idnits 2.17.1 draft-saldana-tsvwg-simplemux-10.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. 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 (September 3, 2018) is 2062 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'Chabarek' is defined on line 635, but no explicit reference was found in the text ** Downref: Normative reference to an Historic RFC: RFC 1692 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Transport Area Working Group J. Saldana 3 Internet-Draft J. Fernandez Navajas 4 Intended status: Standards Track J. Ruiz Mas 5 Expires: March 7, 2019 University of Zaragoza 6 September 3, 2018 8 Simplemux. A generic multiplexing protocol 9 draft-saldana-tsvwg-simplemux-10 11 Abstract 13 The high amount of small packets present in nowaday's networks 14 results in a low efficiency, as the size of the headers and the 15 payload of these packets can be in the same order of magnitude. In 16 some situations, multiplexing a number of small packets into a bigger 17 one is desirable in order to improve the efficiency. For example, a 18 number of small packets can be sent together between a pair of 19 machines if they share a common network path. This may happen 20 between machines in different locations or even inside a datacenter 21 with a number of servers hosting virtual machines. Thus, the traffic 22 profile can be shifted from small to larger packets, reducing the 23 network overhead and the number of packets per second to be managed 24 by intermediate routers. 26 This document describes Simplemux, a protocol able to encapsulate a 27 number of packets belonging to different protocols into a single 28 packet. Small headers (separators) are added at the beginning of 29 each multiplexed packet, including some flags, the packet length and 30 a "Protocol" field. This allows the inclusion of a number of packets 31 belonging to different protocols (the "multiplexed packets") on a 32 packet of another protocol (the "tunneling protocol"). 34 In order to reduce the overhead, the size of the multiplexing headers 35 is kept very low (it may be a single byte when multiplexing packets 36 of small size). 38 Status of This Memo 40 This Internet-Draft is submitted to IETF in full conformance with the 41 provisions of BCP 78 and BCP 79. 43 Internet-Drafts are working documents of the Internet Engineering 44 Task Force (IETF). Note that other groups may also distribute 45 working documents as Internet-Drafts. The list of current Internet- 46 Drafts is at https://datatracker.ietf.org/drafts/current/. 48 Internet-Drafts are draft documents valid for a maximum of six months 49 and may be updated, replaced, or obsoleted by other documents at any 50 time. It is inappropriate to use Internet-Drafts as reference 51 material or to cite them other than as "work in progress." 53 This Internet-Draft will expire on March 7, 2019. 55 Copyright Notice 57 Copyright (c) 2018 IETF Trust and the persons identified as the 58 document authors. All rights reserved. 60 This document is subject to BCP 78 and the IETF Trust's Legal 61 Provisions Relating to IETF Documents 62 (https://trustee.ietf.org/license-info) in effect on the date of 63 publication of this document. Please review these documents 64 carefully, as they describe your rights and restrictions with respect 65 to this document. 67 Table of Contents 69 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 70 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 71 1.2. Existing multiplexing protocols . . . . . . . . . . . . . 4 72 1.3. Benefits of multiplexing . . . . . . . . . . . . . . . . 5 73 2. Description of the scenario . . . . . . . . . . . . . . . . . 6 74 3. Protocol description . . . . . . . . . . . . . . . . . . . . 6 75 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 76 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 77 6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 78 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 79 7.1. Normative References . . . . . . . . . . . . . . . . . . 14 80 7.2. Informative References . . . . . . . . . . . . . . . . . 