draft-ietf-seamoby-ctp-06.txt   draft-ietf-seamoby-ctp-07.txt 
Seamoby WG J. Loughney (editor) Seamoby WG J. Loughney (editor)
Internet Draft M. Nakhjiri Internet Draft M. Nakhjiri
Category: Experimental C. Perkins Category: Experimental C. Perkins
<draft-ietf-seamoby-ctp-06.txt> R. Koodli <draft-ietf-seamoby-ctp-07.txt> R. Koodli
Expires: July 1, 2004 January 1, 2004 Expires: July 13, 2004 January 13, 2004
Context Transfer Protocol Context Transfer Protocol
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [RFC2026]. all provisions of Section 10 of RFC2026 [RFC2026].
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 34 skipping to change at page 1, line 34
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Distribution of this memo is unlimited. Distribution of this memo is unlimited.
Copyright (C) The Internet Society 2003. All Rights Reserved. Copyright (C) The Internet Society 2004. All Rights Reserved.
Abstract Abstract
This document presents a context transfer protocol that enables This document presents a context transfer protocol that enables
authorized context transfers. Context transfers allow better support authorized context transfers. Context transfers allow better support
for node based mobility so that the applications running on mobile for node based mobility so that the applications running on mobile
nodes can operate with minimal disruption. Key objectives are to nodes can operate with minimal disruption. Key objectives are to
reduce latency, packet losses and avoiding re-initiation of signaling reduce latency, packet losses and avoiding re-initiation of signaling
to and from the mobile node. to and from the mobile node.
skipping to change at page 3, line 21 skipping to change at page 3, line 21
* Messages to initiate and authorize context transfer, and notify * Messages to initiate and authorize context transfer, and notify
a mobile node of the status of the transfer. a mobile node of the status of the transfer.
* Messages for transferring contexts prior to, during and after * Messages for transferring contexts prior to, during and after
handovers. handovers.
The proposed protocol is designed to work in conjunction with other The proposed protocol is designed to work in conjunction with other
protocols in order to provide seamless mobility. The protocol protocols in order to provide seamless mobility. The protocol
supports both IPv4 and IPv6, though support for IPv4 private supports both IPv4 and IPv6, though support for IPv4 private
addresses is for future study. addresses is for future study.
The Problem
"Problem Description: Reasons For Performing Context Transfers "Problem Description: Reasons For Performing Context Transfers
between Nodes in an IP Access Network" [RFC3374] defines the between Nodes in an IP Access Network" [RFC3374] defines the
following main reasons why Context Transfer procedures may be useful following main reasons why Context Transfer procedures may be useful
in IP networks. in IP networks.
1) The primary motivation, as mentioned in the introduction, is the 1) The primary motivation, as mentioned in the introduction, is the
need to quickly re-establish context transfer-candidate services need to quickly re-establish context transfer-candidate services
without requiring the mobile host to explicitly perform all without requiring the mobile host to explicitly perform all
protocol flows for those services from scratch. An example of a protocol flows for those services from scratch. An example of a
service is included in Appendix C. service is included in Appendix C.
skipping to change at page 8, line 16 skipping to change at page 8, line 16
Length message length in octets Length message length in octets
'P' bit 0 = No presence vector 'P' bit 0 = No presence vector
1 = Presence vector present. 1 = Presence vector present.
FPT 16 bit integer, listing the feature profile FPT 16 bit integer, listing the feature profile
type contained in the data field. type contained in the data field.
data Context type-dependent data, whose length is data Context type-dependent data, whose length is
is defined by the Length Field. If the data is defined by the Length Field. If the data
is not 64-bit aligned, the data field is padded is not 64-bit aligned, the data field is
with zeros. padded with zeros.
The Cxt-Type indicates the type of the feature context message itself The Cxt-Type indicates the type of the feature context message itself
(such as QoS Context Request, QoS Context Transfer etc.), and Feature (such as QoS Context Request, QoS Context Transfer etc.), and Feature
Profile Type (FPT) identifies the way the particular feature context Profile Type (FPT) identifies the way the particular feature context
is organized. The 'P' bit specifies whether or not the "presence is organized. The 'P' bit specifies whether or not the "presence
vector" is used. When the presence vector is in use, the Presence vector" is used. When the presence vector is in use, the Presence
Vector is interpreted to indicate whether particular data fields are Vector is interpreted to indicate whether particular data fields are
present (and containing non-default values). The ordering of the present (and containing non-default values). The ordering of the
bits in the presence vector is the same as the ordering of the data bits in the presence vector is the same as the ordering of the data
fields according to the context type specification, one bit per data fields according to the context type specification, one bit per data
skipping to change at page 11, line 24 skipping to change at page 11, line 24
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FPT (if present) | Status code | Reserved | | FPT (if present) | Status code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ........ | | ........ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type CTAR = 2 Type CTAR = 2
Length message length in octets Length message length in octets
Reserved Reserved for future use. Must be set to zero Reserved Reserved for future use. Must be set to
by the sender of CTAA Message, i.e. pAR or zero by the sender of CTAA Message, i.e.
nAR. pAR or nAR.
