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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Non-RFC (?) normative reference: ref. 'IPSP' ** Downref: Normative reference to an Informational RFC: RFC 4541 == Outdated reference: A later version (-16) exists of draft-ietf-6man-default-iids-00 -- Obsolete informational reference (is this intentional?): RFC 3633 (Obsoleted by RFC 8415) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6Lo Working Group J. Nieminen 3 Internet-Draft T. Savolainen 4 Intended status: Standards Track M. Isomaki 5 Expires: November 3, 2014 Nokia 6 B. Patil 7 AT&T 8 Z. Shelby 9 Arm 10 C. Gomez 11 Universitat Politecnica de Catalunya/i2CAT 12 May 2, 2014 14 Transmission of IPv6 Packets over BLUETOOTH(R) Low Energy 15 draft-ietf-6lo-btle-01 17 Abstract 19 Bluetooth Smart is the brand name for the low energy feature in the 20 Bluetooth specification defined by the Bluetooth Special Interest 21 Group. The standard Bluetooth radio has been widely implemented and 22 available in mobile phones, notebook computers, audio headsets and 23 many other devices. The low power version of Bluetooth is a 24 specification that enables the use of this air interface with devices 25 such as sensors, smart meters, appliances, etc. The low power 26 variant of Bluetooth is standardized since the revision 4.0 of the 27 Bluetooth specifications, although version 4.1 or newer is required 28 for IPv6. This document describes how IPv6 is transported over 29 Bluetooth Low Energy using 6LoWPAN techniques. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on November 3, 2014. 48 Copyright Notice 50 Copyright (c) 2014 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 1.1. Terminology and Requirements Language . . . . . . . . . . 3 67 2. Bluetooth Low Energy . . . . . . . . . . . . . . . . . . . . 3 68 2.1. Bluetooth Low Energy stack . . . . . . . . . . . . . . . 4 69 2.2. Link layer roles and topology . . . . . . . . . . . . . . 4 70 2.3. Bluetooth LE device addressing . . . . . . . . . . . . . 5 71 2.4. Bluetooth LE packets sizes and MTU . . . . . . . . . . . 5 72 3. Specification of IPv6 over Bluetooth Low Energy . . . . . . . 6 73 3.1. Protocol stack . . . . . . . . . . . . . . . . . . . . . 6 74 3.2. Link model . . . . . . . . . . . . . . . . . . . . . . . 7 75 3.2.1. Stateless address autoconfiguration . . . . . . . . . 8 76 3.2.2. Neighbor discovery . . . . . . . . . . . . . . . . . 8 77 3.2.3. Header compression . . . . . . . . . . . . . . . . . 9 78 3.2.3.1. Remote destination example . . . . . . . . . . . 10 79 3.2.4. Unicast and Multicast address mapping . . . . . . . . 11 80 3.3. Internet connectivity scenarios . . . . . . . . . . . . . 11 81 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 82 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 83 6. Additional contributors . . . . . . . . . . . . . . . . . . . 13 84 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 85 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 86 8.1. Normative References . . . . . . . . . . . . . . . . . . 13 87 8.2. Informative References . . . . . . . . . . . . . . . . . 14 88 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 90 1. Introduction 92 Bluetooth low energy (LE) is a radio technology targeted for devices 93 that operate with coin cell batteries or minimalistic power sources, 94 which means that low power consumption is essential. Bluetooth LE is 95 an especially attractive technology for Internet of Things 96 applications, such as health monitors, environmental sensing, 97 proximity applications and many others. 99 Considering the potential for the exponential growth in the number of 100 sensors and Internet connected devices and things, IPv6 is an ideal 101 protocol due to the large address space it provides. In addition, 102 IPv6 provides tools for stateless address autoconfiguration, which is 103 particularly suitable for sensor network applications and nodes which 104 have very limited processing power or lack a full-fledged operating 105 system. 107 RFC 4944 [RFC4944] specifies the transmission of IPv6 over IEEE 108 802.15.4. The Bluetooth LE link in many respects has similar 109 characteristics to that of IEEE 802.15.4. Many of the mechanisms 110 defined in the RFC 4944 can be applied to the transmission of IPv6 on 111 Bluetooth LE links. This document specifies the details of IPv6 112 transmission over Bluetooth LE links. 