14 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 83 1. Introduction 85 The high amount of small packets present in nowaday's networks 86 results in a low efficiency, when the size of the headers and the 87 payload are in the same order of magnitude. In some situations, 88 multiplexing a number of small packets into a bigger one is desirable 89 in order to improve the efficiency. For example, a number of small 90 packets can be sent together between a pair of machines if they share 91 a common network path. This may happen between machines in different 92 locations or even inside a datacenter with a number of servers 93 hosting virtual machines. Thus, the traffic profile can be shifted 94 from small to larger packets, thus reducing the network overhead and 95 the number of packets per second to be managed by intermediate 96 routers. 98 This document describes Simplemux, a protocol able to encapsulate a 99 number of packets belonging to different protocols into a single 100 packet. This can be useful e.g. for grouping small packets and thus 101 reducing the number of packets per second in a network. 103 Simplemux is a generic multiplexing protocol, i.e. it can be used to 104 aggregate a number of packets belonging to a protocol, on a single 105 packet belonging to other (or the same) protocol. 107 In this document we will talk about the "multiplexed" protocol, and 108 the "tunneling" protocol, being Simplemux the "multiplexing" 109 protocol. The "external header" will be the one of the "tunneling" 110 protocol (see the figure (Figure 1)) 112 +--------------------------------+ 113 | Multiplexed Packet | Multiplexed protocol 114 +--------------------------------+ 115 | Simplemux | Multiplexing protocol 116 +--------------------------------+ 117 | Tunneling header | Tunneling protocol 118 +--------------------------------+ 120 Figure 1 122 As an example, if a number of small IPv6 packets have to travel over 123 an IPv4 network, they can be multiplexed and put into a single IPv4 124 packet. In this case, IPv4 is the "tunneling" protocol and IPv6 is 125 the "multiplexed" protocol. The IPv4 header is called in this case 126 the "tunneling" or the "external" header. The simplified scheme of 127 this packet would be: 129 |IPv4 hdr||Simplemux hdr|IPv6 packet||Simplemux hdr|IPv6 packet||...| 131 1.1. Requirements Language 133 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 134 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 135 document are to be interpreted as described in RFC 2119 [RFC2119]. 137 1.2. Existing multiplexing protocols 139 Different multiplexing protocols have been approved by the IETF in 140 the past: 142 o TMux [RFC1692] 144 TMux is able to combine multiple short transport segments, 145 independent of application type, and send them between a server and 146 host pair. As stated in the reference, "The TMux protocol is 147 intended to optimize the transmission of large numbers of small data 148 packets. In particular, communication load is not measured only in 149 bits per seconds but also in packets per seconds, and in many 150 situation the latter is the true performance limit, not the former. 151 The proposed multiplexing is aimed at alleviating this situation." 153 A TMux message appears as: 155 |IP hdr||TMux hdr|Transport segment||TMux hdr|Transport segment||...| 157 Therefore, the Transport Segment is not an entire IP packet, since it 158 does not include the IP header. 160 TMux works "between a server and host pair," so it multiplexes a 161 number of segments between the same pair of machines. However, there 162 are scenarios where a number of low-efficiency flows share a common 163 path, but they do not travel between the same pair of machines. 165 o PPPMux [RFC3153] 167 PPPMux "sends multiple PPP encapsulated packets in a single PPP 168 frame. As a result, the PPP overhead per packet is reduced." Thus, 169 it is able to multiplex complete IP packets, using separators. 171 However, the use of PPPMux requires the use of PPP and L2TP in order 172 to multiplex a number of packets together, as done in TCRTP 173 [RFC4170]. Thus, it introduces more overhead and complexity. 175 An IP packet including a number of them using PPPMux appears as: 177 |IP hdr|L2TP hdr|PPP hdr||PPPMux hdr|packet||PPPMux hdr|packet||...| 179 The scheme proposed by PPPMux is similar to the Compound-Frames of 180 PPP LCP Extensions [RFC1570]. The key differences are that PPPMux is 181 more efficient and that it allows concatenation of variable sized 182 frames. 184 *** 186 The definition of a protocol able to multiplex complete packets, 187 avoiding the need of other protocols as PPP is seen as convenient. 