draft-ietf-sipcore-dns-dual-stack-02.txt   draft-ietf-sipcore-dns-dual-stack-03.txt 
SIPCORE O. Johansson SIPCORE O. Johansson
Internet-Draft Edvina AB Internet-Draft Edvina AB
Updates: RFC 6157 (if approved) G. Salgueiro Updates: RFC 6157 (if approved) G. Salgueiro
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: August 6, 2015 V. Gurbani Expires: August 4, 2016 V. Gurbani
Bell Labs, Alcatel-Lucent Bell Labs, Alcatel-Lucent
February 2, 2015 D. Worley, Ed.
Ariadne Internet Services
February 1, 2016
Locating Session Initiation Protocol (SIP) Servers in a Dual-Stack IP Locating Session Initiation Protocol (SIP) Servers in a Dual-Stack IP
Network Network
draft-ietf-sipcore-dns-dual-stack-02 draft-ietf-sipcore-dns-dual-stack-03
Abstract Abstract
RFC 3263 defines how a Session Initiation Protocol (SIP) RFC 3263 defines how a Session Initiation Protocol (SIP)
implementation, given a SIP Uniform Resource Identifier (URI), should implementation, given a SIP Uniform Resource Identifier (URI), should
locate the next hop SIP server using Domain Name System (DNS) locate the next hop SIP server using Domain Name System (DNS)
procedures. As SIP networks increasingly transition from IPv4-only procedures. As SIP networks increasingly transition from IPv4-only
to dual-stack, a quality user experience must be ensured for dual- to dual-stack, a quality user experience must be ensured for dual-
stack SIP implementations. This document supplements the DNS stack SIP implementations. This document updates the DNS procedures
procedures described in RFC 3263 for dual-stack SIP implementations described in RFC 3263 for dual-stack SIP implementations in
and ensures that they properly align to the optimizations detailed by preparation for forthcoming specifications for applying Happy
Happy Eyeballs. Eyeballs to SIP.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 6, 2015. This Internet-Draft will expire on August 4, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. DNS Procedures in a Dual-Stack Network . . . . . . . . . . . 3 4. DNS Procedures in a Dual-Stack Network . . . . . . . . . . . 4
4.1. Dual-Stack SIP UA DNS Record Lookup Procedure . . . . . . 4 4.1. Dual-Stack SIP UA DNS Record Lookup Procedure . . . . . . 4
4.2. Indicating Address Family Preference in DNS SRV Records . 4 4.2. Indicating Address Family Preference in DNS SRV Records . 5
5. Update to RFC 6157 . . . . . . . . . . . . . . . . . . . . . 5 5. Clarification of RFC 6157 . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 9. Revision History . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6 9.1. Changes from draft-ietf-sipcore-dns-dual-stack-02 to
9.2. Informative References . . . . . . . . . . . . . . . . . 6 draft-ietf-sipcore-dns-dual-stack-03 . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
The Session Initiation Protocol (SIP, [RFC3261]) and the additional The Session Initiation Protocol (SIP, [RFC3261]) and the additional
documents that extended the protocol assumed support for both IPv4 documents that extended it provide support for both IPv4 and IPv6.
and IPv6. However, this support does not fully extend to the highly However, this support does not fully extend to the highly hybridized
hybridized environments that are symptomatic of the transitional environments that are characteristic of the transitional migratory
migratory phase from IPv4 to IPv6 networks. During this phase, many phase from IPv4 to IPv6 networks. During this phase, many server and
server and client implementations run on dual-stack hosts. In such client implementations run on dual-stack hosts. In such
environments, a dual-stack host will likely suffer greater connection environments, a dual-stack host will likely suffer greater connection
delay, and by extension an inferior user experience, than an delay, and by extension an inferior user experience, than an
IPv4-only host. The need to remedy this diminished performance of IPv4-only host. The need to remedy this diminished performance of
dual-stack hosts led to the development of the Happy Eyeballs dual-stack hosts led to the development of the Happy Eyeballs
[RFC6555] algorithm, which has since been implemented in many
applications.
This document aims to provide a complete design solution by [RFC6555] algorithm, which has since been implemented in many
clarifying the DNS lookup procedures of RFC 3263[RFC3263] to ensure protocols and applications.
enhanced performance, and consequently user experience, in highly
hybridized dual-stack SIP networks. The procedures described herein
are such that a dual-stack client SHOULD look up both A and AAAA
records in DNS and then select the best way to set up a network flow.
