draft-ietf-tcpm-urgent-data-06.txt   draft-ietf-tcpm-urgent-data-07.txt 
TCP Maintenance and Minor F. Gont TCP Maintenance and Minor F. Gont
Extensions (tcpm) UTN/FRH Extensions (tcpm) UTN/FRH
Internet-Draft A. Yourtchenko Internet-Draft A. Yourtchenko
Updates: 793, 1011, 1122 Cisco Updates: 793, 1011, 1122 Cisco
(if approved) August 23, 2010 (if approved) October 16, 2010
Intended status: Standards Track Intended status: Standards Track
Expires: February 24, 2011 Expires: April 19, 2011
On the implementation of the TCP urgent mechanism On the implementation of the TCP urgent mechanism
draft-ietf-tcpm-urgent-data-06.txt draft-ietf-tcpm-urgent-data-07.txt
Abstract Abstract
This document analyzes how current TCP implementations process TCP This document analyzes how current TCP implementations process TCP
urgent indications, and how the behavior of some widely-deployed urgent indications, and how the behavior of some widely-deployed
middle-boxes affect how urgent indications are processed by end middle-boxes affect how urgent indications are processed by end
systems. This document updates the relevant specifications such that systems. This document updates the relevant specifications such that
they accommodate current practice in processing TCP urgent they accommodate current practice in processing TCP urgent
indications, provides advice to applications that make use of the indications, raises awareness about the reliability of TCP urgent
urgent mechanism, and raises awareness about the reliability of TCP indications in the Internet and recommends against the use of the
urgent indications in the current Internet. urgent indications (but provides advice to applications in case that
they do).
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF 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 February 24, 2011. This Internet-Draft will expire on April 19, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 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
skipping to change at page 2, line 18 skipping to change at page 2, line 19
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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Specification of the TCP urgent mechanism . . . . . . . . . . 4 2. Specification of the TCP urgent mechanism . . . . . . . . . . 4
2.1. Semantics of urgent indications . . . . . . . . . . . . . 4 2.1. Semantics of urgent indications . . . . . . . . . . . . . 4
2.2. Semantics of the Urgent Pointer . . . . . . . . . . . . . 5 2.2. Semantics of the Urgent Pointer . . . . . . . . . . . . . 5
2.3. Allowed length of urgent data . . . . . . . . . . . . . . 5 2.3. Allowed length of urgent data . . . . . . . . . . . . . . 5
3. Current implementation practice of TCP urgent data . . . . . . 5 3. Current implementation practice of TCP urgent data . . . . . . 6
3.1. Semantics of urgent indications . . . . . . . . . . . . . 5 3.1. Semantics of urgent indications . . . . . . . . . . . . . 6
3.2. Semantics of the Urgent Pointer . . . . . . . . . . . . . 6 3.2. Semantics of the Urgent Pointer . . . . . . . . . . . . . 6
3.3. Allowed length of urgent data . . . . . . . . . . . . . . 6 3.3. Allowed length of urgent data . . . . . . . . . . . . . . 7
3.4. Interaction of middle-boxes with TCP urgent indications . 7 3.4. Interaction of middle-boxes with TCP urgent indications . 7
4. Updating RFC 793, RFC 1011, and RFC 1122 . . . . . . . . . . . 7 4. Updating RFC 793, RFC 1011, and RFC 1122 . . . . . . . . . . . 7
5. Advice to new applications employing TCP . . . . . . . . . . . 7 5. Advice to new applications employing TCP . . . . . . . . . . . 8
6. Advice to applications that make use of the urgent 6. Advice to applications that make use of the urgent
mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 8 mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . . 9
Appendix A. Survey of the processing of TCP urgent Appendix A. Survey of the processing of TCP urgent