'V' flag When set to '00', indicate presence of IPv6 'V' flag When set to '00', indicate presence of IPv6
Previous (New) address only. Previous (New) address only.
When set to '01' indicate presence of IPv4 When set to '01' indicate presence of IPv4
Previous (New) Address only. Previous (New) Address only.
When set to '10' indicate presence of both When set to '10' indicate presence of both
IPv6 and IPv4 Previous (New) addresses. IPv6 and IPv4 Previous (New) addresses.
MN's Prev IP Address Field contains either: MN's Prev IP Address Field contains either:
IPv4 Address as defined in [RFC 791]. IPv4 Address as defined in [RFC 791].
IPv6 Address as defined in [RFC 2373]. IPv6 Address as defined in [RFC 2373].
FPT 16 bit integer, listing the FTP that was not FPT 16 bit integer, listing the FTP that
Successfully transferred. was not Successfully transferred.
Status Code An octet, containing failure reason. Status Code An octet, containing failure reason.
2.5.3 Context Transfer Data (CTD) Message 2.5.3 Context Transfer Data (CTD) Message
Sent by pAR to nAR, and includes feature data (CTP data). This Sent by pAR to nAR, and includes feature data (CTP data). This
message should handle predictive as well as normal CT. An message should handle predictive as well as normal CT. An
acknowledgement flag, A, included in this message indicates whether a acknowledgement flag, A, included in this message indicates whether a
reply is required by pAR. reply is required by pAR.
skipping to change at page 13, line 7 skipping to change at page 13, line 7
MN's Prev CoA Address Field contains either: MN's Prev CoA Address Field contains either:
IPv4 Address as defined in [RFC 791], IPv4 Address as defined in [RFC 791],
IPv6 Address as defined in [RFC 2373]. IPv6 Address as defined in [RFC 2373].
MN's New CoA Address Field contains either: MN's New CoA Address Field contains either:
IPv4 Address as defined in [RFC 791], IPv4 Address as defined in [RFC 791],
IPv6 Address as defined in [RFC 2373]. IPv6 Address as defined in [RFC 2373].
This is only applicable for the PCTD message. This is only applicable for the PCTD message.
Algorithm Algorithm for carrying out the computation of Algorithm Algorithm for carrying out the computation
the MN Authorization Token. Currently only 1 of the MN Authorization Token. Currently only
algorithm is defined, HMAC_SHA1 = 1. one algorithm is defined, HMAC_SHA1 = 1.
Key Length length of key, in octets. Key Length length of key, in octets.
When CTD is sent predictively, the supplied parameters including the When CTD is sent predictively, the supplied parameters including the
algorithm, key length and the key itself, allow nAR to compute a algorithm, key length and the key itself, allow nAR to compute a
token locally and verify against the token present in the CTAR token locally and verify against the token present in the CTAR
message. This message MUST be protected by IPsec. message. This message MUST be protected by IPsec.
As described previously, the algorithm for carrying out the As described previously, the algorithm for carrying out the
computation of the MN Authorization Token is HMAC_SHA1. The input computation of the MN Authorization Token is HMAC_SHA1. The input
skipping to change at page 13, line 51 skipping to change at page 13, line 51
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type CTDR = 5 (Context Transfer Data) Type CTDR = 5 (Context Transfer Data)
Length message length in octets Length message length in octets
'V' flag When set to '00', indicate presence of IPv6 'V' flag When set to '00', indicate presence of IPv6
Previous address only. Previous address only.
When set to '01' indicate presence of IPv4 When set to '01' indicate presence of IPv4
Previous Address only. Previous Address only.
When set to '10' indicate presence of both IPv6 When set to '10' indicate presence of both
and IPv4 Previous addresses. IPv6 and IPv4 Previous addresses.
'S' bit When set to one, this bit indicates that all 'S' bit When set to one, this bit indicates that all
the feature contexts sent in CTD or PCTD were the feature contexts sent in CTD or PCTD were
received successfully. received successfully.
Reserved Reserved for future use. Must be set to zero Reserved Reserved for future use. Must be set to zero
by the nAR. by the nAR.