The details of how the latter is done is considered out of scope for This document updates the DNS lookup procedures of RFC 3263[RFC3263]
this document. See the Happy Eyeballs algorithm and implementation in preparation for the specification of the application of Happy
and design considerations in RFC 6555 [RFC6555] for more information Eyeballs to SIP to provide enhanced performance, and consequently
about issues with setting up dual-stack network flows. user experience, in highly hybridized dual-stack SIP networks. The
procedures described herein are such that a dual-stack client should
look up both A and AAAA records in DNS and then select the best way
to set up a network flow. The details of how the latter is done is
considered out of scope for this document. See the Happy Eyeballs
algorithm and implementation and design considerations in RFC 6555
[RFC6555] for more information about issues with setting up dual-
stack network flows.
This document updates [RFC6157] as described in Section Section 5. This document updates [RFC6157] as described in Section Section 5.
2. Notational Conventions 2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Terminology 3. Terminology
skipping to change at page 3, line 48 skipping to change at page 4, line 10
IPv6-only UA/UAC/UAS: An IPv6-only UA/UAC/UAS supports SIP signaling IPv6-only UA/UAC/UAS: An IPv6-only UA/UAC/UAS supports SIP signaling
and media only on the IPv6 network. It does not understand IPv4 and media only on the IPv6 network. It does not understand IPv4
addresses. addresses.
IPv4/IPv6 UA/UAC/UAS: A UA/UAC/UAS that supports SIP signaling and IPv4/IPv6 UA/UAC/UAS: A UA/UAC/UAS that supports SIP signaling and
media on both IPv4 and IPv6 networks; such a UA/UAC/UAS is known media on both IPv4 and IPv6 networks; such a UA/UAC/UAS is known
(and will be referred to in this document) as a "dual-stack" (and will be referred to in this document) as a "dual-stack"
[RFC4213] UA/UAC/UAS. [RFC4213] UA/UAC/UAS.
address records: The DNS records which translate a domain name into
addresses within the address family(ies) that the UA supports, as
A RR's provide IPv4 addresses and AAAA RR's provide IPv6
addresses.
4. DNS Procedures in a Dual-Stack Network 4. DNS Procedures in a Dual-Stack Network
This specification introduces two normative DNS lookup procedures. This specification introduces two normative DNS lookup procedures.
These are designed to improve the performance of dual-stack clients These are designed to improve the performance of dual-stack clients
in IPv4/IPv6 networks. in IPv4/IPv6 networks.
4.1. Dual-Stack SIP UA DNS Record Lookup Procedure 4.1. Dual-Stack SIP UA DNS Record Lookup Procedure
Once the transport protocol has been determined, the procedure for Once the transport protocol has been determined, the procedure for
discovering an ip address if the TARGET is not a numeric IP address discovering an IP address if the TARGET is not a numeric IP address
but the port is explicitly stated in the URI, is detailed in but the port is explicitly stated in the URI, is detailed in
Section 4.2 of RFC 3263[RFC3263]. The piece relevant to to this Section 4.2 of RFC 3263[RFC3263]. The piece relevant to to this
discussion is: discussion is:
"If the TARGET was not a numeric IP address, but a port is present If the TARGET was not a numeric IP address, but a port is present
in the URI, the client performs an A or AAAA record lookup of the in the URI, the client performs an A or AAAA record lookup of the
domain name. The result will be a list of IP addresses, each of domain name. The result will be a list of IP addresses, each of
which can be contacted at the specific port from the URI and which can be contacted at the specific port from the URI and
transport protocol determined previously." transport protocol determined previously.
Section 4.2 of RFC 3263 [RFC3263] also goes on to describe the Section 4.2 of RFC 3263 [RFC3263] also goes on to describe the
complete procedure for discovering an ip address if the TARGET is not procedure for discovering an IP address if the TARGET is not a
a numeric IP address, and no port is present in the URI. The piece numeric IP address, and no port is present in the URI. The piece
relevant to to this discussion is: relevant to to this discussion is:
"If no SRV records were found, the client performs an A or AAAA If no SRV records were found, the client performs an A or AAAA
record lookup of the domain name. The result will be a list of IP record lookup of the domain name. The result will be a list of IP
addresses, each of which can be contacted using the transport addresses, each of which can be contacted using the transport
protocol determined previously, at the default port for that protocol determined previously, at the default port for that
transport. Processing then proceeds as described above for an transport. Processing then proceeds as described above for an
explicit port once the A or AAAA records have been looked up." explicit port once the A or AAAA records have been looked up.
