content directly among themselves. This reduces the 146 physical load on servers . Also, P2P applications can reduce 147 upstream traffic from an original content server. This is 148 significant that the charge for upstream traffic is usually traffic- 149 sensitive for content delivery services, and it is not negligible. 151 Actually, the volume of traffic sent by the content server in 152 TVBank's P2P content delivery was reduced by a maximum of 96% 153 compared with the volume of traffic received by users [3]. This 154 indicates the great cost-saving of P2P technology from the 155 perspectives of the load on server hardware and the traffic relaying 156 cost of data centers. However, the story is quite different for 157 network providers. From viewpoint of network providers, the traffic 158 that content servers generate has shifted to the edge network and the 159 amount of traffic has not necessarily been reduced. Another problem 160 for network providers that an extremely inefficient routing may be 161 selected has been raised. It is because overlay network systems are 162 configured without any regard to the structure of the lower layer 163 network or network geometry. 165 Traffic on the Internet used to be limited by the capacity of 166 servers. Today the improvement in the scalability of servers has 167 made it likely that network resources will be used up before server 168 resources are. Using P2P applications increases the volume of 169 traffic per user remarkably. 171 Faced with increase in the load on network infrastructure, network 172 providers are compelled to take actions to overcome the sudden 173 increase in facilities' cost. Representative actions include placing 174 content in IXs or data centers, introducing bandwidth control, and 175 raising the access fees [2]. 177 In the future, video posting sites, which has been delivered using 178 client-server applications, may adopt P2P system. The increase in 179 traffic arising from such a shift will be a great threat to the 180 network. 182 3. The object of P2P Network Experiment Council 184 The Japanese Ministry of Internal Affairs and Communications, which 185 has jurisdiction over information and communication systems in Japan, 186 held meetings of an advisory panel on network neutrality from 2006 to 187 2007 in order to study issues related to next generation networks, 188 such as how to ensure fairness in the use of networks and how to 189 define fairness in cost burden. The panel took an interest in P2P 190 technology as a solution to the impending traffic saturation in the 191 backbone network resulting from the rapid expansion of broadband 192 access in Japan, and formed a "Working Group on the P2P Network", 193 which carried out an intensive study of P2P networks. 195 The Working Group reported that it is necessary to undertake the 196 following four activities, which are intended to encourage the 197 government to adopt relevant policies [4]: 199 o Formulate guidelines to be self-imposed by the industry on P2P 200 file delivery applications, 202 o Promote feasibility tests of P2P networks, 204 o Study the current state of traffic control and promote the sharing 205 of information, 207 o Hold working group meetings on traffic control. 209 The first two proposals led to the establishment of the P2P Network 210 Experiment Council supported by the Japanese Ministry of Internal 211 Affairs and Communications [5]. The Council, with membership from 212 P2P delivery providers, content holders, and network providers, began 213 a variety of delivery experiments, which were expected to strengthen 214 cooperative control between different layers. In contrast to P4P, 215 which takes a relatively top-down approach of adopting architecture 216 based on a proposal from a university, the Council is characterized 217 by its bottom-up approach. The aim of establishing the Council has 218 been described as follows. 220 The rapid growth of broadband access enables content delivery 221 system to deliver high-quality and high-volume videos securely and 222 efficiently. Although P2P technology is an effective technology 223 for this requirement, it still has some issues to be coped with. 224 Therefore, the "P2P Network Experiment Council" was established 225 with the support of the Japanese Ministry of Internal Affairs and 226 Communications with its secretariat set up within the Foundation 227 for MultiMedia Communications (FMMC) in order to formulate 228 guidelines for providers and conduct feasibility tests so that 229 users can receive video delivery services safely. 