SIPPING WG V. Gurbani, Ed. Internet-Draft Bell Laboratories, Alcatel-Lucent Intended status: Informational C. Boulton Expires: November 5, 2007 Ubiquity Software Corporation R. Sparks Estacado Systems May 4, 2007 Session Initiation Protocol (SIP) Torture Test Messages for Internet Protocol Version 6 (IPv6) draft-ietf-sipping-ipv6-torture-tests-03 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on November 5, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This informational document provides examples of Session Initiation Protocol (SIP) test messages designed to exercise and "torture" the code of a SIP implementation that parses IPv6 addresses. Gurbani, et al. Expires November 5, 2007 [Page 1] Internet-Draft SIP IPv6 Torture Tests May 2007 This work is being discussed on the sipping@ietf.org mailing list. Table of Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Document conventions . . . . . . . . . . . . . . . . . . . . . 3 3. SIP and IPv6 network configuration . . . . . . . . . . . . . . 4 4. Parser torture tests . . . . . . . . . . . . . . . . . . . . . 4 4.1. Valid SIP message with an IPv6 reference . . . . . . . . . 5 4.2. Invalid SIP message with an IPv6 reference . . . . . . . . 5 4.3. Port ambiguous in a URI . . . . . . . . . . . . . . . . . 6 4.4. Port unambiguous in a URI . . . . . . . . . . . . . . . . 6 4.5. IPv6 reference delimiters in Via header addresses . . . . 7 4.6. SIP request with IPv6 addresses in Session Description Protocol (SDP) body . . . . . . . . . . . . . . . . . . . 8 4.7. Multiple IP addresses in SIP headers . . . . . . . . . . . 9 4.8. Multiple IP addresses in SDP . . . . . . . . . . . . . . . 10 5. Security considerations . . . . . . . . . . . . . . . . . . . 10 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative references . . . . . . . . . . . . . . . . . . . 11 8.2. Informative references . . . . . . . . . . . . . . . . . . 11 Appendix A. Bit-exact archive of each test message . . . . . . . 12 A.1. Encoded reference messages . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 15 Gurbani, et al. Expires November 5, 2007 [Page 2] Internet-Draft SIP IPv6 Torture Tests May 2007 1. Overview This document is informational, and is NOT NORMATIVE on any aspect of SIP. This document contains test messages based on the current version (2.0) of the Session Initiation Protocol as defined in [RFC3261]. This document is expected to be used as a companion document to the more general SIP torture test document [RFC4475], which does not include specific tests for IPv6 network identifiers. This document does not attempt to catalog every way to make an invalid message, nor does it attempt to be comprehensive in exploring unusual, but valid, messages. Instead, it tries to focus on areas that may cause interoperability problems in IPv6 deployments. 2. Document conventions This document contains many example SIP messages. The appendix contains an encoded binary form containing the bit-exact representation of the messages and the algorithm needed to decode them into separate files. The IPv6 addresses used in this document correspond to the 2001: DB8::/32 address prefix reserved for documentation [RFC3489]. Likewise, the IPv4 addresses used in this document correspond to the 192.0.2.0/24 address block as described in [RFC3330]. Although SIP is a text-based protocol, some of these examples cannot be unambiguously rendered without additional markup due to the constraints placed on the formatting of RFCs. This document uses the markup convention established in [RFC4475] to avoid ambiguity and meet the Internet-Draft layout requirements. For the sake of completeness, the text defining this markup from Section 2.1 of [RFC4475] is reproduced in its entirety below: "Several of these examples contain unfolded lines longer than 72 characters. These are captured between tags. The single unfolded line is reconstructed by directly concatenating all lines appearing