188 The multiplexed packets can be of any kind, since a "Protocol Number" 189 field can be added to each of them. Not all the packets multiplexed 190 together must belong to the same protocol. The general scheme of 191 Simplemux is: 193 |tunnel hdr||Simplemux hdr|packet||Simplemux hdr|packet||...| 195 The Simplemux header includes the "Protocol Number" field, so it 196 permits the multiplexing of different kinds of packets in the same 197 bundle. 199 We will also refer to the Simplemux header with the terms 200 "separator," "Simplemux separator" or "mux separator". In the 201 figures we will also use the abbreviation "Smux". 203 When applied to IP packets, the scheme of a multiplexed packet 204 becomes: 206 |tunnel hdr||Simplemux hdr|IP packet||Simplemux hdr|IP packet||...| 208 1.3. Benefits of multiplexing 210 The benefits of multiplexing are: 212 - Tunneling a number of packets together. If a number of packets 213 have to be tunneled through a network segment, they can be 214 multiplexed and then sent together using a single external header. 215 This will avoid the need for adding a tunneling header to each of the 216 packets, thus reducing the overhead. 218 - Reduction of the amount of packets per second in the network. It 219 is desirable for two main reasons: first, network equipment has a 220 limitation in terms of the number of packets per second it can 221 manage, i.e. many devices are not able to send small packets back to 222 back due to processing delay. 224 - Bandwidth reduction. The presence of high rates of tiny packets 225 translates into an inefficient usage of network resources, so there 226 is a need for mechanisms able to reduce the overhead introduced by 227 low-efficiency flows. When combined with header compression, as done 228 in TCRTP [RFC4170] multiplexing may produce significant bandwidth 229 savings, which are interesting for network operators, since they may 230 alleviate the traffic load in their networks. 232 - Energy savings: a lower amount of packets per second will reduce 233 energy consumption in network equipment since, according to [Bolla], 234 internal packet processing engines and switching fabric require 60% 235 and 18% of the power consumption of high-end routers respectively. 236 Thus, reducing the number of packets to be managed and switched will 237 reduce the overall energy consumption. The measurements deployed in 238 [Chabarek]on commercial routers corroborate this. A study using 239 different packet sizes was presented, and the tests with big packets 240 showed that energy consumption gets reduced, since a non-negligible 241 amount of energy is associated to header processing tasks, and not 242 only to the sending of the packet itself. 244 2. Description of the scenario 246 Simplemux works between a pair of machines. It creates a tunnel 247 between an "ingress" and an "egress". They MAY be the endpoints of 248 the communication, but they MAY also be middleboxes able to multiplex 249 packets belonging to different flows. Different mechanisms MAY be 250 used in order to classify flows according to some criteria (sharing a 251 common path, kind of service, etc.) and to select the flows to be 252 multiplexed and sent to the egress (see Figure 2). 254 +-------+ 255 | | +---------+ +---------+ 256 | | ---> |Simplemux| _ _ |Simplemux| --> 257 |classif| ---> | ingress | ===> ( ` )_ ===> | egress | --> 258 | | +---------+ ( Network `) +---------+ 259 | | --------------------> (_ (_ . _) _) -----------------> 260 +-------+ 261 <--------Simplemux--------> 263 Figure 2 265 3. Protocol description 267 A Simplemux packet consists of: 269 - An external header that is used as the tunneling header for the 270 whole packet. 272 - A series of pairs "Simplemux header" + "packet" of the multiplexed 273 protocol. 275 This is the scheme of a Simplemux packet: 277 |tun hdr||Simplemux hdr|packet||Simplemux hdr|packet||...| 278 The Simplemux header has two different forms: one for the "First 279 Simplemux header," and another one for the rest of the Simplemux 280 headers (called "Non-first Simplemux headers"): 282 o First Simplemux header (after the tunneling header, and before the 283 first multiplexed packet): 285 In order to allow the multiplexing of packets of any length, the 286 number of bytes expressing the length is variable, and a field called 287 "Length Extension" (LXT, one bit) is used to flag if the current byte 288 is the last one including length information. This is the structure 289 of a First Simplemux header: 291 |SPB(1 bit)|LXT(1 bit)|length (6 bits)||LXT(1 bit)|length (7 292 bits)||...