231 The activities of the P2P Network Experiment Council can be 232 classified into two categories. The first is activities to formulate 233 guidelines for the promotion of the commercial use of P2P technology. 234 These will enable users to use P2P technology safely, and providers 235 to have clear rules they must observe. The other is feasibility 236 tests of P2P technology. The next section mainly reports on 237 experiments conducted from 2007 to 2008. 239 4. Activity in P2P Network Experiment Council 241 4.1. Dummy Node 243 While the effect of delivery using P2P technology on reducing the 244 traffic and the load on servers is well known, traffic behavior in 245 the Internet is not known. However, it is not realistic to measure 246 the behavior of P2P applications at user terminals connected to the 247 Internet because that would require a large-scale arrangement for 248 measurement, such as using Deep Packet Inspection (DPI) on aggregated 249 lines. To solve this problem, dummy nodes have been introduced. 250 Dummy nodes have been settled in the Internet and P2P applications 251 have been installed on these nodes. Dummy nodes enable us to measure 252 and analyze communication among peers. 254 Specifically, Linux servers were installed at 40 sites of some ISPs, 255 and a virtual Windows environment was installed on the servers. P2P 256 applications which were target to measure were running on that 257 environment, and packets were captured by a Linux program to obtain 258 information on communication destinations and communication 259 frequencies. 261 4.2. Hint Server ('08) 263 In Japan, bottleneck in IP networks will shift from access networks 264 to backbone networks and equipments, such as bandwidth between ISPs 265 and capacity in IXs, since FTTH has rapidly spread all over Japan. 266 Under this situation. the Council proposed a less restrictive and 267 more flexible cooperation between ISPs than ALTO. The proposed 268 method consists of the following elements: (1) P2P clients, (2) P2P 269 control servers, and (3) a peer selection hint server, and a Hint 270 Server. (1) and (2) are existing systems but whether (2) exists 271 depends on each application. (3) is a server that provides a hint as 272 to the selection of a peer, and plays a role equivalent to that of 273 iTracker in P4P's study. Note that this proposal was based on 274 results of experiments using dummy nodes. The results showed that it 275 was possible to reduce unnecessary traffic that flows across the 276 boundaries of districts or ISPs through providing information about 277 the physical network to P2P applications. 279 When a peer joins the network, it registers its location information 280 (IP address) and supplementary information (line speed, etc.) with 281 the Hint Server. The Hint Server makes a mapping of the new peer 282 (P2P client) based on network topology information obtained from the 283 ISP, generates a routing table in which peers are listed in the order 284 of priority for selection, and returns the table to the peer. 286 If all information can be made public, the above procedure can 287 produce a result which is close to overall optimization. However, 288 some information held by ISPs can often be confidential. Besides, in 289 some cases, the volume of calculation required to process all 290 information can be excessive. To avoid these problems, it is planned 291 to conduct experiments with a limited set of functions, analyze 292 experiment results, and gradually expand the scope of optimization. 294 A control mechanism that makes use of all possible information is 295 difficult not only technically but also because it is difficult to 296 achieve coordination among providers. In consideration of these 297 difficulties, the P2P Network Experiment Council has been limiting 298 the implementation and experiments to the following scope since 2006. 300 Figure 1 shows an outline of the hint server. 302 +---------+ GetLocation +-------------GeoIP DB Server---------+ 303 | | +-----------+ | +----------+ +-----------+ | 304 | |--|IP Address |-->| | GeoIP DB | |Quagga etc | | 305 | | +-----------+ | +----------+ +-----------+ | 306 | | | +-------------+ +----------------+ | 307 | | +-----------+ | | District | | Routing | | 308 | |--|AS Code: |---| | information | |information(DGP)| | 309 | | |Regional | | | | | | | 310 |P2P Peers| |Information| | | Range of | |AS Code(origin) | | 311 | or | +-----------+ | | IP address | | | | 312 | Contro| | | +-------------+ +----------------+ | 313 | Server | +-------------------------------------+ 314 | | | ^ 315 | | PeerSelection v | 316 | | +-----------+ +--------------------------------------+ 317 | |--|IP Address |-->| +--Prioryty Node Selection System--+ | 318 | | | List | | | | | 319 | | +-----------+ | | Peer candidate ranking | | 320 | | +-----------+ | | | | 321 | |--| Ranking |-->| +----------------------------------+ | 322 | | +-----------+ +--------------------------------------+ 323 +---------+ 325 Figure 1 327 The network information used by the Hint Server is not information 328 solicited from individual ISPs but the AS number and district 329 information, which are more or less already public. Routing tables 330 are not generated. Instead, peers within the same ISP or the same 331 district are selected with higher priority in order to confine 332 traffic to within the same ISP or the same district. 