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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'RFC5234' is mentioned on line 568, but not defined Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 ICNRG Hongke Zhang 2 Internet Draft Fei Song 3 Intended status: Informational Wei Quan 4 Expires: October 12, 2019 BJTU 5 Jianfeng Guan 6 Changqiao Xu 7 BUPT 8 April 7, 2019 10 Uniform information with a hybrid naming (hn) scheme 11 draft-zhang-icnrg-hn-10.txt 13 Status of this Memo 15 This Internet-Draft is submitted in full conformance with the 16 provisions of BCP 78 and BCP 79. 18 This document may contain material from IETF Documents or IETF 19 Contributions published or made publicly available before November 20 10, 2008. The person(s) controlling the copyright in some of this 21 material may not have granted the IETF Trust the right to allow 22 modifications of such material outside the IETF Standards Process. 23 Without obtaining an adequate license from the person(s) controlling 24 the copyright in such materials, this document may not be modified 25 outside the IETF Standards Process, and derivative works of it may 26 not be created outside the IETF Standards Process, except to format 27 it for publication as an RFC or to translate it into languages other 28 than English. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF), its areas, and its working groups. Note that 32 other groups may also distribute working documents as Internet- 33 Drafts. 35 Internet-Drafts are draft documents valid for a maximum of six 36 months and may be updated, replaced, or obsoleted by other documents 37 at any time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 The list of current Internet-Drafts can be accessed at 41 http://www.ietf.org/ietf/1id-abstracts.txt 43 The list of Internet-Draft Shadow Directories can be accessed at 44 http://www.ietf.org/shadow.html 45 This Internet-Draft will expire on October 12, 2019. 47 Copyright Notice 49 Copyright (c) 2017 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (http://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with 57 respect to this document. 59 Abstract 61 This document defines a hybrid naming scheme for unifying all kinds 62 of information including resources, services and data. With many 63 proposals of novel network architectures emerging, such as DONA, ICN 64 NDN, the location-based routing starts to transfer to the content 65 based ones. Currently, it is incompatible that many different 66 information naming schemes are adopted in different network 67 proposals, respectively, i.e. flat names in DONA, hierarchical names 68 in NDN. The proposed naming scheme using a hybrid naming structure, 69 including hierarchical components, and the properties of the 70 component assembly plane. The hybrid naming (hn) scheme enables to 71 identify different routing information uniformly, and provides many 72 great advantages, such as high aggregation, limited length, suffix 73 holes remission, fuzzy matching support, high security and good 74 compatibility with IPv4/IPv6, DONA, CCN/NDN and so on. 76 Table of Contents 78 1. Introduction ................................................ 3 79 1.1. Hierarchical naming..................................... 3 80 1.2. Flat naming ............................................ 4 81 1.3. Attribute naming........................................ 4 82 2. Conventions used in this document............................ 4 83 3. Novel hybrid naming (hn) format.............................. 5 84 3.1. Hierarchical component generating .......................6 85 3.2. Flat component generating............................... 6 86 3.3. Attribute component generating ..........................7 87 4. Advantages .................................................. 7 88 4.1. High aggregation........................................ 7 89 4.2. Limited length ......................................... 8 90 4.3. Suffix holes remission.................................. 8 91 4.4. Fuzzy matching support.................................. 9 92 4.5. Good compatibility..................................... 10 93 4.6. High security ......................................... 10 94 5. Transition form IPv4 and IPv6............................... 10 95 5.1. Case one .............................................. 