114 1.1. Terminology and Requirements Language 116 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 117 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 118 document are to be interpreted as described in RFC 2119 [RFC2119]. 120 The terms 6LN, 6LR and 6LBR are defined as in [RFC6775], with an 121 addition that Bluetooth LE central and Bluetooth LE peripheral can 122 both be either 6LN or 6LBR. 124 2. Bluetooth Low Energy 126 Bluetooth LE is designed for transferring small amounts of data 127 infrequently at modest data rates at a very low cost per bit. 128 Bluetooth Special Interest Group (Bluetooth SIG) has introduced two 129 trademarks, Bluetooth Smart for single-mode devices (a device that 130 only supports Bluetooth LE) and Bluetooth Smart Ready for dual-mode 131 devices. In the rest of the document, the term Bluetooth LE refers 132 to both types of devices. 134 Bluetooth LE was introduced in Bluetooth 4.0 and further enhanced in 135 Bluetooth 4.1 [BTCorev4.1]. Bluetooth SIG will also publish Internet 136 Protocol Support Profile (IPSP) [IPSP], which includes Internet 137 Protocol Support Service (IPSS) and that enables discovery of IP- 138 enabled devices and establishment of link-layer connection for 139 transporting IPv6 packets. IPv6 over Bluetooth LE is dependent on 140 both Bluetooth 4.1 and IPSP. 142 Devices such as mobile phones, notebooks, tablets and other handheld 143 computing devices which will include Bluetooth 4.1 chipsets will also 144 have the low-energy functionality of Bluetooth. Bluetooth LE will 145 also be included in many different types of accessories that 146 collaborate with mobile devices such as phones, tablets and notebook 147 computers. An example of a use case for a Bluetooth LE accessory is 148 a heart rate monitor that sends data via the mobile phone to a server 149 on the Internet. 151 2.1. Bluetooth Low Energy stack 153 The lower layer of the Bluetooth LE stack consists of the Physical 154 (PHY) and the Link Layer (LL). The Physical Layer transmits and 155 receives the actual packets. The Link Layer is responsible for 156 providing medium access, connection establishment, error control and 157 flow control. The upper layer consists of the Logical Link Control 158 and Adaptation Protocol (L2CAP), Attribute Protocol (ATT), Generic 159 Attribute Profile (GATT) and Generic Access Profile (GAP) as shown in 160 Figure 1. The device internal Host Controller Interface (HCI) 161 separates the lower layers, often implemented in the Bluetooth 162 controller, from higher layers, often implemented in the host stack. 163 GATT and Bluetooth LE profiles together enable the creation of 164 applications in a standardized way without using IP. L2CAP provides 165 multiplexing capability by multiplexing the data channels from the 166 above layers. L2CAP also provides fragmentation and reassembly for 167 large data packets. 169 +-------------------------------------------------+ 170 | Applications | 171 +---------------------------------------+---------+ 172 | Generic Attribute Profile | Generic | 173 +--------------------+------------------+ Access | 174 | Attribute Protocol | Security Manager | Profile | 175 +--------------------+------------------+---------+ 176 | Logical Link Control and Adaptation Protocol | 177 - - -+-----------------------+-------------------------+- - - HCI 178 | Link Layer | Direct Test Mode | 179 +-------------------------------------------------+ 180 | Physical Layer | 181 +-------------------------------------------------+ 183 Figure 1: Bluetooth LE Protocol Stack 185 2.2. Link layer roles and topology 187 Bluetooth LE defines two Link Layer roles: the Bluetooth LE central 188 role and the Bluetooth LE peripheral role. A device in the central 189 role, which is called central from now on, has traditionally been 190 able to manage multiple simultaneous connections with a number of 191 devices in the peripheral role, called peripherals from now on. A 192 peripheral is commonly connected to a single central, but since 193 Bluetooth 4.1 can also connect to multiple centrals. In this 194 document for IPv6 networking purposes the Bluetooth LE network (i.e. 195 a Bluetooth LE piconet) follows a star topology shown in the 196 Figure 2, where the router typically implements the Bluetooth LE 197 central role and nodes Bluetooth LE peripheral roles. In the future 198 mesh networking may be defined for IPv6 over Bluetooth LE. 200 Node --. .