indications by some popular TCP implementations . . . 10 indications by some popular TCP implementations . . . 10
A.1. FreeBSD . . . . . . . . . . . . . . . . . . . . . . . . . 10 A.1. FreeBSD . . . . . . . . . . . . . . . . . . . . . . . . . 10
A.2. Linux . . . . . . . . . . . . . . . . . . . . . . . . . . 10 A.2. Linux . . . . . . . . . . . . . . . . . . . . . . . . . . 11
A.3. NetBSD . . . . . . . . . . . . . . . . . . . . . . . . . . 10 A.3. NetBSD . . . . . . . . . . . . . . . . . . . . . . . . . . 11
A.4. OpenBSD . . . . . . . . . . . . . . . . . . . . . . . . . 11 A.4. OpenBSD . . . . . . . . . . . . . . . . . . . . . . . . . 11
A.5. Cisco IOS software . . . . . . . . . . . . . . . . . . . . 11 A.5. Cisco IOS software . . . . . . . . . . . . . . . . . . . . 12
A.6. Microsoft Windows 2000, Service Pack 4 . . . . . . . . . . 11 A.6. Microsoft Windows 2000, Service Pack 4 . . . . . . . . . . 12
A.7. Microsoft Windows 2008 . . . . . . . . . . . . . . . . . . 11 A.7. Microsoft Windows 2008 . . . . . . . . . . . . . . . . . . 12
A.8. Microsoft Windows 95 . . . . . . . . . . . . . . . . . . . 12 A.8. Microsoft Windows 95 . . . . . . . . . . . . . . . . . . . 12
Appendix B. Changes from previous versions of the draft (to Appendix B. Changes from previous versions of the draft (to
be removed by the RFC Editor before publishing be removed by the RFC Editor before publishing
this document as an RFC) . . . . . . . . . . . . . . 12 this document as an RFC) . . . . . . . . . . . . . . 12
B.1. Changes from draft-ietf-tcpm-urgent-data-05 . . . . . . . 12 B.1. Changes from draft-ietf-tcpm-urgent-data-06 . . . . . . . 12
B.2. Changes from draft-ietf-tcpm-urgent-data-04 . . . . . . . 12 B.2. Changes from draft-ietf-tcpm-urgent-data-05 . . . . . . . 13
B.3. Changes from draft-ietf-tcpm-urgent-data-03 . . . . . . . 12 B.3. Changes from draft-ietf-tcpm-urgent-data-04 . . . . . . . 13
B.4. Changes from draft-ietf-tcpm-urgent-data-02 . . . . . . . 12 B.4. Changes from draft-ietf-tcpm-urgent-data-03 . . . . . . . 13
B.5. Changes from draft-ietf-tcpm-urgent-data-01 . . . . . . . 12 B.5. Changes from draft-ietf-tcpm-urgent-data-02 . . . . . . . 13
B.6. Changes from draft-ietf-tcpm-urgent-data-00 . . . . . . . 12 B.6. Changes from draft-ietf-tcpm-urgent-data-01 . . . . . . . 13
B.7. Changes from draft-gont-tcpm-urgent-data-01 . . . . . . . 13 B.7. Changes from draft-ietf-tcpm-urgent-data-00 . . . . . . . 13
B.8. Changes from draft-gont-tcpm-urgent-data-01 . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
This document analyzes how some current TCP implementations process This document analyzes how some current TCP implementations process
TCP urgent indications, and how the behavior of some widely-deployed TCP urgent indications, and how the behavior of some widely-deployed
middle-boxes affect the processing of urgent indications by hosts. middle-boxes affect the processing of urgent indications by hosts.
This document updates RFC 793 [RFC0793], RFC 1011 [RFC1011], and RFC This document updates RFC 793 [RFC0793], RFC 1011 [RFC1011], and RFC
1122 [RFC1122] such that they accommodate current practice in 1122 [RFC1122] such that they accommodate current practice in
processing TCP urgent indications, provides advice to applications processing TCP urgent indications, provides advice to applications
using the urgent mechanism, and raises awareness about the using the urgent mechanism, and raises awareness about the
reliability of TCP urgent indications in the current Internet. reliability of TCP urgent indications in the current Internet.
Given the above issues and potential interoperability issues with
respect to the currently common default mode operation, it is
strongly recommended that applications do not employ urgent
indications. Nevertheless, urgent indications are still retained as
a mandatory part of the TCP protocol to support the few legacy
applications that employ them. However, it is expected that even
these applications will have difficulties in environments with
middle-boxes.