10 96 5.2. Case two .............................................. 11 97 6. Compatibility .............................................. 11 98 6.1. Compatibility with DONA................................ 11 99 6.2. Compatibility with CCN/NDN............................. 12 100 7. Formal Syntax .............................................. 13 101 8. Security Considerations..................................... 13 102 9. IANA Considerations ........................................ 13 103 10. Conclusions ............................................... 13 104 11. References ................................................ 13 105 11.1. Normative References.................................. 13 106 11.2. Informative References................................ 14 107 12. Acknowledgments ........................................... 15 108 Authors' Addresses ............................................ 15 110 1. Introduction 112 1.1. Hierarchical naming 114 A readable naming mechanism based on the hierarchical structure by 115 some emerging network architectures (i.e. Content-Centric Network 116 (CCN) [1]/Named Data Networking (NDN) [2]) has been proposed. This 117 kind of hierarchical name is very similar as identifying a web 118 with a URL for example "/www.bupt.edu.cn/content/a.avi". In this 119 example, "/" is the separator between adjacent components of the 120 name. 122 As we know, many advantages are in this naming scheme.First, 123 it is well compatible with current URL-based applications or 124 systems, which can make it less difficult to deploy novel 125 network. Second, it does a good job of aggregating and can reduce the 126 amount of routing information, thus, to improve the efficiency 127 of routing information search. Besides, the lookup mechanism of this 128 mechanism has a good compatibility with the existing classless inter 129 -domain routing (CIDR) [3]. 131 However, there are also some fatal flaws in hierarchical 132 names. Because it consists of a series of unlimited 133 components. The number of components is variable and the length 134 of each component is not limited. All these features cause the 135 length of names variable and relatively long [4]. In this way, the 136 routing table and forwarding table can be very huge, which results in 137 inefficient search. 139 On the side, when users search for a resource, they might not 140 remember the long name of the resource. For example, users need the 141 resource a.avi, but they might not know the official name 142 "/www.bupt.edu.cn/content/a.avi" or "/www.bupt.edu.cn/movie/a.avi". 143 Thus, hierarchical naming structure is difficult to support a fuzzy 144 matching based on the attributes of names. 146 1.2. Flat naming 148 The flat naming mechanism has been used in other novel network 149 architectures, such as DONA [5] and NetInf [6], of which the name 150 can be produced by cryptographic hashing of the content or its 151 attributes. 153 Since the plane name has no structural restrictions, it can be 154 obtained and used more flexibly. Any string of fixed length, 155 whether readable or not, can be used as a flat name. 157 However, flat names are difficult to aggregate, which increases 158 the number of routing entries and reduces the scalability of the 159 routing table. In addition, it increases the probability for users 160 to forget the official names of the desired information, because 161 most of flat names is not readable. When a user wants to get 162 content, it needs an additional mapping system to connect the 163 user with a readable name and an unreadable name. 165 1.3. Attribute naming 167 The naming mechanism based on attributes of content is used in the 168 CBCB [7]. It enumerates the attribute information of a resource, 169 such as the category, format, date, feature, level and so on. The 170 name is non-unique and is different from the first two mechanisms. 171 Related content can be searched and located through key 172 attributes of the resource. 174 The advantage of this naming scheme is that, it supports search 175 keywords and provides benefits for the fuzzy matching of searching 176 resources. However, for a specific set of resources, there may be 177 many similar attributes. Many attributes are difficult to ensure the 178 uniqueness of naming. Therefore, to ensure uniqueness, the 179 attributes stored in the routing system will be very large. 