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Checking references for intended status: Experimental ---------------------------------------------------------------------------- No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DHC WG CJ. Bernardos 3 Internet-Draft UC3M 4 Intended status: Experimental A. Mourad 5 Expires: August 2, 2019 InterDigital 6 January 29, 2019 8 SLAP quadrant selection options for DHCPv6 9 draft-bernardos-dhc-slap-quadrant-00 11 Abstract 13 The IEEE originally structured the 48-bit MAC address space in such a 14 way that half of it was reserved for local use. Recently, the IEEE 15 has been working on a new specification (IEEE 802c) which defines a 16 new "optional Structured Local Address Plan" (SLAP) that specifies 17 different assignment approaches in four specified regions of the 18 local MAC address space. 20 The IEEE is working on mechanisms to allocate addresses in the one of 21 these quadrants (IEEE 802.1CQ). There is work also in the IETF 22 working on specifying new mechanism that extends DHCPv6 operation to 23 handle the local MAC address assignments. In this document, we 24 complement this IETF work by defining a mechanism to allow choosing 25 the SLAP quadrant to use in the allocation of the MAC address to the 26 requesting terminal/client. 28 This document proposes extensions to DHCPv6 protocols to enable a 29 DHCPv6 client or a DHCPv6 relay to indicate a preferred SLAP quadrant 30 to the server, so that the server allocates correspondingly the MAC 31 address to the given client or relay. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at https://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on August 2, 2019. 50 Copyright Notice 52 Copyright (c) 2019 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 68 1.1. Problem statement . . . . . . . . . . . . . . . . . . . . 4 69 1.1.1. WiFi terminals . . . . . . . . . . . . . . . . . . . 4 70 1.1.2. Hypervisor: migratable vs non-migratable functions . 5 71 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 72 3. Quadrant selection mechanisms . . . . . . . . . . . . . . . . 6 73 4. DHCPv6 extensions . . . . . . . . . . . . . . . . . . . . . . 8 74 4.1. Address assignment from the preferred SLAP quadrant 75 indicated by the client . . . . . . . . . . . . . . . . . 8 76 4.2. Address assignment from the SLAP quadrant indicated by 77 the relay . . . . . . . . . . . . . . . . . . . . . . . . 10 78 5. DHCPv6 options definitions . . . . . . . . . . . . . . . . . 13 79 5.1. Quad (IA-LL) option . . . . . . . . . . . . . . . . . . . 13 80 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 81 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 82 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 83 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 84 9.1. Normative References . . . . . . . . . . . . . . . . . . 14 85 9.2. Informative References . . . . . . . . . . . . . . . . . 14 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 88 1. Introduction 90 The IEEE originally structured the 48-bit MAC address space in such a 91 way that half of it was reserved for local use (where the U/L bit is 92 set to 1). Recently, the IEEE has been working on a new 93 specification (IEEE 802c [IEEEStd802c-2017]) which defines a new 94 "optional Structured Local Address Plan" (SLAP) that specifies 95 different assignment approaches in four specified regions of the 96 local MAC address space. These four regions, called SLAP quadrants, 97 are briefly described below (see Figure 1 and Figure 2 for details): 99 o Quadrant "Extended Local Identifier" (ELI) MAC addresses are 100 assigned based on a Company ID (CID), which takes 24-bits, leaving 101 the remaining 24-bits for the locally assigned address for each 102 CID for unicast (M-bit = 0) and also for multicast (M-bit = 1). 103 The CID is assigned by the IEEE Registration Authority (RA). 105 o Quadrant "Standard Assigned Identifier" (SAI) MAC addresses are 106 assigned based on a protocol specified in an IEEE 802 standard. 107 For 48-bit MAC addresses, 44 bits are available. Multiple 108 protocols for assigning SAIs may be specified in IEEE standards. 109 Coexistence of multiple protocols may be supported by limiting the 110 subspace available for assignment by each protocol. 112 o Quadrant "Administratively Assigned Identifier" (AAI) MAC 113 addresses are assigned locally by an administrator. Multicast 114 IPv6 packets use a destination address starting in 33-33 and this 115 falls within this space and therefore should not be used to avoid 116 conflict with IPv6 multicast addresses. For 48-bit MAC addresses, 117 44 bits are available. 