Happy Eyeballs [RFC6555] has proven that looking up the "A or AAAA Happy Eyeballs [RFC6555] documents that looking up the "A or AAAA
record" is not an effective practice for dual-stack clients and that record" is not an effective practice for dual-stack clients and that
it can add significant connection delay and greatly degrade user it can add significant connection delay and greatly degrade user
experience. Therefore, this document makes the following normative experience. Therefore, this document makes the following normative
addendum to the DNS lookup procedures of Section 4.2 of RFC 3263 addendum to the DNS lookup procedures of Section 4.2 of RFC 3263
[RFC3263] for IPv4/IPv6 hybrid SIP networks and recommends it as a [RFC3263] for IPv4/IPv6 hybrid SIP networks and recommends it as a
best practice for such dual-stack networks: best practice for such dual-stack networks:
The dual-stack client SHOULD perform an A and AAAA record lookup The dual-stack client SHOULD look up all address records (i.e.,
of the domain name and add the respective IPv4/IPv6 addresses to for all address family(ies) that it supports) for the domain name
the list of IP addresses to be contacted. and add the resulting addresses to the list of IP addresses to be
contacted. A client MUST be prepared for DNS lookups to return
addresses in families that it does not support; such addresses
MUST be ignored as unusable and the supported addresses used as
specified herein.
4.2. Indicating Address Family Preference in DNS SRV Records 4.2. Indicating Address Family Preference in DNS SRV Records
The Happy Eyeballs algorithm [RFC6555] is particularly effective when The Happy Eyeballs algorithm [RFC6555] is particularly effective when
dual-stack client applications have significant performance dual-stack client applications have significant performance
differences in their IPv4 or IPv6 network paths. In this common differences in their IPv4 or IPv6 network paths. In this common
scenario it is often necessary for a dual-stack client to indicate a scenario it is often necessary for a dual-stack client to indicate a
preference for either IPv4 or IPv6. A service may use DNS SRV preference for either IPv4 or IPv6. A service may use DNS SRV
records to indicate such a preference for an address family. This records to indicate such a preference for an address family. This
way, a server with a high-latency and/or low-capacity IPv4 tunnel may way, a server with a high-latency and/or low-capacity IPv4 tunnel may
indicate a preference for being contacted using IPv6. A server that indicate a preference for being contacted using IPv6. A server that
wishes to do this can use the lowest SRV priority to publish wishes to do this can use the lowest SRV priority to publish
hostnames that only resolve in IPv6 and the next priority with host hostnames that only resolve in IPv6 and the next priority with host
names that resolve in both address families. names that resolve in both address families.
When indicating address family preference through SRV, IPv4-only and/ 5. Clarification of RFC 6157
or IPv6-only clients should be prepared to handle SRV record sets
that don't resolve into an ip address in the address family used by
that client. In such a case, the client should simply proceed to the
next priority and try the hostnames in the alternate address family.
5. Update to RFC 6157
[RFC6157] defers to the Source and Destination Address Selection [RFC6157] defers to the Source and Destination Address Selection
algorithms defined in [RFC6724] (the successor of [RFC3484]) when algorithms defined in [RFC6724] (the successor of [RFC3484]) when
allowing a client to choose a specific server (c.f. Section 5 in allowing a client to choose a specific server (c.f. Section 5 in
[RFC6157]). [RFC6157]).
This document modifies the behavior of Section 5 in [RFC6157] to This document clarifies the process: If SRV lookup is successful, the
allow for an additional (and preferred) way to contact servers, as major ordering of the list of destination addresses is determined by
outlined in Section Section 4.2. Implementations MUST use the DNS the priority and weight fields of the SRV records as specified in
SRV records as described in Section Section 4.2 of this document [RFC2782]. The (minor) ordering among the destinations derived from
first before resorting to the Source and Destination Address the "target" field of a single SRV record is determined by [RFC6724].
Selection algorithms defined in [RFC6724].
6. Security Considerations 6. Security Considerations
This document introduces two new normative procedures to the existing This document introduces two new normative procedures to the existing
DNS procedures used to locate SIP servers. While both of these DNS procedures used to locate SIP servers. While both of these
procedures are optimizations designed to improve the performance of procedures are optimizations designed to improve the performance of
dual-stack clients, neither introduces any new security dual-stack clients, neither introduces any new security
considerations. considerations.
The specific security vulnerabilities, attacks and threat models of The specific security vulnerabilities, attacks and threat models of
skipping to change at page 6, line 10 skipping to change at page 6, line 22
The authors would like to acknowledge the support and contribution of The authors would like to acknowledge the support and contribution of
the SIP Forum IPv6 Working Group. This document is based on a lot of the SIP Forum IPv6 Working Group. This document is based on a lot of
tests and discussions at SIPit events, organized by the SIP Forum. tests and discussions at SIPit events, organized by the SIP Forum.
This document has benefited from the expertise and review feedback of This document has benefited from the expertise and review feedback of
many participants of the IETF DISPATCH and SIPCORE WG mailing lists many participants of the IETF DISPATCH and SIPCORE WG mailing lists
as well as those on the SIP Forum IPv6 Task Group mailing list. The as well as those on the SIP Forum IPv6 Task Group mailing list. The
authors wish to specifically call out the efforts and express their authors wish to specifically call out the efforts and express their
gratitude for the detailed and thoughtful comments and corrections of gratitude for the detailed and thoughtful comments and corrections of
Dan Wing, Brett Tate, Rifaat Shekh-Yusef, Carl Klatsky, Dale Worley, Dan Wing, Brett Tate, Rifaat Shekh-Yusef, Carl Klatsky, Mary Barnes,
Mary Barnes, Keith Drage and Cullen Jennings. Keith Drage and Cullen Jennings.