between the tags (discarding any line feeds or carriage returns). There will be no whitespace at the end of lines. Any whitespace appearing at a fold-point will appear at the beginning of a line. "The following represent the same string of bits: Gurbani, et al. Expires November 5, 2007 [Page 3] Internet-Draft SIP IPv6 Torture Tests May 2007 Header-name: first value, reallylongsecondvalue, third value Header-name: first value, reallylongsecondvalue , third value Header-name: first value, reallylong second value, third value "Note that this is NOT SIP header-line folding, where different strings of bits have equivalent meaning." 3. SIP and IPv6 network configuration System-level issues like deploying a dual-stack proxy server, populating DNS with A and AAAA Resource Records (RRs), zero- configuration discovery of outbound proxies for IPv4 and IPv6 networks, when should a dual-stack proxy Record-Route itself, and media issues also play a major part in the transition to IPv6. This document does not, however, address these issues. Instead, a companion document [ID.sip-trans] provides more guidance on these issues. 4. Parser torture tests The test messages are organized into several sections. Some stress only a SIP parser and others stress both the parser and the application above it. Some messages are valid, and some are not. Each example clearly calls out what makes any invalid messages incorrect. Please refer to the complete Augmented Backus-Naur Form (ABNF) in [RFC3261] on representing IPv6 references in SIP. IPv6 references are delimited by a "[" and "]". When an IPv6 reference is part of a SIP Uniform Resource Identifier (URI), RFC3261 mandates that the "IPv6reference" production rule be used to recognize tokens that comprise an IPv6 reference. More specifically, the ABNF states: Gurbani, et al. Expires November 5, 2007 [Page 4] Internet-Draft SIP IPv6 Torture Tests May 2007 SIP-URI = "sip:" [ userinfo ] hostport uri-parameters [ headers ] hostport = host [ ":" port ] host = hostname / IPv4address / IPv6reference IPv6reference = "[" IPv6address "]" IPv6address = hexpart [ ":" IPv4address ] hexpart = hexseq / hexseq "::" [ hexseq ] / "::" [ hexseq ] hexseq = hex4 *( ":" hex4) hex4 = 1*4HEXDIG 4.1. Valid SIP message with an IPv6 reference The request below is well-formatted according to the grammar in [RFC3261]. An IPv6 reference appears in the Request-URI (R-URI), Via header field, and Contact header field. Message Details: ipv6-good REGISTER sip:[2001:db8::10] SIP/2.0 To: sip:user@example.com From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Max-Forwards: 70 Contact: "Caller" CSeq: 98176 REGISTER Content-Length: 0 4.2. Invalid SIP message with an IPv6 reference The request below is not well-formatted according to the grammar in [RFC3261]. The IPv6 reference in the R-URI does not contain the mandated delimiters for an IPv6 reference ("[" and "]"). An element receiving this request should respond with a 400 Bad Request error. Message Details: ipv6-bad REGISTER sip:2001:db8::10 SIP/2.0 To: sip:user@example.com From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Max-Forwards: 70 Contact: "Caller" CSeq: 98176 REGISTER Gurbani, et al. Expires November 5, 2007 [Page 5] Internet-Draft SIP IPv6 Torture Tests May 2007 Content-Length: 0 4.3. Port ambiguous in a URI IPv6 uses the colon to delimit octets. This may lead to ambiguity if the port number on which to contact a SIP server is inadvertently conflated with the IPv6 reference. Consider the REGISTER request below. The sender of the request intended to specify a port number (5070) to contact a server, but inadvertently, inserts the port number inside the closing "]" of the IPv6 reference. Unfortunately, since the IPv6 address in the R-URI is compressed, the intended port number becomes the last octet of the reference. From a parsing perspective, the request below is well-formed. However, from a semantic point of view, it will not yield