Section 2 describes what the current IETF specifications state with Section 2 describes what the current IETF specifications state with
respect to TCP urgent indications. Section 3 describes how some respect to TCP urgent indications. Section 3 describes how some
current TCP implementations actually process TCP urgent indications. current TCP implementations actually process TCP urgent indications.
Section 4 updates RFC 793 [RFC0793], RFC 1011 [RFC1011], and RFC 1122 Section 4 updates RFC 793 [RFC0793], RFC 1011 [RFC1011], and RFC 1122
[RFC1122], such that they accommodate current practice in processing [RFC1122], such that they accommodate current practice in processing
TCP urgent indications. Section 5 provides advice to to new TCP urgent indications. Section 5 provides advice to to new
applications employing TCP, with respect to the TCP urgent mechanism. applications employing TCP, with respect to the TCP urgent mechanism.
Section 6 provides advice to existing applications that use or rely Section 6 provides advice to existing applications that use or rely
on the TCP urgent mechanism. on the TCP urgent mechanism.
skipping to change at page 4, line 37 skipping to change at page 4, line 46
"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].
2. Specification of the TCP urgent mechanism 2. Specification of the TCP urgent mechanism
2.1. Semantics of urgent indications 2.1. Semantics of urgent indications
TCP incorporates an "urgent mechanism" that allows the sending user TCP incorporates an "urgent mechanism" that allows the sending user
to stimulate the receiving user to accept some "urgent data" and to to stimulate the receiving user to accept some "urgent data" and to
permit the receiving TCP to indicate to the receiving user when all permit the receiving TCP to indicate to the receiving user when all
the currently known urgent data have been received by the user. the currently known urgent data have been received by the receiving
user.
The TCP urgent mechanism permits a point in the data stream to be The TCP urgent mechanism permits a point in the data stream to be
designated as the end of urgent information. Whenever this point is designated as the end of urgent information. Whenever this point is
in advance of the receive sequence number (RCV.NXT) at the receiving in advance of the receive sequence number (RCV.NXT) at the receiving
TCP, that TCP must tell the user to go into "urgent mode"; when the TCP, that TCP must tell the user to go into "urgent mode"; when the
receive sequence number catches up to the urgent pointer, the TCP receive sequence number catches up to the urgent pointer, the TCP
must tell user to go into "normal mode" [RFC0793]. This means, for must tell user to go into "normal mode" [RFC0793]. This means, for
example, that data that was received as "normal data" might become example, that data that was received as "normal data" might become
"urgent data" if an urgent indication is received in some successive "urgent data" if an urgent indication is received in some successive
TCP segment before that data is consumed by the TCP user. TCP segment before that data is consumed by the TCP user.
skipping to change at page 6, line 28 skipping to change at page 6, line 41
when RFC 1122 officially updated RFC 793 to clarify the ambiguity in when RFC 1122 officially updated RFC 793 to clarify the ambiguity in
the semantics of the Urgent Pointer, this clarification was never the semantics of the Urgent Pointer, this clarification was never
reflected into actual implementations (i.e., virtually all reflected into actual implementations (i.e., virtually all
implementations default to the semantics of the urgent pointer implementations default to the semantics of the urgent pointer
specified in Section 3.1 of RFC 793). specified in Section 3.1 of RFC 793).
Some operating systems provide a system-wide toggle to override this Some operating systems provide a system-wide toggle to override this
behavior, and interpret the semantics of the Urgent Pointer as behavior, and interpret the semantics of the Urgent Pointer as
clarified in RFC 1122. However, this system-wide toggle has been clarified in RFC 1122. However, this system-wide toggle has been
found to be inconsistent. For example, Linux provides the sysctl found to be inconsistent. For example, Linux provides the sysctl
"tcp_stdurg" (i.e., net.ivp4.tcp_stdurg) that, when set, supposedly "tcp_stdurg" (i.e., net.ipv4.tcp_stdurg) that, when set, supposedly
changes the system behavior to interpret the semantics of the TCP changes the system behavior to interpret the semantics of the TCP
Urgent Pointer as specified in RFC 1122. However, this sysctl Urgent Pointer as specified in RFC 1122. However, this sysctl
changes the semantics of the Urgent Pointer only for incoming changes the semantics of the Urgent Pointer only for incoming
segments, but not for outgoing segments. This means that if this segments, but not for outgoing segments. This means that if this
sysctl is set, an application might be unable to interoperate with sysctl is set, an application might be unable to interoperate with
itself if both the TCP sender and the TCP receiver are running on the itself if both the TCP sender and the TCP receiver are running on the
same host. same host.