181 2. Conventions used in this document 183 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 184 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 185 document are to be interpreted as described in RFC 2119 [RFC2119]. 187 In this document, these words will appear with that interpretation 188 only when in ALL CAPS. Lower case uses of these words are not to be 189 interpreted as carrying significance described in RFC 2119. 191 In this document, the characters ">>" preceding an indented line(s) 192 indicates a statement using the key words listed above. This 193 convention aids reviewers in quickly identifying or finding the 194 portions of this RFC covered by these keywords. 196 3. Novel hybrid naming (hn) format 198 By analyzing the above three naming mechanisms in the field of 199 advantages and disadvantages, a hybrid naming method is proposed, 200 emphasizing their advantages and weakening their shortcomings. 202 Most important of all, three different mainstream naming schemes 203 are adopted in different novel network architectures, which makes 204 the networks be hardly compatible and implemented complexly. 206 A simple and comprehensive solution is to integrate them and use 207 them as part of a hybrid naming solution. In other words, each of 208 them requires some novel naming scheme. 210 We proposed a hybrid naming mechanism (named by "hn"), which 211 combines the three naming mechanisms in a sequence, and creates a 212 more powerful and universal naming format. 214 The hybrid naming format should include three components: 216 o Hierarchical component 218 o Flat component 220 o Attribute component 222 Each part carries different information of name in diverse formats, 223 and is combined to an entire name. The hybrid name is started by a 224 symbol "hn://". The order of three parts should be as follows: 226 1. The first part of a name is very essential for the aggregation of 227 routing entries, which adopts a hierarchical structure. The 228 symbol "/" is used to split the hierarchical levels in this part. 230 2. The second part of a name is very important to identify the 231 content uniquely. The second part uses a flat structure and a 232 string with a fix length through hash computing. 234 3. The third part of a name is used to represent the extensive 235 information of resources. The attribute-based structure is 236 selected to use in the third part, which is composed of a series 237 of attribute words. An example of the hybrid name for a movie is 238 shown in Figure 1. 240 +----------------------+---------------+---------------------------+ 241 |hn://www.bjtu.edu.cn/m|u584rnfiur324yh|movie:avi:1024:part1:kongfu| 242 +----------------------+---------------+---------------------------+ 243 Figure 1 An example of hn for a movie 245 An example of the hybrid name for a picture is shown in Figure 2. 247 +--------------------------+---------------+-----------------------+ 248 |hn://www.bjtu.edu.cn/m/pic|fh84rnfiur324ru| jpg:300*500:prairie | 249 +--------------------------+---------------+-----------------------+ 250 Figure 2 An example of hn for a picture 252 3.1. Hierarchical component generating 254 Hierarchical component is the first part of the hn naming format. 255 This part is suppoesed to be generated by a followed reference 256 standard. 258 Strings such as top-level and second-level settings are defined 259 by this standard, which is very useful for greatly facilitating 260 their aggregation. An available but incomplete hierarchical 261 naming component reference standard is the DNS naming scheme. 263 3.2. Flat component generating 265 Flat component is the second part of hn naming scheme. This part is 266 suggested to identify the information using a string with a limited 267 length, and it must be combined with the first part to identify the 268 information uniquely. 270 Flat component can be generated by cryptographic hash algorithm by 271 the information itself or some characters of the information. Even 272 though this part has a low probability of aggregation, it 273 emphasizes and ensures the uniqueness of name. 275 3.3. Attribute component generating 277 Attribute component is set as the third part of hn naming scheme. 