119 o Quadrant "Reserved for future use" where MAC addresses may be 120 assigned using new methods yet to be defined, or by an 121 administrator like in the AAI quadrant. 123 LSB MSB 124 M X Y Z - - - - 125 | | | | 126 | | | +------------ SLAP Z-bit 127 | | +--------------- SLAP Y-bit 128 | +------------------ X-bit (U/L) = 1 for locally assigned 129 +--------------------- M-bit (I/G) (unicast/group) 131 Figure 1: IEEE 48-bit MAC address structure 133 +----------+-------+-------+-----------------------+----------------+ 134 | Quadrant | Y-bit | Z-bit | Local Identifier Type | Local | 135 | | | | | Identifier | 136 +----------+-------+-------+-----------------------+----------------+ 137 | 01 | 0 | 1 | Extended Local | ELI | 138 | 11 | 1 | 1 | Standard Assigned | SAI | 139 | 00 | 0 | 0 | Administratively | AAI | 140 | | | | Assigned | | 141 | 10 | 1 | 0 | Reserved | Reserved | 142 +----------+-------+-------+-----------------------+----------------+ 144 Figure 2: SLAP quadrants 146 1.1. Problem statement 148 The IEEE is working on mechanisms to allocate addresses in the SAI 149 quadrant (IEEE 802.1CQ project). There is also ongoing work in the 150 IETF [I-D.bvtm-dhc-mac-assign] specifying new mechanism that extends 151 DHCPv6 operation to handle the local MAC address assignments. In 152 this document, we complement ongoing IETF work with mechanisms to 153 allow choosing the SLAP quadrant to use in the allocation of the MAC 154 address to the requesting terminal/client. This document proposes 155 extensions to DHCPv6 protocols to enable a DHCPv6 client or a DHCPv6 156 relay to indicate a preferred SLAP quadrant to the server, so that 157 the server allocates correspondingly the MAC address to the given 158 client or relay. 160 In the following, we describe two application scenarios where a need 161 arises to assign local MAC addresses according to preferred SLAP 162 quadrants. 164 1.1.1. WiFi terminals 166 Today, most of WiFi terminals come with interfaces that have a 167 "burned" MAC address, allocated from the universal address space 168 using a 24-bit Organizationally Unique Identifier (OUI, assigned to 169 IEEE 802 interface vendors). However, recently, the need to assign 170 local (instead of universal) MAC addresses has emerged in particular 171 in the following two scenarios: 173 o IoT (Internet of Things): where there are a lot of cheap, 174 sometimes short lived and disposable devices. Examples of this 175 include: sensors and actuators for health or home automation 176 applications. In this scenario, it is common that upon a first 177 boot, the device uses a temporary MAC address, to send initial 178 DHCP packets to available DHCP servers. IoT devices typically 179 request a single MAC address for each available network interface. 180 Once the server assigns a MAC address, the device abandons its 181 temporary MAC address. This type of device is typically not 182 moving. In general, any type of SLAP quadrant would be good for 183 assigning addresses from, but ELI/SAI quadrants might be more 184 suitable in some scenarios, such as if it is needed that the 185 addresses belong to the CID assigned to the IoT communication 186 device vendor. 188 o Privacy: Today, MAC addresses allow the exposure of users' 189 locations making it relatively easy to track users' movement. One 190 of the mechanisms considered to mitigate this problem is the use 191 of local random MAC addresses, changing them every time the user 192 connects to a different network. In this scenario, devices are 193 typically mobile. Here, AAI is probably the best SLAP quadrant to 194 assign addresses from, as it is the best fit for randomization of 195 addresses, and it is not required for the addresses to survive 196 when changing networks. 198 1.1.2. Hypervisor: migratable vs non-migratable functions 200 In large scale virtualization environments, thousands of virtual 201 machines (VMs) are active. These VMs are typically managed by a 202 hypervisor, in charge of spawning and stopping VMs as needed. The 203 hypervisor is also typically in charge of assigning new MAC addresses 204 to the VMs. If a DHCP solution is in place for that, the hypervisor 205 acts as a DHCP client and requests available DHCP servers to assign 206 one or more MAC addresses (an address block). The hypervisor does 207 not use those addresses for itself, but rather uses them to create 208 new VMs with appropriate MAC addresses. If we assume very large data 209 center environments, such as the ones that are typically used 210 nowadays, it is expected that the data center is divided in different 211 network regions, each one managing its own local address space. In 212 this scenario, there are two possible situations that need to be 213 tackled: 215 o Migratable functions. If a VM (providing a given function) might 216 need to be potentially migrated to another region of the data 217 center (due to maintenance, resilience, end-user mobility, etc.) 218 it is needed that this VM can keep its networking context in the 219 new region, and this includes keeping its MAC addresses. 