||Protocol (8 bits)| 294 - Single Protocol Bit (SPB, one bit) only appears in the first 295 Simplemux header. It is set to 1 if all the multiplexed packets 296 belong to the same protocol (in this case, the "Protocol" field will 297 only appear in the first Simplemux header). It is set to 0 when each 298 packet MAY belong to a different protocol. 300 - Length Extension (LXT, one bit) is 0 if the current byte is the 301 last byte where the length of the first packet is included, and 1 in 302 other case. 304 - Length (LEN, 6, 13, 20, etc. bits): This is the length of the 305 multiplexed packet (in bytes), not including the length field. If 306 the length of the multiplexed packet is less than 64 bytes (less than 307 or equal to 63 bytes), the first LXT is set to 0 and the 6 bits of 308 the length field are the length of the multiplexed packet. If the 309 length of the multiplexed packet is equal or greater than 64 bytes, 310 additional bytes are added. The first bit of each of the added bytes 311 is the LXT. If LXT is set to 1, it means that there is an additional 312 byte for expressing the length. This allows to multiplex packets of 313 any length (see the next figures). 315 - Protocol (8 bits) is the Protocol field of the multiplexed packet, 316 according to IANA "Assigned Internet Protocol Numbers." 318 As an example, a First Simplemux header before a packet smaller than 319 64 (2^6) bytes would be 2 bytes long: 321 0 1 322 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 324 |S|L| | | 325 |P|X| Length | Protocol | 326 |B|T| (6 bits) | (8 bits) | 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 ^ 329 0 331 Figure 3 333 A First Simplemux header before a packet with a length greater or 334 equal to 64 bytes, and smaller than 8192 bytes (2^13) will be 3 bytes 335 long: 337 0 1 2 338 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 339 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 340 |S|L| |L| | | 341 |P|X| Length 1 |X| Length 2 | Protocol | 342 |B|T| (6 bits) |T| (7 bits) | (8 bits) | 343 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 344 ^ ^ 345 1 0 347 Figure 4 349 In this case, the length of the packet will be the number expressed 350 by the concatenation of the bits of Length 1 - Length 2 (total 13 351 bits). Length 1 includes the 6 most significant bits and Length 2 352 the 7 less significant bits. 354 A First Simplemux header before a packet with a length greater of 355 equal to 8192 bytes, and smaller than 1048576 bytes (2^20) would be 4 356 bytes long: 358 0 1 2 3 359 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 360 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 361 |S|L| |L| |L| | | 362 |P|X| Length 1 |X| Length 2 |X| Length 3 | Protocol | 363 |B|T| (6 bits) |T| (7 bits) |T| (7 bits) | (8 bits) | 364 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 365 ^ ^ ^ 366 1 1 0 368 Figure 5 370 In this case, the length of the packet will be the number expressed 371 by the concatenation of the bits of Length 1 - Length 2 - Length 3 372 (total 20 bits). Length 1 includes the 6 most significant bits and 373 Length 3 the less 7 significant bits. 375 More bytes can be added to the length if required, using the same 376 scheme: 1 LXT byte plus 7 bits for expressing the length. 378 o Subsequent (Non-first) Simplemux headers (before the other 379 packets): 381 The Non-first Simplemux headers also employ a format allowing the 382 multiplexing of packets of any length, so the number of bytes 383 expressing the length is variable, and the field Length Extension 384 (LXT, one bit) is used to flag if the current byte is the last one 385 including length information. This is the structure of a Non-first 386 Simplemux header: 388 |LXT(1 bit)|length (7 bits)||LXT(1 bit)|length (7 389 bits)||...