draft-ietf-mpls-3209-patherr-01.txt   draft-ietf-mpls-3209-patherr-02.txt 
Networking Working Group JP. Vasseur, Ed. Networking Working Group JP. Vasseur, Ed.
Internet-Draft George. Swallow Internet-Draft George. Swallow
Intended status: Best Current Cisco Systems, Inc Intended status: Best Current Cisco Systems, Inc
Practice Adrian. Farrel Practice Ina. Minei
Expires: August 11, 2008 Old Dog Consulting Expires: August 21, 2008 Juniper Networks
Ina. Minei February 18, 2008
Juniper Networks
February 8, 2008
Node behavior upon originating and receiving Resource ReserVation Node behavior upon originating and receiving Resource ReserVation
Protocol (RSVP) Path Error message Protocol (RSVP) Path Error message
draft-ietf-mpls-3209-patherr-01.txt draft-ietf-mpls-3209-patherr-02.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
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 39 skipping to change at page 1, line 37
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."
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.
This Internet-Draft will expire on August 11, 2008. This Internet-Draft will expire on August 21, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
Abstract Abstract
The aim of this document is to describe a common practice with regard The aim of this document is to describe a common practice with regard
to the behavior of a node sending a Resource ReserVation Protocol to the behavior of a node sending a Resource ReserVation Protocol
(RSVP) Traffic Engineering (TE) Path Error message and to the (RSVP) Traffic Engineering (TE) Path Error message and to the
skipping to change at page 2, line 17 skipping to change at page 2, line 15
protocol extensions. protocol extensions.
Requirements Language Requirements Language
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].
Table of Contents Table of Contents
1. Protocol behavior . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Behavior at Detecting Nodes . . . . . . . . . . . . . . . . 4 2. Protocol behavior . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Behavior at Receiving Nodes . . . . . . . . . . . . . . . . 4 2.1. Behavior at Detecting Nodes . . . . . . . . . . . . . . . . 4
1.3. Data Plane Behavior . . . . . . . . . . . . . . . . . . . . 5 2.2. Behavior at Receiving Nodes . . . . . . . . . . . . . . . . 5
2. RSVP PathErr Messages For a Preempted TE LSP . . . . . . . . . 5 2.3. Data Plane Behavior . . . . . . . . . . . . . . . . . . . . 5
3. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 3. RSVP PathErr Messages For a Preempted TE LSP . . . . . . . . . 5
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
5. Normative References . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
7. Normative References . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . . . . 8
1. Protocol behavior 1. Introduction
The aim of this document is to describe a common practice with regard
to the behavior of a node sending a Resource ReserVation Protocol
(RSVP) Traffic Engineering (TE) Path Error message and to the
behavior of a node receiving an RSVP Path Error message for a
preempted Multi-Protocol Label Switching (MPLS) Traffic Engineering
Label Switched Path (TE LSP).
[RFC2205] defines two RSVP error message types: PathErr and ResvErr [RFC2205] defines two RSVP error message types: PathErr and ResvErr
that are generated when an error occurs. Path Error Messages that are generated when an error occurs. Path Error Messages
(PathErr) are used to report errors and travel upstream toward the (PathErr) are used to report errors and travel upstream toward the
head-end of the flow. Resv Error messages (ResvErr) travel head-end of the flow. Resv Error messages (ResvErr) travel
downstream toward the tail-end of the flow. downstream toward the tail-end of the flow.
This document describes only PathErr message processing for the This document describes only PathErr message processing for the
specific case of a preempted Traffic Engineering Label Switched Path specific case of a preempted Traffic Engineering Label Switched Path
(TE LSP) where the term preemption is defined in [RFC3209]. PathErr (TE LSP) where the term preemption is defined in [RFC3209].
messages are routed hop-by-hop using the path state established when
a Path message is routed through the network from the head-end to its 2. Protocol behavior
tail-end.
PathErr messages are routed hop-by-hop using the path state
established when a Path message is routed through the network from
the head-end to its tail-end.
