idnits 2.17.1 draft-ietf-geopriv-lis-discovery-09.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** The document seems to lack a License Notice according IETF Trust Provisions of 28 Dec 2009, Section 6.b.i or Provisions of 12 Sep 2009 Section 6.b -- however, there's a paragraph with a matching beginning. Boilerplate error? (You're using the IETF Trust Provisions' Section 6.b License Notice from 12 Feb 2009 rather than one of the newer Notices. See https://trustee.ietf.org/license-info/.) Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (April 1, 2009) is 5504 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) ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) == Outdated reference: A later version (-16) exists of draft-ietf-geopriv-http-location-delivery-13 == Outdated reference: A later version (-10) exists of draft-ietf-geopriv-l7-lcp-ps-09 == Outdated reference: A later version (-09) exists of draft-ietf-geopriv-lbyr-requirements-07 Summary: 3 errors (**), 0 flaws (~~), 4 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 GEOPRIV M. Thomson 3 Internet-Draft J. Winterbottom 4 Intended status: Standards Track Andrew 5 Expires: October 3, 2009 April 1, 2009 7 Discovering the Local Location Information Server (LIS) 8 draft-ietf-geopriv-lis-discovery-09 10 Status of This Memo 12 This Internet-Draft is submitted to IETF in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on October 3, 2009. 33 Copyright Notice 35 Copyright (c) 2009 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents in effect on the date of 40 publication of this document (http://trustee.ietf.org/license-info). 41 Please review these documents carefully, as they describe your rights 42 and restrictions with respect to this document. 44 Abstract 46 Discovery of the correct Location Information Server (LIS) in the 47 local access network is necessary for devices that wish to acquire 48 location information from the network. A method is described for the 49 discovery of a LIS. Dynamic Host Configuration Protocol (DHCP) 50 options for IP versions 4 and 6 are defined that specify a URI for a 51 LIS in the local access network. An alternative method that uses 52 URI-enabled NAPTR (U-NAPTR) is described for use where the DHCP 53 option is unsuccessful. 55 Table of Contents 57 1. Introduction and Overview . . . . . . . . . . . . . . . . . . 3 58 1.1. DHCP Discovery . . . . . . . . . . . . . . . . . . . . . . 3 59 1.2. U-NAPTR Discovery . . . . . . . . . . . . . . . . . . . . 3 60 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 61 2. LIS Discovery Using DHCP . . . . . . . . . . . . . . . . . . . 4 62 2.1. DHCPv4 LIS URI Option . . . . . . . . . . . . . . . . . . 4 63 2.2. DHCPv6 LIS URI Option . . . . . . . . . . . . . . . . . . 5 64 3. U-NAPTR for LIS Discovery . . . . . . . . . . . . . . . . . . 6 65 3.1. Determining a Domain Name . . . . . . . . . . . . . . . . 7 66 4. Overall Discovery Procedure . . . . . . . . . . . . . . . . . 7 67 4.1. Residential Gateways . . . . . . . . . . . . . . . . . . . 8 68 4.2. Virtual Private Networks (VPNs) . . . . . . . . . . . . . 9 69 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 70 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 71 6.1. Registration of DHCPv4 and DHCPv6 LIS URI Option Codes . . 10 72 6.2. Registration of a Location Server Application Service 73 Tag . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 74 6.3. Registration of a Location Server Application Protocol 75 Tag for HELD . . . . . . . . . . . . . . . . . . . . . . . 11 76 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 77 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 78 8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 79 8.2. Informative References . . . . . . . . . . . . . . . . . . 13 81 1. Introduction and Overview 83 The location of a device is a useful and sometimes necessary part of 84 many services. A Location Information Server (LIS) is responsible 85 for providing that location information to devices with an access 86 network. The LIS uses knowledge of the access network and its 87 physical topology to generate and serve location information to 88 devices. 