||Protocol (8 bits, optional)| 391 - Length Extension (LXT, one bit) is 0 if the current byte is the 392 last byte where the length of the packet is included, and 1 in other 393 case. 395 - Length (LEN, 7, 14, 21, etc. bits): This is the length of the 396 multiplexed packet (in bytes), not including the length field. If 397 the length of the multiplexed packet is less than 128 bytes (less 398 than or equal to 127 bytes), LXT is set to 0 and the 7 bits of the 399 length field represent the length of the multiplexed packet. If the 400 length of the multiplexed packet is greater than 127 bytes, 401 additional bytes are added. The first bit of each of the added bytes 402 is the LXT. If LXT is set to 1, it means that there is an additional 403 byte for expressing the length. This allows to multiplex packets of 404 any length (see the next figures). 406 - Protocol (8 bits) is the Protocol field of the multiplexed packet, 407 according to IANA "Assigned Internet Protocol Numbers". It only 408 appears in Non-first headers if the Single Protocol Bit (SPB) of the 409 First Simplemux header is set to 1. 411 As an example, a Non-first Simplemux header before a packet smaller 412 than 128 bytes, when the protocol bit has been set to 0 in the first 413 header, would be 1 byte long: 415 0 416 0 1 2 3 4 5 6 7 417 +-+-+-+-+-+-+-+-+ 418 |L| | 419 |X| Length | 420 |T| (7 bits) | 421 +-+-+-+-+-+-+-+-+ 422 ^ 423 0 425 SPB = 0 in the first header 427 Figure 6 429 A Non-first Simplemux header before a packet witha a length greater 430 or equal to 128 bytes, and smaller than 16384 (2^14), when the 431 protocol bit has been set to 0 in the first header, will be 2 bytes 432 long: 434 0 1 435 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 436 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 437 |L| |L| | 438 |X| Length 1 |X| Length 2 | 439 |T| (7 bits) |T| (7 bits) | 440 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 441 ^ ^ 442 1 0 444 SPB = 0 in the first header 446 Figure 7 448 A Non-first Simplemux header before a packet with a length greater or 449 equal to 16384 bytes, and smaller than 2097152 bytes (2^21), when the 450 protocol bit has been set to 0 in the first header, will be 3 bytes 451 long: 453 0 1 2 454 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 455 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 456 |L| |L| |L| | 457 |X| Length 1 |X| Length 2 |X| Length 3 | 458 |T| (7 bits) |T| (7 bits) |T| (7 bits) | 459 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 ^ ^ ^ 461 1 1 0 463 SPB = 0 in the first header 465 Figure 8 467 In this case, the length of the packet will be the number expressed 468 by the concatenation of the bits of Length 1 - Length 2 - Length 3 469 (total 21 bits). Length 1 includes the 7 most significant bits and 470 Length 3 the 7 less significant bits. 472 More bytes can be added to the length if required, using the same 473 scheme: 1 LXT byte plus 7 bits for expressing the length. 475 A Non-first Simplemux header before a packet smaller than 128 bytes, 476 when the protocol bit has been set to 1 in the first header, will be 477 2 bytes long: 479 0 1 480 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 481 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 482 |L| | | 483 |X| Length | Protocol | 484 |T| (7 bits) | (8 bits) | 485 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 486 ^ 487 0 489 SPB = 1 in the first header 491 Figure 9 493 A Non-first Simplemux header before a packet with a length greater or 494 equal to 128 bytes, and smaller than 16384 (2^14), when the protocol 495 bit has been set to 1 in the first header, will be 3 bytes long: 497 0 1 2 498 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 499 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 500 |L| |L| | | 501 |X| Length 1 |X| Length 2 | Protocol | 502 |T| (7 bits) |T| (7 bits) | (8 bits) | 503 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 504 ^ ^ 505 1 0 507 SPB = 1 in the first header 509 Figure 10 511 A Non-first Simplemux header before a packet with a length greater of 512 equal to 16384 bytes, and smaller than 2097152 bytes (2^21), when the 513 protocol bit has been set to 1 in the first header, will be 4 bytes 514 long: 516 0 1 2 3 517 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 518 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 519 |L| |L| |L| | | 520 |X| Length 1 |X| Length 2 |X| Length 3 | Protocol | 521 |T| (7 bits) |T| (7 bits) |T| (7 bits) | (8 bits) | 522 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 523 ^ ^ ^ 524 1 1 0 526 SPB = 1 in the first header 528 Figure 11 530 In this case, the length of the packet will be the number expressed 531 by the concatenation of the bits of Length 1 - Length 2 - Length 3 532 (total 21 bits). Length 1 includes the 7 most significant bits and 533 Length 3 the 7 less significant bits. 535 More bytes can be added to the length if required, using the same 536 scheme: 1 LXT byte plus 7 bits for expressing the length. 