the desired result. Implementations must ensure that when a raw IPv6 address appears in a SIP URI, then a port number, if required, appears outside the closing "]" delimiting the IPv6 reference. Raw IPv6 addresses can appear in the "sent-by" production rule of the Via header field, the Contact header field, the Route and Record-Route headers, among other headers. Implementers are urged to consult the ABNF in [RFC3261] for a complete list of fields where a SIP URI can appear. Message Details: port-ambiguous REGISTER sip:[2001:db8::10:5070] SIP/2.0 To: sip:user@example.com From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Contact: "Caller" Max-Forwards: 70 CSeq: 98176 REGISTER Content-Length: 0 4.4. Port unambiguous in a URI In contrast to the example in Section 4.3, the following REGISTER request leaves no ambiguity whatsoever on where the IPv6 address ends and the port number begins. This REGISTER request is well formatted per the grammar in [RFC3261]. Message Details: port-unambiguous Gurbani, et al. Expires November 5, 2007 [Page 6] Internet-Draft SIP IPv6 Torture Tests May 2007 REGISTER sip:[2001:db8::10]:5070 SIP/2.0 To: sip:user@example.com From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Contact: "Caller" Max-Forwards: 70 CSeq: 98176 REGISTER Content-Length: 0 4.5. IPv6 reference delimiters in Via header addresses IPv6 references can also appear in Via header fields; more specifically in the "sent-by" production rule and the "via-received" production rule. In the "sent-by" production rule, the sequence of octets comprising the IPv6 address is defined to appear as an "IPv6reference" non-terminal, thereby mandating the "[" and "]" delimiters. However, this is not the case for the "via-received" non-terminal. The "via-received" production rule is defined thusly: via-received = "received" EQUAL (IPv4address / IPv6address) The "IPv6address" non-terminal is defined not to include the delimiting "[" and "]". This has lead to the situation documented during the 18th SIP Interoperability Event [Email-SIPit]: Those testing IPv6 made different assumptions about enclosing literal v6 addresses in Vias in []. By the end of the event, most implementations were accepting either. Its about 50/50 on what gets sent. While it would be beneficial if the same non-terminal ("IPv6reference") was used for both the "sent-by" and "via-received" production rules, there has not been a consensus in the working group to that effect. Thus, the best that can be suggested is that implementations must follow the Robustness Principle [RFC1122] and be liberal in accepting a "received" parameter with or without the delimiting "[" and "]" tokens. When sending a request, implementations must not put the delimiting "[" and "]" tokens. The two test cases below are designed to stress this behavior. An element receiving either of these messages must parse them successfully. The request below contains an IPv6 address in the Via received parameter. The IPv6 address is delimited by "[" and "]". Even though this is not a valid request based on a strict interpretation Gurbani, et al. Expires November 5, 2007 [Page 7] Internet-Draft SIP IPv6 Torture Tests May 2007 of the grammar in [RFC3261], robust implementations must nonetheless be able to parse the topmost Via header field and continue processing the request. Message Details: via-received-param-with-delim BYE sip:[2001:db8::10] SIP/2.0 To: sip:user@example.com;tag=bd76ya From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];received=[2001:db8::9:255]; branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Max-Forwards: 70 CSeq: 321 BYE Content-Length: 0 The OPTIONS request below contains an IPv6 address in the Via received parameter without the adorning "[" and "]". This request is valid according to the grammar in [RFC3261]. Message Details: via-received-param-no-delim OPTIONS sip:[2001:db8::10] SIP/2.0 To: sip:user@example.com