278 This part will take it over for the fuzzy matching and some 279 advanced search, i.e. QoS guarantee. This part will also contribute 280 to conduct some potential advanced application based on the useful 281 attributes. It can be generated by extracting the features of the 282 information, such as the format, issue time, file size, catalog, 283 location, popularity, privacy level and so on. 285 4. Advantages 287 4.1. High aggregation 289 The aggregation of naming is very important for the name lookup and 290 storage. According to Google's report, the number of URLs it indexed 291 was 26 million in 1998, which reached to one billion in 2000, and is 292 currently 1 trillion [8]. In July 2011, these URLs could be 293 aggregated to about 280 million domain names, among which 86 million 294 are active. 296 It is a fact that there is a great aggregation for the first few 297 levels of the hierarchical tree. Therefore, the hierarchical 298 structure is placed in the first part of the hn. By this way, the 299 routing entries can be reduced markedly and the aggregation of 300 route can be improved. For example, there are two routing 301 entries"/www.bjtu.edu.cn/m/movie/fhk562nfgjru056:kongfu:avi:1024p:pa 302 rt1 3" and 303 "/www.bjtu.edu.cn/m/picture/fh84rnf213gjrru:jpg:300*500:prairie 3" 304 which have the same forwarding port "3" and prefix 305 "/www.bjtu.edu.cn/m". Therefore, the forwarding port and 306 "/www.bjtu.edu.cn/m" can only be stored in routing table. Above all, 307 it not only reduces the entries of routing table, but also reduces 308 the length of each routing entries. An example of aggregation 309 process is shown in Figure 3. 311 +----------------------------+---------------+------------------+--+ 312 |hn://www.bjtu.edu.cn/m/movie|fhk562nfgjru056|kongfu 1024p part1|3 | 313 +----------------------------+---------------+------------------+--+ 315 +------------------------------+-----------------+---------------+-+ 316 |hn://www.bjtu.edu.cn/m/picture| fh84rnf213gjrru |300*500 prairie|3| 317 +------------------------------+-----------------+---------------+-+ 318 +----------------------+---+ 319 |hn://www.bjtu.edu.cn/m| 3 | 320 +----------------------+---+ 321 Figure 3 An example of aggregation 323 4.2. Limited length 325 The length of name based on hierarchical structure is variable and 326 relatively long, because it is formed by several parts and the 327 number of component is changeable. Kelvin [9] has selected 6627999 328 URL in 78764 different domain names, and the statistics shows that 329 the average length of URL is 76.97 bytes. In ICN, the name must be 330 extracted to query in forwarding table or routing table. And the 331 long name entry will lead to the lower query speed, hence, 332 affecting the performance of routing. 334 The hn naming scheme uses flat naming as part of component in the 335 name to ease this problem. A fix length flat part is embedded behind 336 the hierarchical part. This design not only can prevent the length 337 of names from being not too long, but also will reduce the effect of 338 the aggregation. For example, if the average length of hierarchical 339 part is controlled within 30 bytes, adopting a flat part with a fix 340 length of 20 bytes, then, the whole average length will be 341 restricted within 50 bytes. Compared to 76.97 bytes, the length is 342 shortened by nearly 35%, which will improve the query speed of name 343 greatly using the length dependent algorithms. 345 4.3. Suffix holes remission 347 The suffix hole is a well-known problem for the route of prefix 348 matching. For example, a routing entry "/www.bjtu.edu.cn/movie/3" is 349 stored in the route table for prefix matching. In fact, it is 350 aggregated by "/www.bjtu.edu.cn/movie/a.avi/part1 3"and 351 "/www.bjtu.edu.cn/movie/b.avi/part1 3". In this way, the forwarding 352 packets will be forward from port 3, only if the prefix of name is 353 "/www.bjtu.edu.cn/movie/". However, if packets with a name of 354 "/www.bjtu.edu.cn/movie/c.avi" arrives in the router, it will also 355 be forwarded from port 3. In fact, the network that port 3 connects 356 only has a.avi and b.avi. This causes the so-called suffix holes 357 [10]. 