220 Therefore, this makes better to allocate addresses from the ELI/ 221 SAI SLAP quadrant, which can be centrally allocated by the DHCP 222 server. 224 o Non-migratable functions. If a VM will not be migrated to another 225 region of the data center, then there are no requirements 226 associated to its MAC address, and then it is more efficient to 227 allocate it from the AAI SLAP quadrant, which does not need to be 228 same for all the data centers (i.e., each region can manage its 229 own, without checking for duplicates globally). 231 2. Terminology 233 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 234 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 235 document are to be interpreted as described in [RFC2119]. 237 The DHCPv6 terminology relevant to this specification from the DHCPv6 238 Protocol [RFC8415] applies here. 240 client A device that is interested in obtaining link-layer 241 addresses. It implements the basic DHCPv6 mechanisms 242 needed by a DHCPv6 client as described in [RFC8415] and 243 supports the new options (IA_LL and LLADDR) specified 244 in this document. The client may or may not support 245 address assignment and prefix delegation as specified 246 in [RFC8415]. 248 server Software that manages link-layer address allocation and 249 is able to respond to client queries. It implements 250 basic DHCPv6 server functionality as described in 251 [RFC8415] and supports the new options (IA_LL and 252 LLADDR) specified in this document. The server may or 253 may not support address assignment and prefix 254 delegation as specified in [RFC8415]. 256 address Unless specified otherwise, an address means a link- 257 layer (or MAC) address, as defined in IEEE802. The 258 address is typically 6 bytes long, but some network 259 architectures may use different lengths. 261 address block A number of consecutive link-layer addresses. An 262 address block is expressed as a first address plus a 263 number that designates the number of additional (extra) 264 addresses. A single address can be represented by the 265 address itself and zero extra addresses. 267 3. Quadrant selection mechanisms 269 We next describe some exemplary ways to perform SLAP quadrant 270 selection. These are provided just as informational text to 271 exemplify how the quadrant preference mechanisms could be used. 273 Let's take first an IoT scenario as an example. An IoT terminal 274 might decide on its own the SLAP quadrant it wants to use to obtain a 275 local MAC address, using the following information to take the 276 decision: 278 o Type of IoT deployment: e.g., industrial, domestic, rural, etc. 279 For small deployments, such as domestic ones, the IoT itself can 280 decide to use the AAI quadrant (this might not even involve the 281 use of DHCP, by the terminal just configuring a random address 282 computed by the terminal itself). For large deployments, such as 283 industrial or rural ones, where thousands of terminals might co- 284 exist, the IoT can decide to use the ELI or SAI quadrants. 286 o Mobility: if the IoT terminal can move, then it might prefer to 287 select the SAI or AAI quadrants to minimize address collisions 288 when moving to another network. If the terminal is known to 289 remain fixed, then the ELI is probably the most suitable one to 290 use. 292 o Managed/unmanaged: depending on whether the IoT terminal is 293 managed during its lifetime or cannot be re-configured, the 294 selected quadrant might be different. For example, it can be 295 managed, this means that network topology changes might occur 296 during its lifetime (e.g., due to changes on the deployment, such 297 as extensions involving additional terminals), and this might have 298 an impact on the preferred quadrant (e.g., to avoid potential 299 collisions in the future). 