90 Each access network requires specific knowledge about topology. 91 Therefore, it is important to discover the LIS that has the specific 92 knowledge necessary to locate a device. That is, the LIS that serves 93 the current access network. Automatic discovery is important where 94 there is any chance of movement outside a single access network. 95 Reliance on static configuration can lead to unexpected errors if a 96 device moves between access networks. 98 This document describes DHCP options and DNS records that a device 99 can use to discover a LIS. 101 The product of a discovery process, such as the one described in this 102 document, is the address of the service. In this document, the 103 result is an http: or https: URI, which identifies a LIS. 105 The URI result from the discovery process is suitable for location 106 configuration only; that is, the device MUST dereference the URI 107 using the process described in HELD 108 [I-D.ietf-geopriv-http-location-delivery]. URIs discovered in this 109 way are not "location URIs" [I-D.ietf-geopriv-lbyr-requirements]; 110 dereferencing one of them provides the location of the requester 111 only. Devices MUST NOT embed these URIs in fields in other protocols 112 designed to carry the location of the device. 114 1.1. DHCP Discovery 116 DHCP ([RFC2131], [RFC3315]) is a commonly used mechanism for 117 providing bootstrap configuration information allowing a device to 118 operate in a specific network environment. The bulk of DHCP 119 information is largely static; consisting of configuration 120 information that does not change over the period that the device is 121 attached to the network. Physical location information might change 122 over this time, however the address of the LIS does not. Thus, DHCP 123 is suitable for configuring a device with the address of a LIS. 125 1.2. U-NAPTR Discovery 127 Where DHCP is not available, the DNS might be able to provide a URI. 128 This document describes a method that uses URI-enabled NAPTR 129 (U-NAPTR) [RFC4848], a Dynamic Delegation Discovery Service (DDDS) 130 profile that supports URI results. 132 For the LIS discovery DDDS application, an Application Service tag 133 "LIS" and an Application Protocol tag "HELD" are created and 134 registered with the IANA. Taking a domain name, this U-NAPTR 135 application uses the two tags to determine the LIS URI. 137 1.3. Terminology 139 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 140 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 141 document are to be interpreted as described in [RFC2119]. 143 This document also uses the term "device" to refer to an end host, or 144 client consistent with its use in HELD. In HELD and RFC3693 145 [RFC3693] parlance, the Device is also the Target. 147 The terms "access network" refers to the network that a device 148 connects to for Internet access. The "access network provider" is 149 the entity that operates the access network. This is consistent with 150 the definition in [I-D.ietf-geopriv-l7-lcp-ps] which combines the 151 Internet Access Provider (IAP) and Internet Service Provider (ISP). 152 The access network provider is responsible for allocating the device 153 a public IP address and for directly or indirectly providing a LIS 154 service. 156 2. LIS Discovery Using DHCP 158 DHCP allows the access network provider to specify the address of a 159 LIS as part of network configuration. If the device is able to 160 acquire a LIS URI using DHCP then this URI is used directly; the 161 U-NAPTR process is not necessary if this option is provided. 163 This document registers a DHCP option for a LIS URI for both IPv4 and 164 IPv6. An "https:" LIS URI that is a product of U-NAPTR MUST be 165 authenticated using the domain name method described in Section 3.1 166 of RFC 2818 [RFC2818]. 