359 In the proposed hn scheme, the problem of suffix holes can be solved 360 by the flat part efficiently. For example, there are two resource 361 names 362 "/www.bjtu.edu.cn/movie/s83hho90oxn2783nde4r:kongfu:avi:1024p:part1 363 3" and 364 "/www.bjtu.edu.cn/movie/8uh723k9ng556sgaesgs:love:rmvb:720p:part2:20 365 12-3-4 3". After route aggregation, the routing entry will become 366 "/www.bjtu.edu.cn/movie/ 3". The routing entry will be matched when 367 a packet whose name is "/www.bjtu.edu.cn/movie/a932jfdjf2032942-jdd: 368 control: avi: 1024p: part1: part2" arrives at this router. 370 However, it could not be forwarded from the port 3 based on hn 371 scheme because of the incomplete prefix matching. There is a suffix 372 list in each aggregating prefix, and the packet will be forwarded 373 only when the requesting suffix exists in the suffix list. In hn 374 scheme, it must assort a suffix list for each routing entries like 375 "/www.bjtu.edu.cn/movie/ 3" to store the flat part of names. 376 Even though the name of the new packet has been matched to the 377 routing entries, its flat part "a932jfdjf2032942-jdd" does not exist 378 in the suffix list "/www.bjtu.edu.cn/movie/ 3". The plat part will be 379 used to decide whether it forwards the request packet when the prefix 380 is matched. By this way, the problem of suffix holes can be resolved 381 effectively. The lookup process of hn names is shown in Figure 4. 383 +----------------------------+-----------------+------------------+ 384 |hn://www.bjtu.edu.cn/main/m/| eld624knhgvfded |kongfu 1024p part1| 385 +----------------------------+-----------------+------------------+ 386 | 387 | Prefix match 388 v 389 +-----------------------+---+ +----------------------+ 390 |/www.bjtu.edu.cn/main/m| 3 |--------------| s83hho90oxn2783nde4r;| 391 | | | | 8uh732k9ng556sgaesgs;| 392 +-----------------------+---+ +----------------------+ 393 | 394 | 395 v 396 +-------+ 397 | seek | 398 +-------+ 399 | | 400 succeed| |failed 401 v v 402 +-------+ +-------+ 403 |forward| |discard| 404 +-------+ +-------+ 405 Figure 4 The hn lookup process 407 4.4. Fuzzy matching support 409 In the practical, it's an essential situation that the users may not 410 know the full official resource name when they search for a resource. 411 The hn naming scheme supports the fuzzy matching according to the 412 function of the attribute component. For example, if the users need 413 the resource a.avi, they don't need to know the official name 414 "hn://www.bjtu.edu.cn/m/|u584uuj89324ru|kongfu:movie:avi:1024p:part1 415 ". In this case, users only publish the information of video 416 "kongfu" and the resolution ratio "1024p". Then the related 417 resources can be found intelligently by fuzzy matching through the 418 attribute component matching, which is the benefit of embedding 419 attribute of resource in the end of name. 421 4.5. Good compatibility 423 This naming scheme provides a good compatibility for all three 424 mainstream naming schemes, which are the subset of the hn naming 425 scheme. 427 4.6. High security 429 It is very similar as identifying a web with a URL in the 430 conventional hierarchical naming mechanism, for example 431 "/www.bjtu.edu.cn/movie/a.avi". However, the name of components is 432 variable. Although it is convenient to get information of every 433 component of the resources, it results in bad security. 435 In the proposed hn scheme, this security problem can be solved. For 436 example, one hn resource name called "/www.bjtu.edu.cn/ 437 s83hho90oxn2783nde4r: kongfu: avi: 1024p: part1 3", and another 438 conventional name "/www.bjtu.edu.cn/movie/a.avi 3". The attacker can 439 know every component when he/she sees the conventional name. On the 440 contrary, the hn name does not have this problem. In the hn naming 441 scheme, people can just know the few components of the resources, 442 thus, the attacker could not attack the components easily. 443 Therefore, this kind of naming scheme has a better security than 444 hierarchical naming mechanism. Also, MD5 algorithm can be applied to 445 the hn naming in order to encrypt the resources displayed in the 446 flat component. 448 5. Transition form IPv4 and IPv6 450 5.1. Case one 452 In a TCP/IP network, IPv4 and IPv6 addresses are used to represent 453 resource locations. IPv4 and IPv6 addresses can also be used to 454 uniquely obtain the required information through the association 455 of port information and content directories. We believe that the 456 hybrid naming scheme shifts from IPv4 and IPv6 networks. 