538 These would be some examples of the whole bundles: 540 Case 1: All the packets belong to the same protocol: The first 541 Simplemux header would be 2 or 3 bytes (for usual packet sizes), and 542 the other Simplemux headers would be 1 or 2 bytes. For small packets 543 (< 128 bytes), the Simplemux header would only require one byte. 545 |tun||1|0|len|Protocol|pkt||0|len|pkt||1|len|0|len|pkt||...| 546 | | | | 547 v v v v 548 (6 bits) (7 bits) (14 bits) 550 |tun||1|1|len|0|len|Protocol|pkt||0|len|pkt||1|len|0|len|pkt||...| 551 | | | | | 552 v v v v v 553 (13 bits) (7 bits) (14 bits) 555 Figure 12 557 Case 2: Each packet may belong to a different protocol: All the 558 Simplemux headers would be 2 or 3 bytes (for usual packet sizes). 560 |tun||0|0|len|Prot|pkt||0|len|Prot|pkt||1|len|0|len|Prot|pkt||...| 561 | | | | 562 v v v v 563 (6 bits) (7 bits) (14 bits) 565 |tun||0|1|len|0|len|Prot|pkt||0|len|Prot|pkt||1|len|0|len|Prot|pkt||...| 566 | | | | | 567 v v v v v 568 (13 bits) (7 bits) (14 bits) 570 Figure 13 572 4. Acknowledgements 574 This work has been partially funded by the EU H2020 Wi-5 project 575 (Grant Agreement no: 644262), the Spanish Ministry of Economy and 576 Competitiveness project TIN2015-64770-R, in cooperation with the 577 European Regional Development Fund (TIN2016-76770-R) and Gobierno de 578 Aragon and FEDER "Construyendo Europa desde Aragon" (Research Group 579 T31_17R). 581 5. IANA Considerations 583 A protocol number for Simplemux should be requested to IANA. 585 As a provisional solution for IP networks, the ingress and the egress 586 optimizers may agree on a UDP port, and use IP/UDP as the 587 multiplexing protocol. 589 6. Security Considerations 591 Simplemux protocol has been developed in such a way that packet 592 aggregation and security can be simultaneously applied to the same 593 traffic flows, i.e. a single security header could protect a number 594 of packets belonging to different flows. 596 As a consequence, the overall efficiency could be improved, as the 597 number of security headers could be reduced from N (being N the 598 number of multiplexed packets) to 1. 600 7. References 602 7.1. Normative References 604 [RFC1570] Simpson, W., Ed., "PPP LCP Extensions", RFC 1570, 605 DOI 10.17487/RFC1570, January 1994, 606 . 608 [RFC1692] Cameron, P., Crocker, D., Cohen, D., and J. Postel, 609 "Transport Multiplexing Protocol (TMux)", RFC 1692, 610 DOI 10.17487/RFC1692, August 1994, 611 . 613 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 614 Requirement Levels", BCP 14, RFC 2119, 615 DOI 10.17487/RFC2119, March 1997, 616 . 618 [RFC3153] Pazhyannur, R., Ali, I., and C. Fox, "PPP Multiplexing", 619 RFC 3153, DOI 10.17487/RFC3153, August 2001, 620 . 622 [RFC4170] Thompson, B., Koren, T., and D. Wing, "Tunneling 623 Multiplexed Compressed RTP (TCRTP)", BCP 110, RFC 4170, 624 DOI 10.17487/RFC4170, November 2005, 625 . 627 7.2. Informative References 629 [Bolla] Bolla, R., Bruschi, R., Davoli, F., and F. Cucchietti, 630 "Energy Efficiency in the Future Internet: A Survey of 631 Existing Approaches and Trends in Energy-Aware Fixed 632 Network Infrastructures", IEEE Communications Surveys and 633 Tutorials vol.13, no.2, pp.223,244, 2011. 635 [Chabarek] 636 Chabarek, J., Sommers, J., Barford, P., Estan, C., Tsiang, 637 D., and S. Wright, "Power Awareness in Network Design and 638 Routing", INFOCOM 2008. The 27th Conference on Computer 639 Communications. IEEE pp.457,465, 2008. 641 Authors' Addresses 643 Jose Saldana 644 University of Zaragoza 645 Dpt. IEC Ada Byron Building 646 Zaragoza 50018 647 Spain 649 Phone: +34 976 762 698 650 Email: jsaldana@unizar.es 652 Julian Fernandez Navajas 653 University of Zaragoza 654 Dpt. IEC Ada Byron Building 655 Zaragoza 50018 656 Spain 658 Phone: +34 976 761 963 659 Email: navajas@unizar.es 661 Jose Ruiz Mas 662 University of Zaragoza 663 Dpt. IEC Ada Byron Building 664 Zaragoza 50018 665 Spain 667 Phone: +34 976 762 158 668 Email: jruiz@unizar.es