--- 1/draft-ietf-ccamp-gmpls-recovery-terminology-04.txt 2006-02-04 22:56:23.000000000 +0100 +++ 2/draft-ietf-ccamp-gmpls-recovery-terminology-05.txt 2006-02-04 22:56:23.000000000 +0100 @@ -1,53 +1,60 @@ + CCAMP Working Group CCAMP GMPLS P&R Design Team Internet Draft -Category: Standards Track Eric Mannie (Editor) -Expiration Date: October 2004 Dimitri Papadimitriou (Editor) +Category: Informational Eric Mannie (Editor) +Expiration Date: March 2005 Dimitri Papadimitriou (Editor) - April 2004 + October 2004 Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching (GMPLS) - draft-ietf-ccamp-gmpls-recovery-terminology-04.txt + draft-ietf-ccamp-gmpls-recovery-terminology-05.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions - of Section 10 of RFC2026. + of section 3 of RFC 3667. By submitting this Internet-Draft, each + author represents that any applicable patent or other IPR claims of + which he or she is aware have been or will be disclosed, and any of + which he or she become aware will be disclosed, in accordance with + RFC 3668. Internet-Drafts are working documents of the Internet Engineering - Task Force (IETF), its areas, and its working groups. Note that other - groups may also distribute working documents as Internet-Drafts. + Task Force (IETF), its areas, and its working groups. Note that + other groups may also distribute working documents as Internet- + Drafts. - Internet-Drafts are draft documents valid for a maximum of six months - and may be updated, replaced, or obsoleted by other documents at any - time. It is inappropriate to use Internet-Drafts as reference + Internet-Drafts are draft documents valid for a maximum of six + months and may be updated, replaced, or obsoleted by other documents + at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at - http://www.ietf.org/1id-abstracts.html. + http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - For potential updates to the above required-text see: - http://www.ietf.org/ietf/1id-guidelines.txt +Copyright Notice + + Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document defines a common terminology for Generalized Multi- Protocol Label Switching (GMPLS) based recovery mechanisms (i.e. protection and restoration). The terminology is independent of the underlying transport technologies covered by GMPLS. -E.Mannie, D.Papadimitriou et al. - Standards Track 1 +E.Mannie, D.Papadimitriou et al. - Informational 1 Table of Contents Status of this Memo .............................................. 1 Abstract ......................................................... 1 Table of Contents ................................................ 2 1. Contributors .................................................. 3 2. Introduction .................................................. 3 3. Conventions used in this document ............................. 4 4. Recovery Terminology Common to Protection and Restoration ..... 4 @@ -61,54 +68,55 @@ 4.8 Selector Types ............................................... 9 4.9 Recovery GMPLS Nodes ........................................ 10 4.10 Switch-over Mechanism ...................................... 10 4.11 Reversion operations ....................................... 10 4.12 Failure Reporting .......................................... 11 4.13 External commands .......................................... 11 4.14 Unidirectional versus Bi-Directional Recovery Switching .... 12 4.15 Full versus Partial Span Recovery Switching ................ 12 4.16 Recovery Schemes Related Time and Durations ................ 13 4.17 Impairment ................................................. 13 - 4.18 Recovery Ratio ............................................. 13 + 4.18 Recovery Ratio ............................................. 14 4.19 Hitless Protection Switch-over ............................. 14 4.20 Network Survivability ...................................... 14 4.21 Survivable Network ......................................... 14 4.22 Escalation ................................................. 14 5. Recovery Phases .............................................. 14 5.1 Entities Involved During Recovery ........................... 15 6. Protection Schemes ........................................... 16 6.1 1+1 Protection .............................................. 16 6.2 1:N (N >= 1) Protection ..................................... 16 6.3 M:N (M, N > 1, N >= M) Protection ........................... 16 6.4 Notes on Protection Schemes ................................. 16 7. Restoration Schemes .......................................... 17 7.1 Pre-planned LSP Restoration ................................. 17 7.1.1 Shared-Mesh Restoration ................................... 17 - 7.2 LSP Restoration ............................................. 17 + 7.2 LSP Restoration ............................................. 18 7.2.1 Hard LSP Restoration ...................................... 18 7.2.2 Soft LSP Restoration ...................................... 