458 The IPv4 or IPv6 address is the hierarchical as the first part of 459 the hybrid name. The port number is placed as the second part of the 460 hybrid name. The third part of hybrid name is the content directory 461 set. An illustration of transition from IPv4 and IPv6 is shown in 462 Figure 5. 464 +--------------------+----+-------------------------------------+--+ 465 |hn://192.168.100.100|8080|m:picture:library:west:computer:book |3 | 466 +--------------------+----+-------------------------------------+--+ 467 +------------------------------------------+----+---------------+--+ 468 |hn://2001.da8.215.a815.c492.d445.3489.ec8c|8080|m:picture:book |3 | 469 +------------------------------------------+----+---------------+--+ 470 Figure 5 Illustration of case one 472 5.2. Case two 474 Another case of transition from URL is shown in Figure 6. For 475 example, the url is 476 "http://www.baidu.com:80/s?wd=icbc&rsv_bp=0&tn=baidu 477 &spt=3&ie=utf8", in which the symbol "?" is followed by a sequence 478 of attributes information. The hn format is shown as following. 480 +------------------+-----+--------------------------------------+--+ 481 |hn://www.baidu.com|80/s?|wd:icbc rsvbp:0 tn:baidu spt:3 ie:utf8|3 | 482 +------------------+-----+--------------------------------------+--+ 483 Figure 6 Illustration of case two 485 6. Compatibility 487 6.1. Compatibility with DONA 489 Data-Oriented Network Architecture (DONA) translates location-based 490 routing into content-based routing. The hybrid naming scheme 491 is well compatible with DONA, and the specific conversion process 492 is as follows. 494 (1)The hierarchical component is transferred into a flat id with a 495 shorter length, which is distinct with the original flat 496 component. 498 (2)This new flat id can be generated by someone similar to a 499 domain name provider. In addition, this flat id can represent 500 a large number of hierarchical names by continuously 501 increasing its length. However, it is usually much shorter 502 than the previous name. 504 (3)According to the variable length of hierarchical components, an 505 integer identifier is designed to identify the length of 506 transferred component. This mechanism is similar to the partition 507 method of subset. 509 (4)The symbol "/" is used for splitting this identifier with flat 510 component. 512 For example, there is a routing entry 513 "/www.bjtu.edu.cn/m/movie/fhk562nfgjru056:kongfu:avi:1024p:part1 3". 514 The first component "www.bjtu.edu.cn/m/movie" is transferred to a 515 unique flat name "dllta", which is settled before the flat 516 component. Meanwhile, we get an identifier "5" to illustrate that 517 the first 5 characters represent the length of transferred 518 hierarchical name. It is significant that the name can be restored 519 easily by their one-to-one mapping. This transformation process 520 is shown in Figure 7. 522 +---------------------------+---------------+-------------------+--+ 523 |hn://www.bjtu.edu.cn/m/movie|fhk562nfgjru056|kongfu 1024p part1|3 | 524 +---------------------------+---------------+-------------------+--+ 525 +---------------------------+--------------------+---+ 526 |dona://dlltafhk562nfgjru056/5|kongfu 1024p part1| 3 | 527 +---------------------------+--------------------+---+ 528 Figure 7 An example of the transformation for hierarchical name 530 6.2. Compatibility with CCN/NDN 532 A readable naming mechanism based on the hierarchical structure has 533 been proposed in CCN/NDN. The hybrid naming scheme is also well 534 compatible with CCN/NDN. The specific transformation process is 535 shown as below. 537 (1)The hierarchical component of hn structure will not be changed as 538 the first unit. 540 (2)The flat component is transferred to one unit followed by the 541 first unit, and uses "/" as separation label. 543 (3)The attributes component is separated as many units, which are 544 separated by the label "/". 546 (4)The transformation between the hybrid naming structure and 547 CCN/NDN hierarchical naming structure can be easily accomplished. 549 For example, there is a routing entry 550 hn://www.bjtu.edu.cn/m/picture|fh84rnf213gjrru|300*500 prairie 3". 551 The components "fh84rnf213gjrru|300*500 prairie" is transferred to 552 several unique units "id=fh84rnf213gjrru/300*500prairie". It is 553 essential that the name can be restored easily according to their 554 one-to-one mapping. This transformation process is shown in Figure 555 8. 