From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];received=2001:db8::9:255; branch=z9hG4bKas3 Call-ID: SSG95523997077@hlau_4100 Max-Forwards: 70 Contact: "Caller" CSeq: 921 OPTIONS Content-Length: 0 4.6. SIP request with IPv6 addresses in Session Description Protocol (SDP) body This request below is valid and well-formed according to the grammar in [RFC3261]. Note that the IPv6 addresses in the SDP [RFC4566] body do not have the delimiting "[" and "]". Message Details: ipv6-in-sdp Gurbani, et al. Expires November 5, 2007 [Page 8] Internet-Draft SIP IPv6 Torture Tests May 2007 INVITE sip:user@[2001:db8::10] SIP/2.0 To: sip:user@[2001:db8::10] From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::20];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Contact: "Caller" CSeq: 8612 INVITE Max-Forwards: 70 Content-Type: application/sdp Content-Length: 268 v=0 o=assistant 971731711378798081 0 IN IP6 2001:db8::20 s=Live video feed for today's meeting c=IN IP6 2001:db8::20 t=3338481189 3370017201 m=audio 6000 RTP/AVP 2 a=rtpmap:2 G726-32/8000 m=video 6024 RTP/AVP 107 a=rtpmap:107 H263-1998/90000 4.7. Multiple IP addresses in SIP headers Th request below is valid and well-formed according to the grammar in [RFC3261]. The Via list contains a mix of IPv4 addresses and IPv6 references. Message Details: mult-ip-in-header BYE sip:user@host.example.net SIP/2.0 Via: SIP/2.0/UDP [2001:db8::9:1]:6050;branch=z9hG4bKas3-111 Via: SIP/2.0/UDP 192.0.2.1;branch=z9hG4bKjhja8781hjuaij65144 Via: SIP/2.0/TCP [2001:db8::9:255];branch=z9hG4bK451jj; received=192.0.2.200 Call-ID: 997077@lau_4100 Max-Forwards: 70 CSeq: 89187 BYE To: sip:user@example.net;tag=9817--94 From: sip:user@example.com;tag=81x2 Content-Length: 0 Gurbani, et al. Expires November 5, 2007 [Page 9] Internet-Draft SIP IPv6 Torture Tests May 2007 4.8. Multiple IP addresses in SDP The request below is valid and well-formed according to the grammar in [RFC3261]. The SDP contains multiple media lines, and each media line is identified by a different network connection address. Message Details: mult-ip-in-sdp INVITE sip:user@[2001:db8::10] SIP/2.0 To: sip:user@[2001:db8::10] From: sip:user@example.com;tag=81x2 Via: SIP/2.0/UDP [2001:db8::9:1];branch=z9hG4bKas3-111 Call-ID: SSG9559905523997077@hlau_4100 Contact: "Caller" Max-Forwards: 70 CSeq: 8912 INVITE Content-Type: application/sdp Content-Length: 181 v=0 o=bob 280744730 28977631 IN IP4 host.example.com s= t=0 0 m=audio 22334 RTP/AVP 0 c=IN IP4 192.0.2.1 m=video 6024 RTP/AVP 107 c=IN IP6 2001:db8::1 a=rtpmap:107 H263-1998/90000 5. Security considerations This document presents NON-NORMATIVE examples of SIP session establishment. The security considerations in [RFC3261] apply. Parsers must carefully consider edge conditions and malicious input as part of their design. Attacks on many Internet systems use crafted input to cause implementations to behave in undesirable ways. Many of the messages in this draft are designed to stress a parser implementation at points traditionally used for such attacks. This document does not, however, attempt to be comprehensive. It contains some common pitfalls that the authors have discovered while parsing IPv6 identifiers in SIP implementations. 6. IANA considerations This document does not contain any actions for IANA. Gurbani, et al. Expires November 5, 2007 [Page 10] Internet-Draft SIP IPv6 Torture Tests May 2007 7. Acknowledgments The authors thank Jeroen van Bemmel, Dennis Bijwaard, Gonzalo Camarillo, Bob Gilligan, Alan Jeffrey, Larry Kollasch, Erik Nordmark, Kumiko Ono, Pekka Pessi, and other members of the SIP-related working groups for input provided during the construction of the document and discussion of the test cases. A.B. Nataraju and A.C. Mahendran provided working group last call comments. 