MN's Prev IP Address Field contains either: MN's Prev IP Address Field contains either:
IPv4 Address as defined in [RFC 791]. IPv4 Address as defined in [RFC 791].
IPv6 Address as defined in [RFC 2373]. IPv6 Address as defined in [RFC 2373].
Status Code A context-specific return value, present when Status Code A context-specific return value, present
'S' is not set to one. when 'S' is not set to one.
FPT 16 bit integer, listing the FTP that is being FPT 16 bit integer, listing the FTP that is
acknowledged. being acknowledged.
Status Code 0 = not successfully transfered Status Code 0 = not successfully transfered
1 = successfully transfered 1 = successfully transfered
2.5.5 Context Transfer Cancel (CTC) Message 2.5.5 Context Transfer Cancel (CTC) Message
If transferring a context cannot be completed in a timely fashion, If transferring a context cannot be completed in a timely fashion,
then nAR may send CTC to pAR to cancel an ongoing CT process. then nAR may send CTC to pAR to cancel an ongoing CT process.
0 1 2 3 0 1 2 3
skipping to change at page 18, line 52 skipping to change at page 18, line 51
transfers between ARs. Another important consideration is that the transfers between ARs. Another important consideration is that the
mobile node should claim it's own context, and not some other mobile node should claim it's own context, and not some other
masquerader. One method to achieve this is to provide an masquerader. One method to achieve this is to provide an
authentication cookie to be included with the context transfer authentication cookie to be included with the context transfer
message sent from the pAR to the nAR and confirmed by the mobile node message sent from the pAR to the nAR and confirmed by the mobile node
at the nAR. at the nAR.
6.3. IPsec Considerations 6.3. IPsec Considerations
Access Routers MUST implement IPsec ESP [ESP] in transport mode with Access Routers MUST implement IPsec ESP [ESP] in transport mode with
non-null encryption and authentication algorithms to provide per- non-null encryption and authentication algorithms to provide per
packet authentication, integrity protection and confidentiality, and packet authentication, integrity protection and confidentiality, and
MUST implement the replay protection mechanisms of IPsec. In those MUST implement the replay protection mechanisms of IPsec. In those
scenarios where IP layer protection is needed, ESP in tunnel mode scenarios where IP layer protection is needed, ESP in tunnel mode
SHOULD be used. Non-null encryption should be used when using IPSec SHOULD be used. Non-null encryption should be used when using IPSec
ESP. ESP.
7. IANA Considerations 7. IANA Considerations
This section provides guidance to the Internet Assigned Numbers This section provides guidance to the Internet Assigned Numbers
Authority (IANA) regarding registration of values related to the Authority (IANA) regarding registration of values related to the
skipping to change at page 20, line 12 skipping to change at page 20, line 12
Motiwala, Phil Neumiller, Hesham Soliman and Lucian Suciu for their Motiwala, Phil Neumiller, Hesham Soliman and Lucian Suciu for their
help and suggestions with this document. help and suggestions with this document.
9. References 9. References
9.1 Normative References 9.1 Normative References
[RFC2026] S. Bradner, "The Internet Standards Process -- Revision 3", [RFC2026] S. Bradner, "The Internet Standards Process -- Revision 3",
BCP 9, RFC 2026, October 1996. BCP 9, RFC 2026, October 1996.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate Require- [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
ment Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2434] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA [RFC2434] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October Considerations Section in RFCs", BCP 26, RFC 2434, October
1998. 1998.
[RFC2409] D. Harkins, D. Carrel, "The Internet Key Exchange (IKE)", [RFC2409] D. Harkins, D. Carrel, "The Internet Key Exchange (IKE)",
RFC 2409, November 1998. RFC 2409, November 1998.
[ESP] Kent, S. and R. Atkinson, "IP Encapsulating Security Pay- [ESP] Kent, S. and R. Atkinson, "IP Encapsulating Security Pay-
load (ESP)", RFC 2406, November 1998. load (ESP)", RFC 2406, November 1998.
skipping to change at page 21, line 14 skipping to change at page 21, line 14
[TERM] J. Manner, M. Kojo, "Mobility Related Terminology", Internet [TERM] J. Manner, M. Kojo, "Mobility Related Terminology", Internet
Engineering Task Force, Work in Progress. Engineering Task Force, Work in Progress.
[RFC2710] Deering, S., Fenner, W., and Haberman, B., " Multicast [RFC2710] Deering, S., Fenner, W., and Haberman, B., " Multicast
Listener Discovery (MLD) for IPv6," RFC 2710, October, 1999. Listener Discovery (MLD) for IPv6," RFC 2710, October, 1999.