-- Node 201 \ / 202 Node ---- Router ---- Node 203 / \ 204 Node --' '-- Node 206 Figure 2: Bluetooth LE Star Topology 208 In Bluetooth LE a central is assumed to be less constrained than a 209 peripheral. Hence, in the primary deployment scenario central and 210 peripheral will act as 6LoWPAN Border Router (6LBR) and a 6LoWPAN 211 Node (6LN), respectively. 213 In Bluetooth LE, direct communication only takes place between a 214 central and a peripheral. Hence, in a Bluetooth LE network using 215 IPv6, a radio hop is equivalent to an IPv6 link and vice versa. 217 2.3. Bluetooth LE device addressing 219 Every Bluetooth LE device is identified by a 48-bit device address. 220 The Bluetooth specification describes the device address of a 221 Bluetooth LE device as:"Devices are identified using a device 222 address. Device addresses may be either a public device address or a 223 random device address." [BTCorev4.1]. The public device addresses 224 are based on the IEEE 802-2001 standard [IEEE802-2001]. The random 225 device addresses are generated as defined in the Bluetooth 226 specification. The device addresses are always unique within a 227 Bluetooth LE piconet, but the random addresses are not guaranteed to 228 be globally unique. 230 2.4. Bluetooth LE packets sizes and MTU 232 Optimal MTU defined for L2CAP fixed channels over Bluetooth LE is 27 233 bytes including the L2CAP header of four bytes. Default MTU for 234 Bluetooth LE is hence defined to be 27 bytes. Therefore, excluding 235 L2CAP header of four bytes, protocol data unit (PDU) size of 23 bytes 236 is available for upper layers. In order to be able to transmit IPv6 237 packets of 1280 bytes or larger, link layer fragmentation and 238 reassembly solution is provided by the L2CAP layer. The IPSP defines 239 means for negotiating up a link-layer connection that provides MTU of 240 1280 bytes or higher for the IPv6 layer [IPSP]. 242 3. Specification of IPv6 over Bluetooth Low Energy 244 Before any IP-layer communications can take place over Bluetooth LE, 245 Bluetooth LE enabled nodes such as 6LNs and 6LBRs have to find each 246 other and establish a suitable link-layer connection. The discovery 247 and Bluetooth LE connection setup procedures are documented by 248 Bluetooth SIG in the IPSP specification [IPSP], and hence are out of 249 scope of this document. The IPSP depends on Bluetooth version 4.1, 250 and hence both Bluetooth version 4.1 or newer and IPSP are required 251 for IPv6 communications. 253 Bluetooth LE technology sets strict requirements for low power 254 consumption and thus limits the allowed protocol overhead. 6LoWPAN 255 standards [RFC6775], and [RFC6282] provide useful functionality for 256 reducing overhead which can be applied to Bluetooth LE. This 257 functionality comprises of link-local IPv6 addresses and stateless 258 IPv6 address autoconfiguration (see Section 3.2.1), Neighbor 259 Discovery (see Section 3.2.2) and header compression (see 260 Section 3.2.3). 262 A significant difference between IEEE 802.15.4 and Bluetooth LE is 263 that the former supports both star and mesh topology (and requires a 264 routing protocol), whereas Bluetooth LE does not currently support 265 the formation of multihop networks at the link layer. 267 3.1. Protocol stack 269 Figure 3 illustrates IPv6 over Bluetooth LE stack including the 270 Internet Protocol Support Service. UDP and TCP are provided as 271 examples of transport protocols, but the stack can be used by any 272 other upper layer protocol capable of running atop of IPv6. The 273 6LoWPAN runs on top of Bluetooth LE L2CAP layer. 