334 When the Hint Server receives an IP address, it returns its attribute 335 information, to achieve the above. A peer can select a peer based on 336 the returned information. This operation is called GetLocation. 337 However, in preparation for the time when it becomes necessary to 338 hide topology information, an interface is provided through which a 339 priority order is returned in response to an input of a list of 340 candidate peers. This operation is called PeerSelection. 342 Although the priority node is selected based on the criterion that it 343 is within the same ISP or the same district, this type of selection 344 is not very effective if the number of participating peers is small. 345 Table 1 shows ratio of peers within the same AS or the same 346 prefecture calculated from the distribution of ASs and prefectures in 347 the IP address space from one-day data on a Winny network. 349 +--------------------+--------+ 350 | Conditions | ratio | 351 +--------------------+--------+ 352 | AS matches | 6.70% | 353 | Prefecture matches | 12.76% | 354 | Both match | 2.09% | 355 | Neither match | 78.45% | 356 +--------------------+--------+ 358 Table 1: AS and prefecture distributions 360 Since, in addition to the above, the presence/absence of content 361 affects the result, the control of selecting a peer within the same 362 district may be inadequate. Therefore, it is necessary to introduce 363 the weight of a continuous quantity that reflects the physical 364 distance or the AS path length as an indicator of the proximity of 365 the areas involved. 367 In consideration of the above, the following two measures are used 368 for the evaluation of proximity between peers in a Hint Server. 370 o AS path length (distance between ISPs) 372 Distances between peers are weighted using the degree of paths' 373 matching from an origin AS to ASs that target peers belong to. 374 The degree of paths' matching means ratio of common paths from an 375 origin AS (for example, 4/6 between A-B-C, and A-B-D, 6/8 between 376 A-B-C-D and A-B-C-E). In this year, the OCN is used as an origin 377 AS. Distance is calculated as int((1.0- degree of matching of AS 378 paths)*15). Distance is 15 if either of AS path is indefinite, 379 and is 0 if there is a perfect match. 381 o Physical distance 383 Distances between peers are measured using physical distance of 384 prefectural capitals that target peers belong to. The distance 385 between prefectural capitals is used to calculate physical 386 distance. Distances between prefectural capitals are sorted into 387 ascending order, and then into bands, with weights 1 to 15 388 assigned to them so that there are a more or less equal number of 389 "capital pairs" in each band. If either of their location is 390 indefinite, distance is equal to 15 and, if they are in the same 391 prefecture, distance is equal to 0. 393 Evaluation of distances between peers showed that the distribution 394 of distances was almost uniform when distances between peers are 395 normalized. This result suggests that using normalized distances 396 expands the area where the control by a Hint Server is effective. 398 4.3. Difference between ALTO and Hint Server technology 400 To explain difference between ALTO and Hint Server technology, 401 architecture proposed by ALTO is described. P4P aims to control 402 traffic in such a way that traffic is confined within the same 403 district or AS. As shown in Figure 2, iTracker provides an interface 404 for P2P content delivery using appTracker and peers in BitTorrent. 405 This arrangement provides a framework for efficient control based on 406 network information. 