[RFC2461] Narten, T., Nordmark, E., and Simpson. W., "Neighbor Discovery [RFC2461] Narten, T., Nordmark, E., and Simpson. W., "Neighbor Discovery
for IP Version 6 (IPv6)," RFC 2461, December, 1998. for IP Version 6 (IPv6)," RFC 2461, December, 1998.
[RFC2462] Thompson, S., and Narten, T., "IPv6 Address Autoconfigura- [RFC2462] Thompson, S., and Narten, T., "IPv6 Address
tion," RFC 2462, December, 1998. Autoconfiguration," RFC 2462, December, 1998.
Appendix A. Timing and Trigger Considerations Appendix A. Timing and Trigger Considerations
Basic Mobile IP handover signaling can introduce disruptions to the Basic Mobile IP handover signaling can introduce disruptions to the
services running on top of Mobile IP, which may introduce unwanted services running on top of Mobile IP, which may introduce unwanted
latencies that practically prohibit its use for certain types of ser- latencies that practically prohibit its use for certain types of
vices. Mobile IP latency and packet loss is being optimized through services. Mobile IP latency and packet loss is being optimized through
several alternative procedures, such as Fast Mobile IP [FMIPv6] and several alternative procedures, such as Fast Mobile IP [FMIPv6] and
Low Latency Mobile IP [LLMIP]. Low Latency Mobile IP [LLMIP].
Feature re-establishment through context transfer should contribute Feature re-establishment through context transfer should contribute
zero (optimally) or minimal extra disruption of services in conjunc- zero (optimally) or minimal extra disruption of services in
tion to handovers. This means that the timing of context transfer conjunction to handovers. This means that the timing of context
SHOULD be carefully aligned with basic Mobile IP handover events, and transfer SHOULD be carefully aligned with basic Mobile IP handover
with optimized Mobile IP handover signaling mechanisms, as those pro- events, and with optimized Mobile IP handover signaling mechanisms,
tocols become available. as those protocols become available.
Furthermore, some of those optimized mobile IP handover mechanisms Furthermore, some of those optimized mobile IP handover mechanisms
may provide more flexibility is choosing the timing and order for may provide more flexibility is choosing the timing and order for
transfer of various context information. transfer of various context information.
Appendix B. Multicast Listener Context Transfer Appendix B. Multicast Listener Context Transfer
As an example of how context transfer can improve the performance of As an example of how context transfer can improve the performance of
IP layer handover, we consider transferring IPv6 MLD state [RFC2710]. IP layer handover, we consider transferring IPv6 MLD state [RFC2710].
MLD state is a particularly good example because every IPv6 node must MLD state is a particularly good example because every IPv6 node must
perform two MLD messaging sequences on the wireless link to establish perform two MLD messaging sequences on the wireless link to establish
itself as an MLD listener prior to performing router discovery itself as an MLD listener prior to performing router discovery
[RFC2461] or duplicate address detection [RFC2462] or before [RFC2461] or duplicate address detection [RFC2462] or before
sending/receiving any application-specific traffic (including Mobile sending/receiving any application-specific traffic (including Mobile
IP handover signaling, if any). The node must subscribe to the Soli- IP handover signaling, if any). The node must subscribe to the
cited Node Multicast Address as soon as it comes up on the link. Any Solicited Node Multicast Address as soon as it comes up on the link.
application-specific multicast addresses must be re-established as Any application-specific multicast addresses must be re-established as
well. Context transfer can significantly speed up re-establishing well. Context transfer can significantly speed up re-establishing
multicast state by allowing the nAR to initialize MLD for a node that multicast state by allowing the nAR to initialize MLD for a node that
just completed handover; without any MLD signaling on the new wire- just completed handover; without any MLD signaling on the new
less link. The same approach could be used for transferring multicast wireless link. The same approach could be used for transferring
context in IPv4. multicast context in IPv4.
An approximate qualitative estimate for the amount of savings in An approximate qualitative estimate for the amount of savings in
handover time can be obtained as follows. MLD messages are 24 bytes, handover time can be obtained as follows. MLD messages are 24 bytes,
to which the headers must be added, because there is no header to which the headers must be added, because there is no header
compression on the new link, with IPv6 header being 40 bytes, and a compression on the new link, with IPv6 header being 40 bytes, and a
required Router Alert Hop-by-Hop option being 8 bytes including pad- required Router Alert Hop-by-Hop option being 8 bytes including
ding. The total MLD message size is 72 bytes per subscribed multicast padding. The total MLD message size is 72 bytes per subscribed multicast
address. RFC 2710 recommends that nodes send 2 to 3 MLD Report mes- address. RFC 2710 recommends that nodes send 2 to 3 MLD Report messages
sages per address subscription, since the Report message is unack- per address subscription, since the Report message is unacknowledged.