275 +---------+ +----------------------------+ 276 | IPSS | | UDP/TCP/other | 277 +---------+ +----------------------------+ 278 | GATT | | IPv6 | 279 +---------+ +----------------------------+ 280 | ATT | | 6LoWPAN adapted to LE | 281 +---------+--+----------------------------+ 282 | Bluetooth LE L2CAP | 283 - - +-----------------------------------------+- - - HCI 284 | Bluetooth LE Link Layer | 285 +-----------------------------------------+ 286 | Bluetooth LE Physical | 287 +-----------------------------------------+ 289 Figure 3: IPv6 over Bluetooth LE Stack 291 3.2. Link model 293 The concept of IPv6 link (layer 3) and the physical link (combination 294 of PHY and MAC) needs to be clear and the relationship has to be well 295 understood in order to specify the addressing scheme for transmitting 296 IPv6 packets over the Bluetooth LE link. RFC 4861 [RFC4861] defines 297 a link as "a communication facility or medium over which nodes can 298 communicate at the link layer, i.e., the layer immediately below 299 IPv6." 301 In the case of Bluetooth LE, 6LoWPAN layer is adapted to support 302 transmission of IPv6 packets over Bluetooth LE. The IPSP defines all 303 steps required for setting up the Bluetooth LE connection over which 304 6LoWPAN can function [IPSP], including handling the link-layer 305 fragmentation required on Bluetooth LE, as described in Section 2.4. 307 This specification also assumes the IPv6 header compression format 308 specified in RFC 6282 is used [RFC6282]. It is also assumed that the 309 IPv6 payload length can be inferred from the L2CAP header length and 310 the IID value inferred from the link-layer address with help of 311 Neighbor Cache, if elided from compressed packet. 313 The Bluetooth LE link between two communicating nodes can be 314 considered to be a point-to-point or point-to-multipoint link. When 315 one of the communicating nodes is simultaneously connected to 316 multiple nodes, the link can be viewed as a point-to-multipoint link 317 from the particular node point of view. However, due to Bluetooth LE 318 star topology, each branch of the star is considered to be an 319 individual link and thus only two nodes can directly talk to each 320 other. Node-to-node communications, e.g. using link-local addresses, 321 need to be bridged by the 6LBR. The 6LBR ensures address collisions 322 do not occur (see Section 3.2.2). 324 After the peripheral and central have connected at the Bluetooth LE 325 level, the link can be considered up and IPv6 address configuration 326 and transmission can begin. 328 3.2.1. Stateless address autoconfiguration 330 A Bluetooth LE 6LN performs stateless address autoconfiguration as 331 per RFC 4862 [RFC4862]. A 64-bit Interface identifier (IID) for a 332 Bluetooth LE interface MAY be formed by utilizing the 48-bit 333 Bluetooth device address (see Section 2.3) as defined in RFC 2464 334 "IPv6 over Ethernet" specification [RFC2464]. Alternatively, a 335 randomly generated IID (see Section 3.2.2) can be used instead, for 336 example, as discussed in [I-D.ietf-6man-default-iids]. In the case 337 of randomly generated IID or randomly generated Bluetooth device 338 address, the "Universal/Local" bit MUST be set to 0 [RFC4291]. Only 339 if the Bluetooth device address is known to be a public address the 340 "Universal/Local" bit can be set to 1. 342 As defined in RFC 4291 [RFC4291], the IPv6 link-local address for a 343 Bluetooth LE node is formed by appending the IID, to the prefix 344 FE80::/64, as depicted in Figure 4. 346 10 bits 54 bits 64 bits 347 +----------+-----------------+----------------------+ 348 |1111111010| zeros | Interface Identifier | 349 +----------+-----------------+----------------------+ 351 Figure 4: IPv6 link-local address in Bluetooth LE 353 The tool for a 6LBR to obtain an IPv6 prefix for numbering the 354 Bluetooth LE network is out of scope of this document, but can be, 355 for example, accomplished via DHCPv6 Prefix Delegation [RFC3633] or 356 by using Unique Local IPv6 Unicast Addresses (ULA) [RFC4193]. Due to 357 the link model of the Bluetooth LE (see Section 2.2) the 6LBR MUST 358 set the "on-link" flag (L) to zero in the Prefix Information Option 359 [RFC4861]. This will cause 6LNs to always send packets to the 6LBR, 360 including the case when the destination is another 6LN using the same 361 prefix. 363 3.2.2. Neighbor discovery 365 'Neighbor Discovery Optimization for IPv6 over Low-Power Wireless 366 Personal Area Networks (6LoWPANs)' [RFC6775] describes the neighbor 367 discovery approach as adapted for use in several 6LoWPAN topologies, 368 including the mesh topology. Bluetooth LE does not support mesh 369 networks and hence only those aspects that apply to a star topology 370 are considered. 