301 o Operation/battery lifetime: depending on the expected lifetime of 302 the terminal a different quadrant might be preferred (as before, 303 to minimize potential address collisions in the future). The 304 previous are examples of parameters that an IoT terminal might use 305 to select a given SLAP quadrant. IoT terminals are typically very 306 resource constrained, so it might be as well that simple decisions 307 are just taken, for example based on pre-configured preferences. 309 If we now take the WiFi terminal scenario, considering for example 310 that a laptop or smartphone connects to a network using its built in 311 MAC address. Due to privacy/security concerns, the terminal might 312 want to configure a local MAC address. The terminal might use 313 different parameters and context information to decide, not only 314 which SLAP quadrant to use for the local MAC address configuration, 315 but also when to perform a change of address (e.g., it might be 316 needed to change address several times). This information includes, 317 but it is not limited to: 319 o Type of network the terminal is connected: public, work, home. 321 o Trusted network? Y/N. 323 o First time visited network? Y/N. 325 o Network geographical location. 327 o Mobility? Y/N. 329 o OS network profile, including security/trust related parameters. 330 Most modern OS keep metadata associated to the networks they can 331 attach to, as for example the level of trust the user or 332 administrator assigns to the network. This information is used to 333 configure how the terminal behaves in terms of advertising itself 334 on the network, firewall settings, etc. But this information can 335 also be used to decide whether to configure a local MAC address or 336 not, from which SLAP quadrant and how often. 338 o Triggers coming from applications regarding location privacy. An 339 app might request to the OS to maximize location privacy (due to 340 the nature of the application) and this might mean the OS to force 341 the use or change of a local MAC address. 343 This information can be used by the terminal to select the SLAP 344 quadrant. For example, if the terminal is moving around (e.g., while 345 connected to a public network in an airport), it is likely that it 346 might change access point several times, and therefore it is best to 347 minimize the chances of address collision, using the SAI or AAI 348 quadrants. If the terminal is not moving and attached to a trusted 349 network (e.g. at work), then it is probably best to select the ELI 350 quadrant. These are just some examples of how to use this 351 information to select the quadrant. 353 Additionally, the information can also be used to trigger subsequent 354 changes of MAC address, to enhance location privacy. Besides, 355 changing the SLAP quadrant used might also be used as an additional 356 enhancement to make harder to track the user location. 358 Last, if we consider the data center scenario, an hypervisor might 359 request local MAC addresses to be assigned to virtual machines. As 360 in the previous scenarios, the hypervisor might select the preferred 361 SLAP quadrant using information provided by the cloud management 362 system (CMS) or virtualization infrastructure manager (VIM) running 363 on top of the hypervisor. This information might include, but is not 364 limited to: 366 o Migratable/non-migratable VM. If the function implemented by the 367 VM is subject to be moved to another physical server or not. This 368 has an impact on the preference for the SLAP quadrant, as some 369 quadrants are better suited (e.g., ELI/SAI) for supporting 370 migration in a large data center. 372 o VM connectivity characteristics , e.g.,: standalone, part of a 373 pool, part of a service graph/chain. If the connectivity 374 characteristics of the VM are known, this can be used by the 375 hypervisor to select the best SLAP quadrant. 377 4. DHCPv6 extensions 379 4.1. Address assignment from the preferred SLAP quadrant indicated by 380 the client 382 We describe next the protocol operations for a client to select a 383 preferred SLAP quadrant using the DHCPv6 signaling procedures 384 described in [I-D.bvtm-dhc-mac-assign]. The signaling flow is shown 385 in Figure 3. 387 +--------+ +--------+ 388 | DHCPv6 | | DHCPv6 | 389 | client | | server | 390 +--------+ +--------+ 391 | | 392 +-------1. Solicit(IA_LL(quad))------->| 393 | | 394 |<--2. Advertise(IA_LL(LLADDR,quad))--+| 395 | | 396 +---3. Request(IA_LL(LLADDR,quad))---->| 397 | | 398 |<------4. Reply(IA_LL(LLADDR))--------+ 399 | | 400 . . 401 . (timer expiring) . 402 . . 