As stated in [RFC2205], PathErr messages do not modify the state of As stated in [RFC2205], PathErr messages do not modify the state of
any node through which they pass; they are only reported to the head- any node through which they pass; they are only reported to the head-
end of the TE LSP (Traffic Engineering Label Switched Path). end of the TE LSP (Traffic Engineering Label Switched Path).
The format of the PathErr message as defined in [RFC2205] is as The format of the PathErr message as defined in [RFC2205] is as
follows: follows:
<PathErr message> ::= <Common Header> [ <INTEGRITY> ] <PathErr message> ::= <Common Header> [ <INTEGRITY> ]
<SESSION> <ERROR_SPEC> <SESSION> <ERROR_SPEC>
skipping to change at page 4, line 27 skipping to change at page 4, line 38
o After a TE LSP has been successfully established. o After a TE LSP has been successfully established.
Nodal behavior is dependent on which combination of the four cases Nodal behavior is dependent on which combination of the four cases
listed above applies. The following sections describe the expected listed above applies. The following sections describe the expected
behavior at nodes that perform a preemption action for a TE LSP (and behavior at nodes that perform a preemption action for a TE LSP (and
therefore report using error PathErr messages), and at nodes that therefore report using error PathErr messages), and at nodes that
receive PathErr messages. This text is a clarification and re- receive PathErr messages. This text is a clarification and re-
statement of the procedures set out in [RFC3209] and does not define statement of the procedures set out in [RFC3209] and does not define
any new behavior. any new behavior.
1.1. Behavior at Detecting Nodes 2.1. Behavior at Detecting Nodes
In the case of fatal errors, the detecting node must send a PathErr In the case of fatal errors, the detecting node must send a PathErr
message reporting the error condition, and must clear the message reporting the error condition, and must clear the
corresponding Path and Resv (control plane) states. A direct corresponding Path and Resv (control plane) states. A direct
implication is that the data plane resources of such a TE LSP are implication is that the data plane resources of such a TE LSP are
also released, thus resulting in traffic disruption. It should be also released, thus resulting in traffic disruption. It should be
noted, however, that in fatal error cases, the LSP has usually noted, however, that in fatal error cases, the LSP has usually
already failed in the data plane, and traffic has already been already failed in the data plane, and traffic has already been
disrupted. When the error arises during LSP establishment, the disrupted. When the error arises during LSP establishment, the
implications are different to when it arises on an active LSP since implications are different to when it arises on an active LSP since
no traffic flows until the LSP has been fully established. In the no traffic flows until the LSP has been fully established. In the
case of non-fatal errors, the detecting node should send a PathErr case of non-fatal errors, the detecting node should send a PathErr
message, and must not clear control plane or data plane state. message, and must not clear control plane or data plane state.
1.2. Behavior at Receiving Nodes 2.2. Behavior at Receiving Nodes
Nodes that receive PathErr messages are all of the nodes along the Nodes that receive PathErr messages are all of the nodes along the
path of the TE LSP upstream of the node that detected the error. path of the TE LSP upstream of the node that detected the error.
This includes the head-end node. In accordance with [RFC2205] a node This includes the head-end node. In accordance with [RFC2205] a node
receiving a PathErr message takes no action upon it and consequently receiving a PathErr message takes no action upon it and consequently
it must not clear Path or Resv control plane or data plane state. it must not clear Path or Resv control plane or data plane state.
This is true regardless of whether the error condition reported by This is true regardless of whether the error condition reported by
the PathErr is fatal or non-fatal. RSVP states should only be the PathErr is fatal or non-fatal. RSVP states should only be
affected upon receiving a PathTear or ResvTear message, or in the affected upon receiving a PathTear or ResvTear message, or in the
event of a Path or Resv state timeout. Further discussion of the event of a Path or Resv state timeout. Further discussion of the
processing of these events is outside the scope of this document. processing of these events is outside the scope of this document.