372 The following aspects of the Neighbor Discovery optimizations 373 [RFC6775] are applicable to Bluetooth LE 6LNs: 375 1. A Bluetooth LE 6LN MUST register its addresses with the 6LBR by 376 sending a Neighbor Solicitation (NS) message with the Address 377 Registration Option (ARO) and process the Neighbor Advertisement (NA) 378 accordingly. The NS with the ARO option SHOULD be sent irrespective 379 of the method used to generate the IID. The 6LN MUST register only 380 one IPv6 address per IPv6 prefix available on a link. 382 2. For sending Router Solicitations and processing Router 383 Advertisements the Bluetooth LE 6LNs MUST, respectively, follow 384 Sections 5.3 and 5.4 of the [RFC6775]. 386 3.2.3. Header compression 388 Header compression as defined in RFC 6282 [RFC6282], which specifies 389 the compression format for IPv6 datagrams on top of IEEE 802.15.4, is 390 REQUIRED in this document as the basis for IPv6 header compression on 391 top of Bluetooth LE. All headers MUST be compressed according to RFC 392 6282 [RFC6282] encoding formats. 394 The Bluetooth LE's star topology structure and ARO can be exploited 395 in order to provide a mechanism for IID compression. The following 396 text describes the principles of IPv6 address compression on top of 397 Bluetooth LE. 399 The ARO option requires use of EUI-64 identifier [RFC6775]. In the 400 case of Bluetooth LE, the field SHALL be filled with the 48-bit 401 device address used by the Bluetooth LE node converted into 64-bit 402 Modified EUI-64 format [RFC4291]. 404 When a 6LN is sending a packet to or through a 6LBR, it MUST fully 405 elide the source address if the source IPv6 address is currently 406 registed with ARO to the 6LBR and the 6LN has registered only one 407 address for the indicated prefix. That is, if SAC=0 and SAM=11 the 408 6LN MUST have registered the source link-local IPv6 address it is 409 using using ARO, and if SAC=1 and SAM=11 the 6LN MUST have registered 410 the source IPv6 address with the prefix related to compression 411 context identified with Context Identifier Extension. The 412 destination IPv6 address MUST be fully elided if the destination 413 address is the same address to which the 6LN has succesfully 414 registered its source IPv6 address with ARO (set DAC=0, DAM=11). The 415 destination IPv6 address MUST be fully or partially elided if the 416 destination address has prefix for which context has been set up, for 417 example, DAC=0 and DAM=01 when destination is link-local, and DAC=1 418 and DAM=01 with Context Identifier Extension if compression context 419 has been configured for the used destination. 421 When a 6LBR is transmitting packets to 6LN, it MUST fully elide the 422 source IID if the source IPv6 address is the one 6LN has used to 423 register its address with ARO (set SAC=0, SAM=11), and it MUST elide 424 the source prefix or address if a compression context related to the 425 IPv6 source address has been set up. The 6LBR also MUST elide the 426 destination IPv6 address if it is currently registered by the 6LN 427 with ARO and thus 6LN can determine it based on indication of link- 428 local prefix (DAC=0) or indication of other prefix (DAC=1 with 429 Context Identifier Extension). 431 3.2.3.1. Remote destination example 433 When a 6LN transmits an IPv6 packet to a remote destination using 434 global Unicast IPv6 addresses, if a context is defined for the prefix 435 of the 6LNs global IPv6 address, the 6LN has to indicate this context 436 in the corresponding source fields of the compressed IPv6 header as 437 per Section 3.1 of RFC 6282 [RFC6282], and has to elide the IPv6 438 source address previously registered with ARO. For this, the 6LN 439 MUST use the following settings in the IPv6 compressed header: CID=1, 440 SAC=1, SAM=11. In this case, the 6LBR can infer the elided IPv6 441 source address since 1) the 6LBR has previously assigned the prefix 442 to the 6LNs; and 2) the 6LBR maintains a Neighbor Cache that relates 443 the Device Address and the IID the device has registered with ARO. 444 If a context is defined for the IPv6 destination address, the 6LN has 445 to also indicate this context in the corresponding destination fields 446 of the compressed IPv6 header, and elide the prefix of the 447 destination IPv6 address. For this, the 6LN MUST set the DAM field 448 of the compressed IPv6 header as DAM=01 (if the context covers a 449 64-bit prefix) or as DAM=11 (if the context covers a full, 128-bit 450 address). CID and DAC MUST be set to CID=1 and DAC=1. Note that 451 when a context is defined for the IPv6 destination address, the 6LBR 452 can infer the elided destination prefix by using the context. 