168 2.1. DHCPv4 LIS URI Option 170 This section defines a DHCP for IPv4 (DHCPv4) option for the address 171 of a LIS. 173 0 1 2 3 174 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 1 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | LIS_URI | Length | | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 178 . LIS URI . 179 . ... . 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 Figure 1: DHCPv4 LIS URI Option 184 LIS_URI: The IANA assigned option number (TBD). [[IANA/RFC-Editor 185 Note: Please replace TBD with the assigned DHCPv4 option code.]] 187 Length: The length of the entire LIS URI option in octets. 189 LIS URI: The address of the LIS. The URI MUST NOT be terminated by 190 a zero octet. 192 The DHCPv4 version of this URI SHOULD NOT exceed 255 octets in 193 length, but MAY be extended by concatenating multiple option 194 values if necessary, as described in [RFC3396]. 196 2.2. DHCPv6 LIS URI Option 198 This section defines a DHCP for IPv6 (DHCPv6) option for the address 199 of a LIS. The DHCPv6 option for this parameter is similarly 200 formatted to the DHCPv4 option. 202 0 1 2 3 203 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 1 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 205 | OPTION_LIS_URI | Length | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 . LIS URI . 208 . ... . 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 Figure 2: DHCPv6 LIS URI Option 213 OPTION_LIS_URI: The IANA assigned option number (TBD). [[IANA/ 214 RFC-Editor Note: Please replace TBD with the assigned DHCPv6 215 option code.]] 217 Length: The length of the LIS URI option in octets. 219 The semantics and format of the remainder of the LIS URI option 220 are identical to the DHCPv4 option, except for the larger 221 allowance for URI length granted by the 16 bit length field. 222 DHCPv6 prohibits concatenation of option values. 224 3. U-NAPTR for LIS Discovery 226 U-NAPTR resolution for a LIS takes a domain name as input and 227 produces a URI that identifies the LIS. This process also requires 228 an Application Service tag and an Application Protocol tag, which 229 differentiate LIS-related NAPTR records from other records for that 230 domain. 232 Section 6.2 defines an Application Service tag of "LIS", which is 233 used to identify the location service for a particular domain. The 234 Application Protocol tag "HELD", defined in Section 6.3, is used to 235 identify a LIS that understands the HELD protocol 236 [I-D.ietf-geopriv-http-location-delivery]. 238 The NAPTR records in the following example demonstrate the use of the 239 Application Service and Protocol tags. Iterative NAPTR resolution is 240 used to delegate responsibility for the LIS service from 241 "zonea.example.net." and "zoneb.example.net." to 242 "outsource.example.com.". 244 zonea.example.net. 245 ;; order pref flags 246 IN NAPTR 100 10 "" "LIS:HELD" ( ; service 247 "" ; regex 248 outsource.example.com. ; replacement 249 ) 250 zoneb.example.net. 251 ;; order pref flags 252 IN NAPTR 100 10 "" "LIS:HELD" ( ; service 253 "" ; regex 254 outsource.example.com. ; replacement 255 ) 256 outsource.example.com. 257 ;; order pref flags 258 IN NAPTR 100 10 "u" "LIS:HELD" ( ; service 259 "!*.!https://lis.example.org:4802/?c=ex!" ; regex 260 . ; replacement 261 ) 263 Figure 3: Sample LIS:HELD Service NAPTR Records 265 Details for the "LIS" Application Service tag and the "HELD" 266 Application Protocol tag are included in Section 6. 268 An "https:" LIS URI that is a product of U-NAPTR MUST be 269 authenticated using the domain name method described in Section 3.1 270 of RFC 2818 [RFC2818]. 272 3.1. Determining a Domain Name 274 The U-NAPTR discovery method described requires a domain name as 275 input. This document does not specify how that domain name is 276 acquired by a device. If a device knows one or more domain names 277 that might be used for discovery, it is able to attempt to use each 278 domain name as input to the U-NAPTR discovery process. Static 279 configuration of a device is possible if a domain name is known to 280 work for this purpose. 282 A fully qualified domain name (FQDN) for the device might be provided 283 by a DHCP server ([RFC4702] for DHCPv4, [RFC4704] for DHCPv6). 