The authors also thank the SIPCORE WG chairs, Paul Kyzivat and Adam The authors also thank the SIPCORE WG chairs, Paul Kyzivat and Adam
Roach, and assigned Area Director, Richard Barnes, for their support Roach, and assigned Area Director, Richard Barnes, for their support
and thorough evaluation of this work. and thorough evaluation of this work.
9. References 9. Revision History
9.1. Normative References [Note to RFC Editor: Please remove this entire section upon
publication as an RFC.]
9.1. Changes from draft-ietf-sipcore-dns-dual-stack-02 to draft-ietf-
sipcore-dns-dual-stack-03
Revised wording, punctuation, and capitalization in various places.
Clarified that this draft does not document Happy Eyeballs for SIP,
but is preparatory for it.
Attempted to use "update" for text that is definitively a change to
the preexisting text and "clarify" for text that is a more clear
statement of the (presumed) intention of the preexisting text.
Removed normative words from section 1, the introduction.
Copied definition of "address records" from RFC 2782 (SRV records) to
allow the specifications to expand automatically to include any new
address families.
Relocated the text requiring a client to ignore addresses that it
discovers in address families it does not support from section 4.2
(which describes why the situation arises) to section 4.1 (which
describes how clients look up RRs).
Clarified the interaction with RFC 6157 (source and destination
address selection in IPv6) to specify what must have been intended:
The major sort of the destinations is the ordering determined by
priority/weight in the SRV records; the addresses derived from a
single SRV record's target are minorly sorted based on RFC 6157.
Removed editor's name from the acknowledgments list.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
DOI 10.17487/RFC2782, February 2000,
<http://www.rfc-editor.org/info/rfc2782>.
[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263, June Protocol (SIP): Locating SIP Servers", RFC 3263,
2002. DOI 10.17487/RFC3263, June 2002,
<http://www.rfc-editor.org/info/rfc3263>.
[RFC6157] Camarillo, G., El Malki, K., and V. Gurbani, "IPv6 [RFC6157] Camarillo, G., El Malki, K., and V. Gurbani, "IPv6
Transition in the Session Initiation Protocol (SIP)", RFC Transition in the Session Initiation Protocol (SIP)",
6157, April 2011. RFC 6157, DOI 10.17487/RFC6157, April 2011,
<http://www.rfc-editor.org/info/rfc6157>.
9.2. Informative References 10.2. Informative References
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002. DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>.
[RFC3484] Draves, R., "Default Address Selection for Internet [RFC3484] Draves, R., "Default Address Selection for Internet
Protocol version 6 (IPv6)", RFC 3484, February 2003. Protocol version 6 (IPv6)", RFC 3484,
DOI 10.17487/RFC3484, February 2003,
<http://www.rfc-editor.org/info/rfc3484>.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213, October 2005. for IPv6 Hosts and Routers", RFC 4213,
DOI 10.17487/RFC4213, October 2005,
<http://www.rfc-editor.org/info/rfc4213>.
[RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with [RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
Dual-Stack Hosts", RFC 6555, April 2012. Dual-Stack Hosts", RFC 6555, DOI 10.17487/RFC6555, April
2012, <http://www.rfc-editor.org/info/rfc6555>.
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown, [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6 "Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, September 2012. (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
<http://www.rfc-editor.org/info/rfc6724>.
Authors' Addresses Authors' Addresses
Olle E. Johansson Olle E. Johansson
Edvina AB Edvina AB
Runbovaegen 10 Runbovaegen 10
Sollentuna SE-192 48 Sollentuna SE-192 48
SE SE
Email: oej@edvina.net Email: oej@edvina.net
skipping to change at line 314 skipping to change at page 9, line 4
Email: gsalguei@cisco.com Email: gsalguei@cisco.com
Vijay Gurbani Vijay Gurbani
Bell Labs, Alcatel-Lucent Bell Labs, Alcatel-Lucent
1960 Lucent Lane 1960 Lucent Lane
Rm 9C-533 Rm 9C-533
Naperville, IL 60563 Naperville, IL 60563
US US
Email: vkg@bell-labs.com Email: vkg@bell-labs.com
Dale R. Worley (editor)
Ariadne Internet Services
738 Main St.
Waltham, MA 02451
US
Email: worley@ariadne.com
 End of changes. 39 change blocks. 
75 lines changed or deleted 136 lines changed or added

This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/