454 When a 6LBR receives an IPv6 packet sent by a remote node outside the 455 Bluetooth LE network, and the destination of the packet is a 6LN, if 456 a context is defined for the prefix of the 6LN's global IPv6 address, 457 the 6LBR has to indicate this context in the corresponding 458 destination fields of the compressed IPv6 header. The 6LBR has to 459 elide the IPv6 destination address of the packet before forwarding 460 it, if the IPv6 destination address is inferable by the 6LN. For 461 this, the 6LBR will set the DAM field of the IPv6 compressed header 462 as DAM=11. CID and DAC needs to be set to CID=1 and DAC=1. If a 463 context is defined for the prefix of the IPv6 source address, the 464 6LBR needs to indicate this context in the source fields of the 465 compressed IPv6 header, and elide that prefix as well. For this, the 466 6LBR needs to set the SAM field of the IPv6 compressed header as 467 SAM=01 (if the context covers a 64-bit prefix) or SAM=11 (if the 468 context covers a full, 128-bit address). CID and SAC are to be set 469 to CID=1 and SAC=1. 471 3.2.4. Unicast and Multicast address mapping 473 The Bluetooth LE link layer does not support multicast. Hence 474 traffic is always unicast between two Bluetooth LE nodes. Even in 475 the case where a 6LBR is attached to multiple 6LNs, the 6LBR cannot 476 do a multicast to all the connected 6LNs. If the 6LBR needs to send 477 a multicast packet to all its 6LNs, it has to replicate the packet 478 and unicast it on each link. However, this may not be energy- 479 efficient and particular care must be taken if the master is battery- 480 powered. In the opposite direction, a 6LN can only transmit data to 481 a single destination (i.e. the 6LBR). Hence, when a 6LN needs to 482 transmit an IPv6 multicast packet, the 6LN will unicast the 483 corresponding Bluetooth LE packet to the 6LBR. The 6LBR will then 484 forward the multicast packet to other 6LNs. To avoid excess unwanted 485 multicast traffic being sent to 6LNs, the 6LBR SHOULD implement MLD 486 Snooping feature [RFC4541]. 488 3.3. Internet connectivity scenarios 490 In a typical scenario, the Bluetooth LE network is connected to the 491 Internet as shown in the Figure 5. 493 6LN 494 \ ____________ 495 \ / \ 496 6LN ---- 6LBR ----- | Internet | 497 / \____________/ 498 / 499 6LN 501 <-- Bluetooth LE --> 503 Figure 5: Bluetooth LE network connected to the Internet 505 In some scenarios, the Bluetooth LE network may transiently or 506 permanently be an isolated network as shown in the Figure 6. 508 6LN 6LN 509 \ / 510 \ / 511 6LN --- 6LBR --- 6LN 512 / \ 513 / \ 514 6LN 6LN 516 <--- Bluetooth LE ---> 518 Figure 6: Isolated Bluetooth LE network 520 It is also possible to have point-to-point connection between two 521 6LNs, one of which being central and another being peripheral. 522 Similarly, it is possible to have point-to-point connections between 523 two 6LBRs, one of which being central and another being peripheral. 525 At this point in time mesh networking with Bluetooth LE is not 526 specified. 528 In the isolated network scenario communications between 6LN and 6LBR 529 can use IPv6 link-local methodology, but for communications between 530 different 6LNs, the 6LBR has to number the network with ULA prefix 531 [RFC4193], and route packets between 6LNs. 533 4. IANA Considerations 535 There are no IANA considerations related to this document. 537 5. Security Considerations 539 The transmission of IPv6 over Bluetooth LE links has similar 540 requirements and concerns for security as for IEEE 802.15.4. 541 Bluetooth LE Link Layer security considerations are covered by the 542 IPSP [IPSP]. 