3.3. Allowed length of urgent data 3.3. Allowed length of urgent data
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As a result of the publication of Network Intrusion Detection (NIDs) As a result of the publication of Network Intrusion Detection (NIDs)
evasion techniques based on TCP urgent indications [phrack], some evasion techniques based on TCP urgent indications [phrack], some
middle-boxes clear the urgent indications by clearing the URG flag middle-boxes clear the urgent indications by clearing the URG flag
and setting the Urgent Pointer to zero. This causes the "urgent and setting the Urgent Pointer to zero. This causes the "urgent
data" to become "in line" (that is, accessible by the read(2) call or data" to become "in line" (that is, accessible by the read(2) call or
the recv(2) call without the MSG_OOB flag) in the case of those TCP the recv(2) call without the MSG_OOB flag) in the case of those TCP
implementations that implement the urgent mechanism as out-of-band implementations that implement the urgent mechanism as out-of-band
data (as described in Section 3.1). An example of such a middle-box data (as described in Section 3.1). An example of such a middle-box
is the Cisco PIX firewall [Cisco-PIX]. This should discourage is the Cisco PIX firewall [Cisco-PIX]. This should discourage
applications from depending on urgent indications for their correct applications from depending on urgent indications for their correct
operation, as urgent indications may not be not reliable in the operation, as urgent indications may not be reliable in the current
current Internet. Internet.
4. Updating RFC 793, RFC 1011, and RFC 1122 4. Updating RFC 793, RFC 1011, and RFC 1122
Considering that as long as both the TCP sender and the TCP receiver Considering that as long as both the TCP sender and the TCP receiver
implement the same semantics for the Urgent Pointer there is no implement the same semantics for the Urgent Pointer there is no
functional difference in having the Urgent Pointer point to "the functional difference in having the Urgent Pointer point to "the
sequence number of the octet following the urgent data" vs. "the last sequence number of the octet following the urgent data" vs. "the last
octet of urgent data", and since all known implementations interpret octet of urgent data", and since all known implementations interpret
the semantics of the Urgent Pointer as pointing to "the sequence the semantics of the Urgent Pointer as pointing to "the sequence
number of the octet following the urgent data", we hereby update RFC number of the octet following the urgent data", we hereby update RFC
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However, TCP implementations MUST still include support for the However, TCP implementations MUST still include support for the
urgent mechanism such that existing applications can still use it. urgent mechanism such that existing applications can still use it.
6. Advice to applications that make use of the urgent mechanism 6. Advice to applications that make use of the urgent mechanism
Even though applications SHOULD NOT employ the urgent mechanism, Even though applications SHOULD NOT employ the urgent mechanism,
applications that still decide to employ it MUST set the SO_OOBINLINE applications that still decide to employ it MUST set the SO_OOBINLINE
socket option, such that "urgent data" is delivered inline, as socket option, such that "urgent data" is delivered inline, as
intended by the IETF specifications. intended by the IETF specifications.
Additionally, applications that still decide to use the urgent
mechanism need to be designed for correct operation even when the URG
flag is cleared by middleboxes.