18 8. Security Considerations ...................................... 18 - 9. Intellectual Property Consideration .......................... 18 - 9.1 IPR Disclosure Acknowledgement .............................. 18 - 10. References .................................................. 19 - 10.1 Normative References ....................................... 19 - 10.2 Informative References ..................................... 19 - 11. Acknowledgments ............................................. 20 - 12. Editor's Addresses .......................................... 20 + 9. References ................................................... 18 + 9.1 Normative References ........................................ 18 + 9.2 Informative References ...................................... 18 + 10. Acknowledgments ............................................. 19 + 11. Editor's Address ............................................ 19 + Intellectual Property Statement ................................. 20 + Disclaimer of Validity .......................................... 20 -E.Mannie, D.Papadimitriou et al.- Standards Track 2 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 2 + Copyright Statement ............................................. 20 1. Contributors This document is the result of the CCAMP Working Group Protection and Restoration design team joint effort. The following are the - authors that contributed to the present memo: + authors that contributed to the present document: Deborah Brungard (AT&T) Rm. D1-3C22 - 200 S. Laurel Ave. Middletown, NJ 07748, USA EMail: dbrungard@att.com Sudheer Dharanikota EMail: sudheer@ieee.org Jonathan P. Lang (Rincon Networks) @@ -141,30 +149,30 @@ Protocol Label Switching (GMPLS) based recovery mechanisms (i.e. protection and restoration) that are under consideration by the CCAMP Working Group. The terminology proposed in this document is independent of the underlying transport technologies and borrows from the G.808.1 ITU-T Recommendation [G.808.1] and from the G.841 ITU-T Recommendation [G.841]. The restoration terminology and concepts have been gathered from numerous sources including IETF drafts. -E.Mannie, D.Papadimitriou et al.- Standards Track 3 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 3 In the context of this document, the term "recovery" denotes both protection and restoration. The specific terms "protection" and "restoration" will only be used when differentiation is required. - Note that this document focuses on the terminology for the recovery - of LSPs controlled by a GMPLS control plane. We focus on end-to-end, - segment, and span (i.e. link) Label Switched Path (LSP) recovery. - Terminology for control plane recovery is not in the scope of this - document. + This document focuses on the terminology for the recovery of Label + Switched Paths (LSPs) controlled by a GMPLS control plane. The + proposed terminology applies to end-to-end, segment, and span (i.e. + link) recovery. Note that the terminology for recovery of the + control plane itself is not in the scope of this document. Protection and restoration of switched LSPs under tight time constraints is a challenging problem. This is particularly relevant to optical networks that consist of Time Division Multiplex (TDM) and/or all-optical (photonic) cross-connects referred to as GMPLS nodes (or simply nodes, or even sometimes "Label Switching Routers, or LSRs") connected in a general topology [GMPLS-ARCH]. Recovery typically involves the activation of a recovery (or alternate) LSP when a failure is encountered in the working (or @@ -194,21 +202,21 @@ This section defines the following general terms common to both protection and restoration (i.e. recovery). In addition, most of these terms apply to end-to-end, segment and span LSP recovery. Note that span recovery does not protect the nodes at each end of the span, otherwise end-to-end or segment LSP recovery should be used. The terminology and the definitions have been originally taken from [G.808.1]. However, for generalization, the following language that -E.Mannie, D.Papadimitriou et al.- Standards Track 4 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 4 is not directly related to recovery has been adapted to GMPLS and the common IETF terminology: An LSP is used as a generic term to designate either an SNC (Sub- Network Connection) or an NC (Network Connection) in ITU-T terminology. The ITU-T uses the term transport entity to designate either a link, an SNC or an NC. The term "Traffic" is used instead of "Traffic Signal". The term protection or restoration "scheme" is used instead of protection or restoration "architecture". @@ -248,21 +256,21 @@ terminated at the ends of the LSPs/spans that it uses. C. Null traffic: Traffic carried over the recovery LSP/span if it is not used to carry normal or extra traffic. Null traffic can be any kind of traffic that conforms to the signal structure of the specific layer, and it is ignored (not selected) at the egress of the recovery LSP/span. -E.Mannie, D.Papadimitriou et al.