544 Bluetooth LE Link Layer supports encryption and authentication by 545 using the Counter with CBC-MAC (CCM) mechanism [RFC3610] and a 546 128-bit AES block cipher. Upper layer security mechanisms may 547 exploit this functionality when it is available. (Note: CCM does not 548 consume bytes from the maximum per-packet L2CAP data size, since the 549 link layer data unit has a specific field for them when they are 550 used.) 552 Key management in Bluetooth LE is provided by the Security Manager 553 Protocol (SMP), as defined in [BTCorev4.1]. 555 6. Additional contributors 557 Kanji Kerai, Jari Mutikainen, David Canfeng-Chen and Minjun Xi from 558 Nokia have contributed significantly to this document. 560 7. Acknowledgements 562 The Bluetooth, Bluetooth Smart and Bluetooth Smart Ready marks are 563 registred trademarks owned by Bluetooth SIG, Inc. 565 Samita Chakrabarti, Erik Nordmark, and Marcel De Kogel have provided 566 valuable feedback for this draft. 568 Authors would like to give special acknowledgements for Krishna 569 Shingala, Frank Berntsen, and Bluetooth SIG's Internet Working Group 570 for providing significant feedback and improvement proposals for this 571 document. 573 8. References 575 8.1. Normative References 577 [BTCorev4.1] 578 Bluetooth Special Interest Group, "Bluetooth Core 579 Specification Version 4.1", December 2013. 581 [IPSP] Bluetooth Special Interest Group, "Bluetooth Internet 582 Protocol Support Profile Specification - REFERENCE TO BE 583 UPDATED ONCE IPSP IS PUBLISHED", 2014. 585 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 586 Requirement Levels", BCP 14, RFC 2119, March 1997. 588 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 589 Networks", RFC 2464, December 1998. 591 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 592 Architecture", RFC 4291, February 2006. 594 [RFC4541] Christensen, M., Kimball, K., and F. Solensky, 595 "Considerations for Internet Group Management Protocol 596 (IGMP) and Multicast Listener Discovery (MLD) Snooping 597 Switches", RFC 4541, May 2006. 599 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 600 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 601 September 2007. 603 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 604 Address Autoconfiguration", RFC 4862, September 2007. 606 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 607 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 608 September 2011. 610 [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, 611 "Neighbor Discovery Optimization for IPv6 over Low-Power 612 Wireless Personal Area Networks (6LoWPANs)", RFC 6775, 613 November 2012. 615 8.2. Informative References 617 [I-D.ietf-6man-default-iids] 618 Gont, F., Cooper, A., Thaler, D., and W. Will, 619 "Recommendation on Stable IPv6 Interface Identifiers", 620 draft-ietf-6man-default-iids-00 (work in progress), 621 January 2014. 623 [IEEE802-2001] 624 Institute of Electrical and Electronics Engineers (IEEE), 625 "IEEE 802-2001 Standard for Local and Metropolitan Area 626 Networks: Overview and Architecture", 2002. 628 [RFC3610] Whiting, D., Housley, R., and N. Ferguson, "Counter with 629 CBC-MAC (CCM)", RFC 3610, September 2003. 631 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 632 Host Configuration Protocol (DHCP) version 6", RFC 3633, 633 December 2003. 635 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 636 Addresses", RFC 4193, October 2005. 638 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 639 "Transmission of IPv6 Packets over IEEE 802.15.4 640 Networks", RFC 4944, September 2007. 642 Authors' Addresses 644 Johanna Nieminen 645 Nokia 646 Itamerenkatu 11-13 647 Helsinki 00180 648 Finland 650 Email: johannamaria.nieminen@gmail.com 651 Teemu Savolainen 652 Nokia 653 Hermiankatu 12 D 654 Tampere 33720 655 Finland 657 Email: teemu.savolainen@nokia.com 659 Markus Isomaki 660 Nokia 661 Keilalahdentie 2-4 662 Espoo 02150 663 Finland 665 Email: markus.isomaki@nokia.com 667 Basavaraj Patil 668 AT&T 669 1410 E. Renner Road 670 Richardson, TX 75082 671 USA 673 Email: basavaraj.patil@att.com 675 Zach Shelby 676 Arm 677 Hallituskatu 13-17D 678 Oulu 90100 679 Finland 681 Email: zach.shelby@arm.com 683 Carles Gomez 684 Universitat Politecnica de Catalunya/i2CAT 685 C/Esteve Terradas, 7 686 Castelldefels 08860 687 Spain 689 Email: carlesgo@entel.upc.edu