7. Security Considerations 7. Security Considerations
Given that there are two different interpretations of the semantics Multiple factors can affect the data flow that is actually delivered
of the Urgent Pointer in current implementations (e.g., depending on to an application when the TCP urgent mechanism is employed; namely,
the value of the tcp_stdurg sysctl), and that middle-boxes (such as the two possible interpretations of the semantics of the Urgent
packet scrubbers) or the end-systems themselves could cause the Pointer in current implementations (e.g., depending on the value of
urgent data to be processed "in band", there exists ambiguity in how the tcp_stdurg sysctl), the possible implementation of the urgent
"urgent data" sent by a TCP will be processed by the intended mechanism as an Out-Of-Band (OOB) facility (vs. in-band as intenteded
recipient. This might make it difficult for a Network Intrusion by the IETF specifications), and middle-boxes (such as packet
Detection System (NIDS) to track the application-layer data scrubbers) or the end-systems themselves that could cause the "urgent
transferred to the destination system, and thus lead to false data" to be processed "in band". This might make it difficult for a
negatives or false positives in the NIDS [CPNI-TCP]. Network Intrusion Detection System (NIDS) to track the application-
layer data transferred to the destination system, and thus lead to
false negatives or false positives in the NIDS [CPNI-TCP] [phrack].
Probably the best way to avoid the security implications of TCP Probably the best way to avoid the security implications of TCP
urgent data is to avoid having applications use the TCP urgent urgent data is to avoid having applications use the TCP urgent
mechanism altogether. Packet scrubbers could probably be configured mechanism altogether. Packet scrubbers could probably be configured
to clear the URG bit, and set the Urgent Pointer to zero. This would to clear the URG bit, and set the Urgent Pointer to zero. This would
basically cause the urgent data to be put "in band". However, this basically cause the urgent data to be put "in band". However, this
might cause interoperability problems or undesired behavior in the might cause interoperability problems or undesired behavior in those
applications running on top of TCP. applications that rely on the TCP urgent mechanism, such as Telner
[RFC0854] and FTP [RFC0959].
8. IANA Considerations 8. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
9. Acknowledgements 9. Acknowledgements
The authors of this document would like to thank (in alphabetical The authors of this document would like to thank (in alphabetical
order) David Borman, Wesley Eddy, John Heffner, Alfred Hoenes, Carlos order) Jari Arkko, Ron Bonica, David Borman, Dave Cridland, Ralph
Pignataro, Anantha Ramaiah, Joe Touch, Michael Welzl, Dan Wing, and Droms, Wesley Eddy, John Heffner, Alfred Hoenes, Alexey Melnikov,
Alexander Zimmermann for providing valuable feedback on earlier Keith Moore, Carlos Pignataro, Tim Polk, Anantha Ramaiah, Joe Touch,
versions of this document. Michael Welzl, Dan Wing, and Alexander Zimmermann for providing
valuable feedback on earlier versions of this document.
Additionally, Fernando would like to thank David Borman and Joe Touch Additionally, Fernando would like to thank David Borman and Joe Touch
for a fruitful discussion about TCP urgent mode at IETF 73 for a fruitful discussion about TCP urgent mode at IETF 73
(Minneapolis). (Minneapolis).
10. References 10. References
10.1. Normative References 10.1. Normative References
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
skipping to change at page 9, line 40 skipping to change at page 10, line 14
asa70/command/reference/tz.html#wp1288756". asa70/command/reference/tz.html#wp1288756".
[FreeBSD] The FreeBSD project, "http://www.freebsd.org". [FreeBSD] The FreeBSD project, "http://www.freebsd.org".
[Linux] The Linux Project, "http://www.kernel.org". [Linux] The Linux Project, "http://www.kernel.org".
[NetBSD] The NetBSD project, "http://www.netbsd.org". [NetBSD] The NetBSD project, "http://www.netbsd.org".
[OpenBSD] The OpenBSD project, "http://www.openbsd.org". [OpenBSD] The OpenBSD project, "http://www.openbsd.org".
[RFC0854] Postel, J. and J. Reynolds, "Telnet Protocol
Specification", STD 8, RFC 854, May 1983.
[RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985.
[UNPv1] Stevens, W., "UNIX Network Programming, Volume 1. [UNPv1] Stevens, W., "UNIX Network Programming, Volume 1.
Networking APIs: Sockets and XTI", Prentice Hall PTR , Networking APIs: Sockets and XTI", Prentice Hall PTR ,
1997. 1997.
[Windows2000] [Windows2000]
Microsoft Windows 2000, "http://technet.microsoft.com/ Microsoft Windows 2000, "http://technet.microsoft.com/
en-us/library/bb726981(printer).aspx". en-us/library/bb726981(printer).aspx".