284 DHCPv4 option 15 [RFC2131] could also be used as a source of a domain 285 name suffix for the device. If DHCP and any of these options are 286 available, these values could be used as input the U-NAPTR procedure; 287 however, implementers need to be aware that many DHCP servers do not 288 provide a sensible value for these options. Therefore, this method 289 of discovery SHOULD be given lesser precedence than methods that are 290 based on more explicit assurances. 292 4. Overall Discovery Procedure 294 The individual components of discovery are combined into a single 295 discovery procedure. Some networks maintain a topology analogous to 296 an onion and are comprised of layers, or segments, separating devices 297 from the Internet through intermediate networks. Applying the 298 individual discovery methods in an order that favours a physically 299 proximate LIS over a remote LIS is preferred. 301 A device MUST support DHCP discovery, where applicable. Devices 302 SHOULD support U-NAPTR discovery unless no input domain names can be 303 determined. 305 The following process ensures a greater likelihood of a LIS in close 306 physical proximity being discovered: 308 1. Request the DHCP LIS URI Option for each network interface. 310 2. Use U-NAPTR to discover a LIS URI using all known domain names. 312 3. Use a statically configured LIS URI. 314 A device that has multiple network interfaces could potentially be 315 served by a different access network on each interface, each with a 316 different LIS. The device SHOULD attempt to discover the LIS 317 applicable to each network interface, stopping when a LIS is 318 successfully discovered on any interface. 320 A device that discovers a LIS URI MUST attempt to verify that the LIS 321 is able to provide location information. For the HELD protocol, the 322 device MUST make a location request to the LIS. If - at any time - 323 the LIS responds to a request with the "notLocatable" error code (see 324 Section 4.3.2 of [I-D.ietf-geopriv-http-location-delivery]), the 325 device MUST continue or restart the discovery process. A device 326 SHOULD NOT make further requests to a LIS that provides a 327 "notLocatable" error until its network attachment changes, or it 328 discovers the LIS on an alternative network interface. 330 DHCP discovery MUST be attempted before any other discovery method. 331 This allows the network access provider a direct and explicit means 332 of configuring a LIS address. Alternative methods are only specified 333 as a means to discover a LIS where the DHCP infrastructure does not 334 support the LIS URI option. 336 This document does not mandate any particular source for the domain 337 name that is used as input to U-NAPTR. 339 Static configuration MAY be used if all other discovery methods fail. 340 Note however, that if a device has moved from its customary location, 341 static configuration might indicate a LIS that is unable to provide 342 accurate location information. 344 The product of the LIS discovery process is an "https:" or "http:" 345 URI. Nothing distinguishes this URI from other URIs with the same 346 scheme, aside from the fact that it is the product of this process. 347 Only URIs produced by the discovery process can be used for location 348 configuration using HELD. URIs that are not a product of LIS 349 discovery MUST NOT be used for location configuration. 351 4.1. Residential Gateways 353 The process described in this document is known to not work in a very 354 common deployment scenario. A fixed wireline scenario is described 355 in more detail in Section 3.1 of [I-D.ietf-geopriv-l7-lcp-ps]. In 356 this fixed wireline environment an intervening residential gateway 357 exists between the device and the access network. If the residential 358 gateway does not provide this option to the devices it serves, those 359 devices are unable to discover a LIS. 361 Support of this specification by residential gateways ensures that 362 the devices they serve are able to acquire location information. In 363 most cases the residential gateway configures the devices it serves 364 using DHCP. When DHCP is used, the residential gateway MUST provide 365 the devices it serves with a LIS URI option. In order to provide a 366 sensible value for this option, the residential gateway MUST either: 368 1. act as a LIS and provide location information to the devices that 369 it serves, or 371 2. discover a LIS on its external interface and relay this 372 information to devices. 