403 | | 404 +------5. Renew(IA_LL(LLADDR))-------->| 405 | | 406 |<-----6. Reply(IA_LL(LLADDR))---------+ 407 | | 409 Figure 3: DHCPv6 signaling flow (client-server) 411 1. Link-layer addresses (i.e., MAC addresses) are assigned in 412 blocks. The smallest block is a single address. To request an 413 assignment, the client sends a Solicit message with a IA_LL 414 option in the message. The IA_LL option MUST contain a LLADDR 415 option. In order to indicate the preferred SLAP quadrant, the 416 IA_LL option includes a new quad IA-LL-option, which contains the 417 preferred quadrant. 419 2. The server, upon receiving a IA_LL option, inspects its content 420 and may offer an address or addresses for each LLADDR option 421 according to its policy. The server sends back an Advertise 422 message with an IA_LL option containing an LLADDR option that 423 specifies the addresses being offered. If the server supports 424 the new quad IA-LL-option, and manages a block of addresses 425 belonging to the requested quadrant, the addresses being offered 426 SHOULD belong to the requested quadrant. If the server does not 427 have addresses from the requested quadrant, it MUST return the 428 IA_LL option containing a Status Code option with status set to 429 NoQuadAvail. 431 3. The client waits for available servers to send Advertise 432 responses and picks one server as defined in Section 18.2.9 of 433 [RFC8415]. The client then sends a Request message that includes 434 the IA_LL container option with the LLADDR option copied from the 435 Advertise message sent by the chosen server. It includes the 436 preferred SLAP quadrant in the new quad IA-LL-option. 438 4. Upon reception of a Request message with IA_LL container option, 439 the server assigns requested addresses. The server MAY alter the 440 allocation at this time. It then generates and sends a Reply 441 message back to the client. Upon receiving a Reply message, the 442 client parses the IA_LL container option and may start using all 443 provided addresses. Note that a client that has included a Rapid 444 Commit option in the Solicit, may receive a Reply in response to 445 the Solicit and skip the Advertise and Request steps above 446 (following standard DHCPv6 procedures). 448 5. When the assigned addresses are about to expire, the client sends 449 a Renew message. 451 6. The server responds with a Reply message, including an LLADDR 452 option with extended lifetime. 454 4.2. Address assignment from the SLAP quadrant indicated by the relay 456 We describe next the protocol operations for a relay to select a 457 preferred SLAP quadrant using the DHCPv6 signaling procedures 458 described in [I-D.bvtm-dhc-mac-assign]. This is useful when a DHCPv6 459 server is operating over a large infrastructure split in different 460 network regions, where each region might have different requirements. 461 The signaling flow is shown in Figure 4. 463 +--------+ +--------+ +--------+ 464 | DHCPv6 | | DHCPv6 | | DHCPv6 | 465 | client | | relay | | server | 466 +--------+ +--------+ +--------+ 467 | | | 468 +-----1. Solicit(IA_LL)----->| | 469 | +----2. Relay-forw | 470 | | (Solicit(IA_LL),quad)------>| 471 | | | 472 | |<---3. Relay-reply | 473 | | (Advertise(IA_LL(LLADDR)))--+ 474 |<4. Advertise(IA_LL(LLADDR))+ | 475 |-5. Request(IA_LL(LLADDR))->| | 476 | +-6. Relay-forw | 477 | | (Request(IA_LL(LLADDR)),quad)->| 478 | | | 479 | |<--7. Relay-reply | 480 | | (Reply(IA_LL(LLADDR)))-------+ 481 |<--8. Reply(IA_LL(LLADDR))--+ | 482 | | | 483 . . . 484 . (timer expiring) . 485 . . . 486 | | | 487 +--9. Renew(IA_LL(LLADDR))-->| | 488 | |--10. Relay-forw | 489 | | (Renew(IA_LL(LLADDR)),quad)-->| 490 | | | 491 | |<---11. Relay-reply | 492 | | (Reply(IA_LL(LLADDR)))-----+ 493 |<--12. Reply(IA_LL(LLADDR)--+ | 494 | | | 496 Figure 4: DHCPv6 signaling flow (client-relay-server) 498 1. Link-layer addresses (i.e., MAC addresses) are assigned in 499 blocks. The smallest block is a single address. To request an 500 assignment, the client sends a Solicit message with a IA_LL 501 option in the message. The IA_LL option MUST contain a LLADDR 502 option. 504 2. The DHCP relay receives the Solicit message and encapsulates it 505 in a Relay-forw message. The relay, based on local knowledge 506 and policies, includes in the Relay Agent Remote-ID Option the 507 preferred quadrant. The relay might know which quadrant to 508 request based on local configuration (e.g., the served network 509 contains IoT devices only, thus requiring ELI/SAI) or other 510 means such as based on analyzing the Solicit message from the 511 client. 