[Windows95] [Windows95]
Microsoft Windows 95, Microsoft Windows 95,
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BSDUrgent system-wide variable to override this behavior, BSDUrgent system-wide variable to override this behavior,
interpreting the Urgent Pointer as specified in RFC 1122 [RFC1122]. interpreting the Urgent Pointer as specified in RFC 1122 [RFC1122].
Windows 95 supports only one byte of urgent data. That is, only the Windows 95 supports only one byte of urgent data. That is, only the
byte preceding the Urgent Pointer is considered as "urgent data". byte preceding the Urgent Pointer is considered as "urgent data".
[Windows95] [Windows95]
Appendix B. Changes from previous versions of the draft (to be removed Appendix B. Changes from previous versions of the draft (to be removed
by the RFC Editor before publishing this document as an by the RFC Editor before publishing this document as an
RFC) RFC)
B.1. Changes from draft-ietf-tcpm-urgent-data-05 B.1. Changes from draft-ietf-tcpm-urgent-data-06
o Addresses Jari Arkko's and Tim Polk's DISCUSSes, and various
COMMENTs by members of the IESG.
o Addresses IETF LC comments.
B.2. Changes from draft-ietf-tcpm-urgent-data-05
o Draft resubmitted (with no changes) because it was close to the o Draft resubmitted (with no changes) because it was close to the
expiration day. expiration day.
B.2. Changes from draft-ietf-tcpm-urgent-data-04 B.3. Changes from draft-ietf-tcpm-urgent-data-04
o Fixes grammar errors wrt the term "data" (thanks to David Borman, o Fixes grammar errors wrt the term "data" (thanks to David Borman,
once again ;-) ) once again ;-) )
B.3. Changes from draft-ietf-tcpm-urgent-data-03 B.4. Changes from draft-ietf-tcpm-urgent-data-03
o Addresses feedback sent by David Borman, and nit pointed out by o Addresses feedback sent by David Borman, and nit pointed out by
John Heffner. John Heffner.
B.4. Changes from draft-ietf-tcpm-urgent-data-02 B.5. Changes from draft-ietf-tcpm-urgent-data-02
o Addresses WGLC feedback submitted by Michael Welzl, Anantha o Addresses WGLC feedback submitted by Michael Welzl, Anantha
Ramaiah, and Wesley Eddy. Ramaiah, and Wesley Eddy.
B.5. Changes from draft-ietf-tcpm-urgent-data-01 B.6. Changes from draft-ietf-tcpm-urgent-data-01
o Fixes reference to Cisco IOS Software (layer 8+ stuff ;-) ). o Fixes reference to Cisco IOS Software (layer 8+ stuff ;-) ).
o Cleaned-up Appendix A.5. o Cleaned-up Appendix A.5.
B.6. Changes from draft-ietf-tcpm-urgent-data-00 B.7. Changes from draft-ietf-tcpm-urgent-data-00
o Minor editorial changes. o Minor editorial changes.
o Incorporated the specific changes/advice stated in o Incorporated the specific changes/advice stated in
http://www.ietf.org/mail-archive/web/tcpm/current/msg04548.html in http://www.ietf.org/mail-archive/web/tcpm/current/msg04548.html in
different sections (Section 4, Section 5, Section 6). different sections (Section 4, Section 5, Section 6).
B.7. Changes from draft-gont-tcpm-urgent-data-01 B.8. Changes from draft-gont-tcpm-urgent-data-01
o Draft resubmitted as draft-ietf, as a result of wg consensus on o Draft resubmitted as draft-ietf, as a result of wg consensus on
adopting the document as a tcpm wg item. adopting the document as a tcpm wg item.
Authors' Addresses Authors' Addresses
Fernando Gont Fernando Gont
Universidad Tecnologica Nacional / Facultad Regional Haedo Universidad Tecnologica Nacional / Facultad Regional Haedo
Evaristo Carriego 2644 Evaristo Carriego 2644
Haedo, Provincia de Buenos Aires 1706 Haedo, Provincia de Buenos Aires 1706
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