557 +------------------------------+-----------------+----------------+-+ 558 |hn://www.bjtu.edu.cn/m/picture| fh84rnf213gjrru |300*500 prairie |3| 559 +------------------------------+-----------------+----------------+-+ 560 +-----------------------------------------------------------------+-+ 561 |ccn://www.bjtu.edu.cn/m/picture/id=fh84rnf213gjrru/300*500prairie|3| 562 +-----------------------------------------------------------------+-+ 563 Figure 8 An example of the transformation for flat name 565 7. Formal Syntax 567 The following syntax specification uses the augmented Backus-Naur 568 Form (BNF) as described in RFC 5234 [RFC5234]. 570 8. Security Considerations 572 The proposed hn naming scheme has potential benefits for the 573 security. The hierarchical prefix has a high aggregation, which can 574 avoid the security issues of rapid expansion in routing or 575 forwarding table, such as DoS attack. The users' privacy and the 576 content secrets can be protected by the flat component from readable 577 names. The attributes component can improve the management for the 578 secure contents by using some encryption key. 580 9. IANA Considerations 582 This document presents no IANA considerations. 584 10. Conclusions 586 This document defines a novel hybrid naming scheme for unifying all 587 kinds of information (including resources, services and data). This 588 hybrid naming scheme owns many advantages, which can provide a 589 better compatibility for existing naming schemes. 591 11. References 593 11.1. Normative References 595 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 596 Requirement Levels", BCP 14, RFC 2119, DOI 597 10.17487/RFC2119, March 1997, . 600 11.2. Informative References 602 [1] Jacobson, V., Smetters, D., Thornton, J., et al. "Networking 603 named content", Proceedings of the 5th international 604 conference on Emerging networking experiments and 605 technologies. ACM 2009 pp. 1-12. 607 [2] Zhang, L., Estrin, D., Jacobson V., et al., "Named Data 608 Networking (NDN) project," Technical Report, NDN-0001, 2010. 610 [3] Yu, J., Varadhan, K., Li, T., et al, "Classless inter-domain 611 routing (CIDR): an address assignment and aggregation 612 strategy", RFC 4632, September 1993. 614 [4] Ding, S., Chen, Z. and Liu, Z., "Parallelizing FIB Lookup in 615 Content Centric Networking", Networking and Distributed 616 Computing (ICNDC), 2012 Third International Conference on. 617 IEEE, 2012 pp. 6-10. 619 [5] Koponen, T., Chawla, M., Chun, B., et al, "A data-oriented 620 (and beyond) network architecture", ACM SIGCOMM Computer 621 Communication Review. ACM, 2007 pp. 181-192. 623 [6] Dannewitz, C., "NetInf: An Information-Centric Design for the 624 Future Internet," Proc. 3rd GI/ITGKuVS Workshop on The Future 625 Internet, Munich, Germany, May 2009. 627 [7] Carzaniga, A., Rutherford, M. and Wolf, A., "A routing scheme 628 for content-based networking", INFOCOM 2004. Twenty-third 629 Annual Joint Conference of the IEEE Computer and 630 Communications Societies. IEEE, 2004 pp. 918-928. 632 [8] https://observatorio.iti.upv.es/resources/new/542 634 [9] http://www.supermind.org/blog/740/average-length-of-a-url- 635 part-2 637 [10] Perino D. and Varvello M., "A reality check for content 638 centric networking", in Proc. ACM SIGCOMM workshop on 639 Information centric networking, 2011 pp. 44-49. 641 12. Acknowledgments 643 Meng Zhang and Liang Zhu contributed to discussion and revision of 644 this document whilst working at Beijing University of Posts and 645 Telecommunications, Beijing, China. 647 This document was prepared using 2-Word-v2.0.template.dot. 649 Authors' Addresses 651 Hongke Zhang 652 Beijing Jiaotong University (BJTU) 653 Beijing, 100044, P.R.China 655 Email: hkzhang@bjtu.edu.cn 657 Fei Song 658 Beijing Jiaotong University (BJTU) 659 Beijing, 100044, P.R.China 661 Email: fsong@bjtu.edu.cn 663 Wei Quan 664 Beijing Jiaotong University (BJTU) 665 Beijing, 100044, P.R.China 667 Email: weiquan@bjtu.edu.cn 669 Jianfeng Guan 670 Beijing University of Posts and Telecommunications (BUPT) 671 Beijing, 100876, P.R.China 673 Email: jfguan@bupt.edu.cn 674 Changqiao Xu 675 Beijing University of Posts and Telecommunications (BUPT) 676 Beijing, 100876, P.R.China 678 Email: cqxu@bupt.edu.cn