8. References 8.1. Normative references [RFC1122] Braden, R., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC3330] IANA, "Special-Use IPv4 Addresses", RFC 3330, September 2002. [RFC3489] Rosenberg, J., Weinberger, J., Huitema, C., and R. Mahy, "STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs)", RFC 3489, March 2003. [RFC4475] Sparks, R., Hawrylyshen, A., Johnston, A., Rosenberg, J., and H. Schulzrinne, "Session Initiation Protocol (SIP) Torture Test Messages", RFC 4475, May 2006. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006. 8.2. Informative references [ID.sip-trans] Camarillo, G., El Malki, K., and V. Gurbani, "IPv6 Transition in the Session Initiation Protocol (SIP)", draft-ietf-sipping-v6-transition-04.txt (work in progress), September 2006. [Email-SIPit] Gurbani, et al. Expires November 5, 2007 [Page 11] Internet-Draft SIP IPv6 Torture Tests May 2007 Sparks, R., "preliminary report: SIPit 18", Electronic Mail archived at http://www1.ietf.org/mail-archive/web/ sip/current/msg14103.html, April 2006. Appendix A. Bit-exact archive of each test message The following text block is an encoded, gzip compressed TAR archive of files that represent each of the example messages discussed in Section 4. To recover the compressed archive file intact, the text of this document may be passed as input to the following Perl script (the output should be redirected to a file or piped to "tar -xzvf -"). #!/usr/bin/perl use strict; my $bdata = ""; use MIME::Base64; while(<>) { if (/-- BEGIN MESSAGE ARCHIVE --/ .. /-- END MESSAGE ARCHIVE --/) { if ( m/^\s*[^\s]+\s*$/) { $bdata = $bdata . $_; } } } print decode_base64($bdata); Alternatively, the base-64 encoded block can be edited by hand to remove document structure lines and fed as input to any base-64 decoding utility. A.1. Encoded reference messages Gurbani, et al. Expires November 5, 2007 [Page 12] Internet-Draft SIP IPv6 Torture Tests May 2007 -- BEGIN MESSAGE ARCHIVE -- H4sICN2EHkYAA2FyY2hpdmUudGFyAO1ZXXPiNhTNs3+FZl/65KAry5Ll1J202WzKd LvLBJqZTifTEdiLTfFHbcMm++tXNjEQAjhpgN0mPi8YJPnaQufco6sgmTK9L92jPQ IDxozSI4wxcIaLz+Ly7hNjSo0jwAxzEwPhXP0OhAI5wvt8qAqTLJepCjn9Z7i1X5z 7XrqlffYm1cvx3T7k/nB5ftHu9s4vURYkNlEzb7t9y7YBo2670yLHWOvFdtk4ybz0 1LuRYTL2jgdxqL1L43B900kuh44FN0S7CqRd3an1x9sO+msRQ9hwfdJPZTTwnS/Cv 6D932Rm6ACgncnxWG+/VUO7F8I0hcCmSQwhOOb81B/Lyd9UrSntd3mjv4vTzzJ1Mx txrJ3FUS4HuY3eFHfw0jfox+L5BuWX06XYcP2Tdtb1/rWRsNSaRNU0lHfwolx/70X D3LcR1rRv/RftFUHB/2Ec71MA6vlvLvhPaMl/hlnD/wPgHv+XCYKvGwV4BQpQ8j+I 9MxN9hajhv+AOan4TzAr87+BTaPh/wHQ/nDV7p0vOPwYCbjf59kqQPAzReDRnFeRK tJbDAiavfx6ESkkoHebeDaSSTIOBjIP4qilaPJAIAizNG3qYC12ZJYFaj1FORIcuA EcwOAWFxa2AGEVD7U7DC0/kJY574Oph6aB68Xok+e56FOcojx25e0PGQo9Lw+ioTZ w1o3NHcMwLGoBWAIZBi/4RTBooSMnbhAjplYiuux1Wj9fdRDRpJPmSSiVz0MXnDDd IC1L9VDdZ9EZJnTeXbFyMUB9Qb8Spv4VIayWKFb4SxbFV4RwMs71IClSgO9Jd6vE/ VfU+T+17ub6D6RoB0owbfT/APjlzyXx9+MsP670O/LyufzXmTibYRNvEPEHY0Goq2 NyDCsDRv5IWtwCfzSRwYiZQOn9wb2zlcDENFdTBzVhNDpJvYGnVNV1qlikSBNVNrl LIFtM5CxFCLA4UhO03gCr+SnzW2EfdV3QR+XB785cLvF/bxawjv+cszn/Ccz8n8nM hv8HwHfg/56/C3y0ARTltm8z3+eW8GkOECyoHGA/7iNiYU4pN7C6EmpxGzBzfhTdE 9hiB505ysRhhOeWjRDDWJgwXBk/ulDNzXZtjUmEOg+XxGmuy7AfDCfxJNvPGqut/5 jz/A9G2a5cs4kb/h8Am+s/ton5/6MI9KSazwbyv9YiUMn/SbRXBXgK/ymB0v8bAA3 /D4At9d9SABr+v2z+TwOpV7slPZGpDPUo1l1vHIQ7i1HLf7Y4/zVZef7DgDbnP4fA x06v/fFD99sd/8y36isb+4eSsCoHOz0OEssHQgTQ3by8eCFYw//PQe7vVAFq+U8W+ d+c7f8Z5Q3/D4Gq/vdE7pcE77uc3cody0Bdge/ZB8QlxQ1F8aKy99Lp3aBBgwYb8R U5DHG1ACoAAA== -- END MESSAGE ARCHIVE -- Authors' Addresses Vijay K. Gurbani (editor) Bell Laboratories, Alcatel-Lucent 2701 Lucent Lane Rm 9F-546 Lisle, IL 60532 USA Phone: +1 630 224 0216 Email: vkg@alcatel-lucent.com Gurbani, et al. Expires November 5, 2007 [Page 13] Internet-Draft SIP IPv6 Torture Tests May 2007 Chris Boulton Ubiquity Software Corporation Building 3 West Fawr Lane St Mellons Cardiff, South Wales CF3 5EA Email: cboulton@ubiquitysoftware.com Robert J. Sparks Estacado Systems Email: RjS@estacado.net Gurbani, et al. Expires November 5, 2007 [Page 14] Internet-Draft SIP IPv6 Torture Tests May 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Gurbani, et al. Expires November 5, 2007 [Page 15]