374 In either case, the residential gateway provides a LIS URI option to 375 devices. 377 4.2. Virtual Private Networks (VPNs) 379 LIS discovery over a VPN network interface SHOULD NOT be performed. 380 A LIS discovered in this way is unlikely to have the information 381 necessary to determine an accurate location. 383 Not all interfaces connected to a VPN can be detected by devices or 384 the software running on them. A LIS MUST NOT provide location 385 information in response to requests that it can identify as 386 originating from a device on the remote end of a VPN tunnel, unless 387 it is able to accurately determine location. The "notLocatable" HELD 388 error code can be used to indicate to a device that discovery has 389 revealed an unsuitable LIS. This ensures that even if a device 390 discovers a LIS over the VPN, it does not rely on a LIS that is 391 unable to provide accurate location information. 393 5. Security Considerations 395 The primary attack against the methods described in this document is 396 one that would lead to impersonation of a LIS. The LIS is 397 responsible for providing location information and this information 398 is critical to a number of network services; furthermore, a device 399 does not necessarily have a prior relationship with a LIS. Several 400 methods are described here that can limit the probablity of, or 401 provide some protection against, such an attack. 403 The address of a LIS is usually well-known within an access network; 404 therefore, interception of messages does not introduce any specific 405 concerns. 407 An attacker that is able to modify or spoof messages from a DHCP 408 server could provide a falsified LIS URI that a device would be able 409 to use to successfully authenticate the LIS. Preventing DHCP 410 messages from being modified or spoofed by attackers is necessary if 411 this information is to be relied upon. Physical or link layer 412 security are commonplace methods that can reduce the possibility of 413 such an attack within an access network; alternatively, DHCP 414 authentication [RFC3118] can provide a degree of protection against 415 modification or spoofing. 417 An attacker could attempt to compromise the U-NAPTR resolution. A 418 more thorough description of the security considerations for U-NAPTR 419 applications is included in [RFC4848]. In addition to considerations 420 related to U-NAPTR, it is important to recognize that the output of 421 U-NAPTR discovery is entirely dependent on its input. An attacker 422 who can control the domain name is therefore able to control the 423 final URI. 425 A LIS that is identified by an "http:" URI cannot be authenticated. 426 Use of HTTP also does not meet requirements in HELD for 427 confidentiality and integrity. If an "http:" URI is the product of 428 DHCP or U-NAPTR discovery, this leaves devices vulnerable to several 429 attacks. Lower layer protections, such as layer 2 traffic separation 430 might provide some guarantees. 432 6. IANA Considerations 434 6.1. Registration of DHCPv4 and DHCPv6 LIS URI Option Codes 436 The IANA has assigned an option code of (TBD) for the DHCPv4 option 437 for a LIS URI, as described in Section 2.1 of this document. 439 The IANA has assigned an option code of (TBD) for the DHCPv6 option 440 for a LIS URI, as described in Section 2.2 of this document. 442 6.2. Registration of a Location Server Application Service Tag 444 This section registers a new S-NAPTR/U-NAPTR Application Service tag 445 for a LIS, as mandated by [RFC3958]. 447 Application Service Tag: LIS 449 Intended usage: Identifies a service that provides a device with its 450 location information. 