513 3. The server, upon receiving the forwarded Solicit message 514 including a IA_LL option, inspects its content and decide may 515 offer an address or addresses for each LLADDR option according 516 to its policy. The server sends back an Advertise message with 517 an IA_LL option containing an LLADDR option that specifies the 518 addresses being offered. This message is sent to the Relay in a 519 Relay-reply message. If the server supports the semantics of 520 the preferred quadrant included in the Relay Agent Remote-ID 521 Option, and manages a block of addresses belonging to the 522 requested quadrant, then the addresses being offered SHOULD 523 belong to the requested quadrant. 525 4. The relay sends the received Advertise message to the client. 527 5. The client waits for available servers to send Advertise 528 responses and picks one server as defined in Section 18.2.9 of 529 [RFC8415]. The client then sends a Request message that 530 includes the IA_LL container option with the LLADDR option 531 copied from the Advertise message sent by the chosen server. 533 6. The relay forwards the received Request in a Relay-forw message. 534 It adds in the Relay-forw a quad IA-LL-option with the preferred 535 quadrant. 537 7. Upon reception of the forwarded Request message with IA_LL 538 container option, the server assigns requested addresses. The 539 server MAY alter the allocation at this time. It then generates 540 and sends a Reply message, in a Relay-reply back to the relay. 542 8. Upon receiving a Reply message, the client parses the IA_LL 543 container option and may start using all provided addresses. 545 9. When the assigned addresses are about to expire, the client 546 sends a Renew message. 548 10. This message is forwarded by the Relay in a Relay-forw message, 549 including a quad IA-LL-option with the preferred quadrant. 551 11. The server responds with a Reply message, including an LLADDR 552 option with extended lifetime. This message is sent in a Relay- 553 Reply message. 555 12. The relay sends the Reply message back to the client. 557 5. DHCPv6 options definitions 559 5.1. Quad (IA-LL) option 561 The quad option is used to specify the preferences for the selected 562 quadrants within an IA_LL. The option must be encapsulated in the 563 IA_LL-options field of an IA_LL option. 565 The format of the quad option is: 567 0 1 2 3 568 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 1 569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 570 | OPTION_QUAD | option-len | 571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 572 | quadrant-1 | pref-1 | quadrant-2 | pref-2 | 573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 574 . . 575 . . 576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 578 Figure 5: Quad Option Format 580 option-code OPTION_QUAD (value to be assigned by IANA). 582 option-len 2 * number of included (quadrant, preference). 584 quadrant-n Identifier of the quadrant (0: AAI, 1: ELI: 2, SAI: 585 3, 4: reserved). 587 pref-n Preference associated to quadrant-n. 589 6. IANA Considerations 591 TBD. 593 7. Security Considerations 595 TBD. 597 8. Acknowledgments 599 The authors would like Bernie Volz for his comments on this document. 601 The work in this draft will be further developed and explored under 602 the framework of the H2020 5G-CORAL project (Grant 761586). 604 9. References 606 9.1. Normative References 608 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 609 Requirement Levels", BCP 14, RFC 2119, 610 DOI 10.17487/RFC2119, March 1997, 611 . 613 [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., 614 Richardson, M., Jiang, S., Lemon, T., and T. Winters, 615 "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", 616 RFC 8415, DOI 10.17487/RFC8415, November 2018, 617 . 619 9.2. Informative References 621 [I-D.bvtm-dhc-mac-assign] 622 Volz, B., Mrugalski, T., and C. Bernardos, "Link-Layer 623 Addresses Assignment Mechanism for DHCPv6", draft-bvtm- 624 dhc-mac-assign-02 (work in progress), October 2018. 626 [IEEEStd802c-2017] 627 IEEE Computer Society, "IEEE Standard for Local and 628 Metropolitan Area Networks: Overview and Architecture, 629 Amendment 2: Local Medium Access Control (MAC) Address 630 Usage, IEEE Std 802c-2017". 632 Authors' Addresses 634 Carlos J. Bernardos 635 Universidad Carlos III de Madrid 636 Av. Universidad, 30 637 Leganes, Madrid 28911 638 Spain 640 Phone: +34 91624 6236 641 Email: cjbc@it.uc3m.es 642 URI: http://www.it.uc3m.es/cjbc/ 644 Alain Mourad 645 InterDigital Europe 647 Email: Alain.Mourad@InterDigital.com 648 URI: http://www.InterDigital.com/