nowledged. Assuming 2 MLD messages sent for a subscribed address, the Assuming 2 MLD messages sent for a subscribed address, the
mobile node would need to send 144 bytes per address subscription. If mobile node would need to send 144 bytes per address subscription. If
MLD messages are sent for both the All Nodes Multicast Address and MLD messages are sent for both the All Nodes Multicast Address and
the Solicited Node Multicast address for the node's link local the Solicited Node Multicast address for the node's link local
address, a total of 288 bytes are required when the node hands over address, a total of 288 bytes are required when the node hands over
to the new link. Note that some implementations of IPv6 optimize by to the new link. Note that some implementations of IPv6 optimize by
not sending an MLD message for the All Nodes Multicast Address, since not sending an MLD message for the All Nodes Multicast Address, since
the router can infer that at least one node is on the link (itself) the router can infer that at least one node is on the link (itself)
when it comes up and always will be, but for purposes of this calcu- when it comes up and always will be, but for purposes of this
lation, we assume that the IPv6 implementation is conformant and that calculation, we assume that the IPv6 implementation is conformant and
the message is sent. The amount of time required for MLD signaling that the message is sent. The amount of time required for MLD signaling
will, of course, depend on the wireless link bandwidth, but some will, of course, depend on the wireless link bandwidth, but some
representative numbers can be obtained by assuming bandwidths of 20 representative numbers can be obtained by assuming bandwidths of 20
kbps or 100 kbps. The former is approximate for a narrowband 3G cel- kbps or 100 kbps. The former is approximate for a narrowband 3G
lular links and the latter for a heavily utilized 802.11b WLAN link, cellular links and the latter for a heavily utilized 802.11b WLAN link,
both running Voice over IP (VoIP). With these two bit rates, the sav- both running Voice over IP (VoIP). With these two bit rates, the
ings from not having to perform the pre-router discovery messages are savings from not having to perform the pre-router discovery messages
115 msec. and 23 msec., respectively. If any application-specific are 115 msec. and 23 msec., respectively. If any application-specific
multicast addresses are subscribed, the amount of time saved could be multicast addresses are subscribed, the amount of time saved could be
substantially more. Considering most ATM-based 3G voice cellular pro- substantially more. Considering most ATM-based 3G voice cellular
tocols try to keep total voice handover delay less than 40-80 msec., protocols try to keep total voice handover delay less than 40-80
MLD signaling could have a large impact on the performance of inter- msec., MLD signaling could have a large impact on the performance
subnet VoIP handover. of inter-subnet VoIP handover.
The context-specific data field for MLD context transfer included in The context-specific data field for MLD context transfer included in
the CTP Context Data Block message for a single IPv6 multicast the CTP Context Data Block message for a single IPv6 multicast
address has the following format: address has the following format:
0 1 2 3 0 1 2 3
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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Subnet Prefix on nAR Wireless Interface + + Subnet Prefix on nAR Wireless Interface +
skipping to change at page 24, line 33 skipping to change at page 24, line 39
Charles E. Perkins Charles E. Perkins
Nokia Research Center Nokia Research Center
313 Fairchild Drive 313 Fairchild Drive
Mountain View, California 94043 Mountain View, California 94043
USA USA
charliep@iprg.nokia.com charliep@iprg.nokia.com
Intellectual Property Considerations Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to per- intellectual property or other rights that might be claimed to
tain to the implementation or use of the technology described in this pertain to the implementation or use of the technology described in
document or the extent to which any license under such rights might this document or the extent to which any license under such rights
or might not be available; neither does it represent that it has made might or might not be available; neither does it represent that it
any effort to identify any such rights. Information on the IETF's has made any effort to identify any such rights. Information on
procedures with respect to rights in standards-track and standards- the IETF's procedures with respect to rights in standards-track
related documentation can be found in BCP-11. Copies of claims of and standards-related documentation can be found in BCP-11. Copies
rights made available for publication and any assurances of licenses of claims of rights made available for publication and any assurances
to be made available, or the result of an attempt made to obtain a of licenses to be made available, or the result of an attempt made
general license or permission for the use of such proprietary rights to obtain a general license or permission for the use of such
by implementers or users of this specification can be obtained from proprietary rights by implementers or users of this specification
the IETF Secretariat. can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Copyright (C) The Internet Society 2004. All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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.
 End of changes. 

This html diff was produced by rfcdiff 1.25, available from http://www.levkowetz.com/ietf/tools/rfcdiff/