452 Defining publication: RFCXXXX 454 Related publications: HELD [I-D.ietf-geopriv-http-location-delivery] 455 Contact information: The authors of this document 457 Author/Change controller: The IESG 459 6.3. Registration of a Location Server Application Protocol Tag for 460 HELD 462 This section registers a new S-NAPTR/U-NAPTR Application Protocol tag 463 for the HELD [I-D.ietf-geopriv-http-location-delivery] protocol, as 464 mandated by [RFC3958]. 466 Application Service Tag: HELD 468 Intended Usage: Identifies the HELD protocol. 470 Applicable Service Tag(s): LIS 472 Terminal NAPTR Record Type(s): U 474 Defining Publication: RFCXXXX 476 Related Publications: HELD [I-D.ietf-geopriv-http-location-delivery] 478 Contact Information: The authors of this document 480 Author/Change Controller: The IESG 482 7. Acknowledgements 484 The authors would like to thank Leslie Daigle for her work on 485 U-NAPTR; Peter Koch for feedback on how not to use DNS for discovery; 486 Andy Newton for constructive suggestions with regards to document 487 direction; Hannes Tschofenig and Richard Barnes for input and 488 reviews; Dean Willis for constructive feedback. 490 8. References 492 8.1. Normative References 494 [RFC2131] Droms, R., "Dynamic Host 495 Configuration Protocol", 496 RFC 2131, March 1997. 498 [RFC2818] Rescorla, E., "HTTP Over 499 TLS", RFC 2818, May 2000. 501 [RFC3315] Droms, R., Bound, J., 502 Volz, B., Lemon, T., 503 Perkins, C., and M. 504 Carney, "Dynamic Host 505 Configuration Protocol for 506 IPv6 (DHCPv6)", RFC 3315, 507 July 2003. 509 [RFC3396] Lemon, T. and S. Cheshire, 510 "Encoding Long Options in 511 the Dynamic Host 512 Configuration Protocol 513 (DHCPv4)", RFC 3396, 514 November 2002. 516 [RFC4702] Stapp, M., Volz, B., and 517 Y. Rekhter, "The Dynamic 518 Host Configuration 519 Protocol (DHCP) Client 520 Fully Qualified Domain 521 Name (FQDN) Option", 522 RFC 4702, October 2006. 524 [RFC4704] Volz, B., "The Dynamic 525 Host Configuration 526 Protocol for IPv6 (DHCPv6) 527 Client Fully Qualified 528 Domain Name (FQDN) 529 Option", RFC 4704, 530 October 2006. 532 [RFC4848] Daigle, L., "Domain-Based 533 Application Service 534 Location Using URIs and 535 the Dynamic Delegation 536 Discovery Service (DDDS)", 537 RFC 4848, April 2007. 539 [I-D.ietf-geopriv-http-location-delivery] Barnes, M., Winterbottom, 540 J., Thomson, M., and B. 541 Stark, "HTTP Enabled 542 Location Delivery (HELD)", 543 draft-ietf-geopriv-http- 544 location-delivery-13 (work 545 in progress), 546 February 2009. 548 [RFC2119] Bradner, S., "Key words 549 for use in RFCs to 550 Indicate Requirement 551 Levels", BCP 14, RFC 2119, 552 March 1997. 554 8.2. Informative References 556 [RFC3118] Droms, R. and W. Arbaugh, 557 "Authentication for DHCP 558 Messages", RFC 3118, 559 June 2001. 561 [RFC3693] Cuellar, J., Morris, J., 562 Mulligan, D., Peterson, 563 J., and J. Polk, "Geopriv 564 Requirements", RFC 3693, 565 February 2004. 567 [RFC3958] Daigle, L. and A. Newton, 568 "Domain-Based Application 569 Service Location Using SRV 570 RRs and the Dynamic 571 Delegation Discovery 572 Service (DDDS)", RFC 3958, 573 January 2005. 575 [I-D.ietf-geopriv-l7-lcp-ps] Tschofenig, H. and H. 576 Schulzrinne, "GEOPRIV 577 Layer 7 Location 578 Configuration Protocol; 579 Problem Statement and 580 Requirements", draft-ietf- 581 geopriv-l7-lcp-ps-09 (work 582 in progress), 583 February 2009. 585 [I-D.ietf-geopriv-lbyr-requirements] Marshall, R., 586 "Requirements for a 587 Location-by-Reference 588 Mechanism", draft-ietf- 589 geopriv-lbyr-requirements- 590 07 (work in progress), 591 February 2009. 593 Authors' Addresses 595 Martin Thomson 596 Andrew 597 PO Box U40 598 Wollongong University Campus, NSW 2500 599 AU 601 Phone: +61 2 4221 2915 602 EMail: martin.thomson@andrew.com 603 URI: http://www.andrew.com/ 605 James Winterbottom 606 Andrew 607 PO Box U40 608 Wollongong University Campus, NSW 2500 609 AU 611 Phone: +61 2 4221 2938 612 EMail: james.winterbottom@andrew.com 613 URI: http://www.andrew.com/