408 In this framework, it is proposed that ISPs and applications share 409 the following types of information through iTracker: 411 o Info: information about peers within an ISP 413 - ASID AS number 415 - Group number of PID node (peer) 417 - LOC: virtual and geographical coordinates 419 o Policy: information about policy on usage specified by an ISP 420 - Ratio between outgoing traffic and incoming traffic that flows 421 between domains 423 - Desirable daily traffic variation pattern on a link 425 - Specifications about relations between peer groups (PID) 427 o Capability: information about the capability of an ISP 429 - Information about usable service classes 431 - Information about the cache server 433 Note that [6] reports on the results of a field test in which it was 434 attempted to reduce overall traffic by using the above concept to 435 confine traffic exchange destinations to within the same ISP or the 436 same city. It reports that, in an evaluation with a Verizon network, 437 traffic to locations outside an ISP was reduced by 30 to 50% and that 438 the ratio of inter-city traffic to Verizon's total traffic was more 439 or less halved. 441 ISP 442 +------------------------+ Internet 443 | +----------------+ | +------------+ 444 | | iTracker | | | appTracker | 445 | | *Info |--------> +------------+ 446 | | *Policy | | ^ 447 | | *capability | | | 448 | +----------------+ | | 449 | | | 450 | +----------------+ | | 451 | | Peer |----------------+ 452 | +----------------+ | 453 +------------------------+ 455 Figure 2 457 Comparing ALTO with Hint Server technology, the following three 458 differences are observed: 460 o Target of optimization: 462 ALTO technology focuses on optimization within an ISP, while Hint 463 Server technology focuses on optimization in backbone traffic. 465 o Target applications: 467 ALTO technology focuses on supporting BitTorrent, while Hint 468 Server technology does not specify any P2P applications. 470 o Strength of cooperation between P2P providers and ISPs: 472 ALTO technology requires close cooperation between ISPs and P2P 473 providers, while Hint Server technology does not require. 475 5. High-Level Trial Results 477 5.1. Peer Selection with P2P 479 Table 2 shows the result of the analysis of communication in a node 480 of an ISP installed in Tokyo, as an example of measurement results. 482 +-----------------------------------------+------------+------------+ 483 | Conditions | Experiment | Experiment | 484 | | 1 | 2 | 485 +-----------------------------------------+------------+------------+ 486 | *Peers selected within the same ISP | 22% | 29% | 487 | *Peers selected within the same | 19% | 23% | 488 | district | | | 489 | *Peers selected within the same | 5% | 7% | 490 | district and the same ISP | | | 491 +-----------------------------------------+------------+------------+ 493 Table 2: Percentage of communication within the same ISP 495 The table shows that the probability of communication with peers in 496 the same ISP is proportional to the number of population and the 497 share of the ISP in each district. The data show that peers were 498 selected at random. Note that the vendor of a P2P application used 499 in this experiment explained that the mechanism of selection a peer 500 using network information can be implemented. However, peer 501 selection is normally based on past information because users often 502 cannot actually perceive the effect of using network information. 504 5.2. Peer Selection with the Hint Server 506 Since the main objective of this experiment was to verify the 507 operations of the Hint Server and P2P applications, the degree to 508 which traffic in the network was actually reduced was not evaluated. 509 However, the distances between a dummy node and a peer were obtained 510 from data on the dummy nodes. An examination of the distances 511 between a dummy node and a peer revealed that mean value of distance 512 after the Hint Server was introduced was reduced by 10% and that 95% 513 value of that was reduced by 5%. 515 6. Next steps 517 This document has reported on activities aimed at achieving 518 cooperative control between the P2P/overlay network and the network 519 infrastructure. Specifically, it has described issues to be 520 addressed and the activities of the P2P Network Experiment Council in 521 Japan, which was established to address these issues. It has also 522 introduced the Council's activities, from 2007 to 2008, focusing on 523 the use of a Hint Server, which is a feature of the traffic 524 engineering mechanism proposed by the Council. 526 The P2P Network Experiment Council has been renamed the Advanced 527 Network Use Promotion Council. The new Council aims to create new 528 network services suitable for the broadband environment and to 529 promote the widespread use of such services in rural areas. It has 530 expanded its scope of work to include all cache technologies, 531 including P2P technology. It will promote more advanced use of the 532 network by encouraging an exchange of views among a broad spectrum of 533 parties on how to use the network effectively, and by supporting a 534 variety of feasibility tests. 