Note that [RFC3473] defines a Path_State_Removed flag in the Note that [RFC3473] defines a Path_State_Removed flag in the
ERROR_SPEC object carried on a PathErr message. This field may be ERROR_SPEC object carried on a PathErr message. This field may be
set to change the behavior of upstream nodes that receive the PathErr set to change the behavior of upstream nodes that receive the PathErr
message. When set, the flag indicates that the message sender has message. When set, the flag indicates that the message sender has
removed Path state (and any associated Resv and data plane state) for removed Path state (and any associated Resv and data plane state) for
the TE LSP. The message receiver should do likewise before the TE LSP. The message receiver should do likewise before
forwarding the message, but may retain state and clear the flag forwarding the message, but may retain state and clear the flag
before forwarding the message. before forwarding the message.
1.3. Data Plane Behavior 2.3. Data Plane Behavior
Any node clearing either or both the Path or the Resv state of a TE Any node clearing either or both the Path or the Resv state of a TE
LSP MUST also free up the data plane resources allocated to the LSP MUST also free up the data plane resources allocated to the
corresponding TE LSP. corresponding TE LSP.
2. RSVP PathErr Messages For a Preempted TE LSP 3. RSVP PathErr Messages For a Preempted TE LSP
Two Error-code can be used to report a preempted TE LSPs: Two Error-code can be used to report a preempted TE LSPs:
o As defined in [RFC2750]:Error Code=2: "Policy Control Failure", o As defined in [RFC2750]:Error Code=2: "Policy Control Failure",
Error Value=5 "Flow was preempted" Error Value=5 "Flow was preempted"
o As defined in [RFC2205], Error Code=12: "Service preempted" o As defined in [RFC2205], Error Code=12: "Service preempted"
In both cases, these are fatal errors. In both cases, these are fatal errors.
3. Security Considerations 4. IANA Considerations
This document does not define any new protocol extensions and thus no
action is requested to IANA.
5. Security Considerations
This document does not define any new procedures, but clarifies those This document does not define any new procedures, but clarifies those
defined in other documents where security considerations are already defined in other documents where security considerations are already
specified. This document does not raise specific security issues specified. This document does not raise specific security issues
beyond those of existing MPLS-TE. By clarifying the procedures, this beyond those of existing MPLS-TE. By clarifying the procedures, this
document reduces the security risk introduced by non-conformant document reduces the security risk introduced by non-conformant
implementations. implementations.
4. Acknowledgements 6. Acknowledgements
The author would like to thank Carol Iturralde, Ashok Narayanan, Rom The author would like to thank Carol Iturralde, Ashok Narayanan, Rom
Reuther and Reshad Rahman. Reuther and Reshad Rahman.
5. Normative References 7. 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, March 1997.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997. Functional Specification", RFC 2205, September 1997.
[RFC2750] Herzog, S., "RSVP Extensions for Policy Control", [RFC2750] Herzog, S., "RSVP Extensions for Policy Control",
RFC 2750, January 2000. RFC 2750, January 2000.
skipping to change at page 6, line 34 skipping to change at page 7, line 4
Authors' Addresses Authors' Addresses
JP Vasseur (editor) JP Vasseur (editor)
Cisco Systems, Inc Cisco Systems, Inc
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: jpv@cisco.com Email: jpv@cisco.com
George Swallow George Swallow
Cisco Systems, Inc Cisco Systems, Inc
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: swallow@cisco.com Email: swallow@cisco.com
Adrian Farrel
Old Dog Consulting
Email: adrian@olddog.co.uk
Ina Minei Ina Minei
Juniper Networks Juniper Networks
1194 North Mathilda Ave. 1194 North Mathilda Ave.
Sunnyvale, 94089 Sunnyvale, 94089
Email: ina@juniper.net Email: ina@juniper.net
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
 End of changes. 15 change blocks. 
32 lines changed or deleted 42 lines changed or added

This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/