536 The Council aims to continue the analysis of the experiment results 537 obtained, and further study by involving a wider spectrum of P2P 538 providers, network providers and delivery service providers. 540 7. Feedback to ALTO WG 542 This section describes what the authors learned with this experiment 543 would be useful for the ALTO WG. 545 7.1. Harmonizing a Hint Server with ALTO 547 As described before, a Hint Server control mechanism focuses on 548 control between ISPs, while ALTO does control within an ISP. 549 Generally speaking, control mechanism that a peer chooses a replica 550 from its neighbors shows higher performance when probability of a 551 peer having a content is higher. This means ISP cooperation 552 mechanism that enlarges area in choosing peers will have much impact 553 on P2P performance. The authors consider combination of these two 554 mechanisms produce better P2P performance. The authors propose 555 hierarchical structure to harmonize a Hint Server with ALTO. From 556 viewpoint of cooperation between ISPs, fine information is not 557 necessarily required and it is difficult to exchange fine information 558 between ISPs. Considering this situation, the authors use only 559 coarse information to control backbone traffic in the experiments 560 this year, though demand of controlling traffic within an ISP using 561 fine information will arise in the near future. The authors consider 562 that introducing hierarchical structure into ALTO is necessary to 563 cope with both situations. Actually, the authors plan to try a 564 hierarchical control mechanism in the next steps, which include the 565 following two steps. 567 o In the first step, coarse information about whole the network is 568 used to select ISPs. 570 o Next, fine information within the ISP is used to select a peer. 572 7.2. Measurement mechanism 574 In experiments, there were two difficulties as follows: 576 o Evaluating effect of introducing a Hint Server was difficult, 577 since P2P applications had their own measurement mechanisms. 579 o How to treat priority orders of peers suggested by a Hint Server 580 could not be predetermined for P2P applications. 582 From these experiences, the authors consider that clarifying 583 requirements about measurement mechanisms for P2P applications are 584 necessary also in Alto. 586 8. Security Considerations 588 There are no security considerations in this document. 590 9. IANA Considerations 592 No need to describe any request regarding number assignment. 594 10. Acknowledgments 596 These experiments were performed under cooperation among P2P Network 597 Experiment Council members, and DREAMBOAT co.,ltd., Bitmedia Inc., 598 Utagoe. Inc. and Toyama IX have especially supported analyses of the 599 experimernts. The authors appreciate Tohru Asami, Hiroshi Esaki and 600 Tatsuya Yamshita for their constructive comments. 602 11. Informative References 604 [1] Hiroshi Esaki, "The State of Traffic and the Effects of P2P", 605 Special Symposium on Broadband, September 2008 (in Japanese). 607 [2] Yoichi Yamazaki, "ISPs have Begun to Explore Tomorrow due to the 608 Expansion of Traffic", Nikkei Communications, December 2007 (in 609 Japanese). 611 [3] TVBank, "Live Delivery using `BB Broadcast'Achieving 96% Saving 612 in Traffic!", http:.wwww.tv-bank.com/jp/20081031.html, 2008 (in 613 Japanese). 615 [4] Ministry of Internal Affairs and Communications, "Disclosure of 616 the Report `Working Group on P2P Networks'", 617 http://www.soumu.go.jp/menu_news/s-news/2007/070629_11.html, 618 2007 (in Japanese). 620 [5] The Foundation for MultiMedia Communications, "The P2P Network 621 Experiment Council", http://www.fmmc.or.jp/P2P/about.htm, 2007 622 (in Japanese). 624 [6] Open P4P, "P4P Field Tests: Yale-Pando-Verizon", 625 http://www.openp4p.net/front/fieldests, 2009. 627 Authors' Addresses 629 Satoshi Kamei 630 NTT Service Integration Laboratories 631 3-9-11, Midori-cho 632 Musashino-shi, Tokyo 180-8585 633 JP 635 Phone: +81-422-59-6942 636 Email: kamei.satoshi@lab.ntt.co.jp 638 Tsuyoshi Momose 639 Cisco Systems G.K. 640 2-1-1 Nishi-Shinjuku 641 Shinjuku-ku, Tokyo 163-0409 642 JP 644 Phone: +81-3-5324-4154 645 Email: tmomose@cisco.com 646 Takeshi Inoue 647 NTT Communications 648 3-4-1, Shibaura 649 Minato-ku, Tokyo 108-8118 650 JP 652 Phone: +81-3-6733-7177 653 Email: inoue@jp.ntt.net 655 Tomohiro Nishitani 656 NTT Communications 657 1-2-20, Kaigan 658 Minato-ku, Tokyo 105-8535 659 JP 661 Phone: +81-50-3812-4742 662 Email: tomohiro.nishitani@ntt.com