- Standards Track 5 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 5 4.3 LSP/Span Protection and Restoration The following subtle distinction is generally made between the terms "protection" and "restoration", even though these terms are often used interchangeably [RFC3386]. The distinction between protection and restoration is made based on the resource allocation done during the recovery LSP/span establishment. The distinction between different types of @@ -302,21 +310,21 @@ Both protection and restoration require signaling. Signaling to establish the recovery resources and signaling associated with the use of the recovery LSP(s)/span(s) are needed. 4.4 Recovery Scope Recovery can be applied at various levels throughout the network. An LSP may be subject to local (span), segment, and/or end-to-end recovery. -E.Mannie, D.Papadimitriou et al.- Standards Track 6 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 6 Local (span) recovery refers to the recovery of an LSP over a link between two nodes. End-to-end recovery refers to the recovery of an entire LSP from its source (ingress node end-point) to its destination (egress node end- point). Segment recovery refers to the recovery over a portion of the network of a segment LSP (i.e. an SNC in the ITU-T terminology) of an end-to-end LSP. Such recovery protects against span and/or node @@ -355,21 +363,21 @@ restoration. B. 0:1 type: unprotected No specific recovery LSP/span protects the working LSP/span. However, the working LSP/span can potentially be restored through any alternate available route/span, with or without any pre-computed restoration route. Note that there are no resources pre-established for this recovery type. -E.Mannie, D.Papadimitriou et al.- Standards Track 7 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 7 This type is applicable to LSP/span restoration, but not to LSP/span protection. Span restoration can be for instance achieved by moving all the LSPs transported over of a failed span to a dynamically selected span. C. 1:1 type: dedicated recovery with extra traffic One specific recovery LSP/span protects exactly one specific working LSP/span but the normal traffic is transmitted only over one LSP (working or recovery) at a time. Extra traffic can be transported @@ -408,21 +416,21 @@ specific working LSPs/spans. The two sets are explicitly identified. Extra traffic can be transported over the M recovery LSPs/spans when available. All the LSPs/spans must start and end at the same nodes. Sometimes, the working LSPs/spans are assumed to be resource disjoint in the network so that they do not share any failure probability, but this is not mandatory. Obviously, if several working LSPs/spans in the set of N are concurrently affected by some failure(s), the traffic on only M of these failed LSPs/spans may be -E.Mannie, D.Papadimitriou et al.- Standards Track 8 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 8 recovered. Note that N can be arbitrarily large (i.e. infinite). The choice of N and M is a policy decision. This type is applicable to LSP/span protection and LSP restoration, but not to span restoration. 4.7 Bridge Types A bridge is the function that connects the normal traffic and extra traffic to the working and recovery LSP/span. @@ -459,21 +467,21 @@ Is a selector that extracts the normal traffic from either the working LSP/span output or the recovery LSP/span output. B. Merging selector For 1:N and M:N protection types, the selector permanently extracts the normal traffic from both the working and recovery LSP/span outputs. This alternative works only in combination with a selector bridge. -E.Mannie, D.Papadimitriou et al.- Standards Track 9 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 9 4.9 Recovery GMPLS Nodes This section defines the GMPLS nodes involved during recovery. A. Ingress GMPLS node of an end-to-end LSP/segment LSP/span The ingress node of an end-to-end LSP/segment LSP/span is where the normal traffic may be bridged to the recovery end-to-end LSP/segment LSP/span. Also known as source node in the ITU-T terminology. @@ -513,21 +521,21 @@ A revertive recovery operation refers to a recovery switching operation, where the traffic returns to (or remains on) the working LSP/span if the switch-over requests are terminated; i.e. when the working LSP/span has recovered from the failure. Therefore a non-revertive recovery switching operation is when the traffic does not return to the working LSP/span if the switch-over requests are terminated. -E.Mannie, D.Papadimitriou et al.- Standards Track 10 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 10 4.12 Failure Reporting This section gives (for information) several signal types commonly used in transport planes to report a failure condition. Note that fault reporting may require additional signaling mechanisms. A. Signal Degrade (SD): a signal indicating that the associated data has degraded. @@ -568,21 +576,21 @@ state. D. Forced switch-over for normal traffic: A switch-over action initiated externally that switches normal traffic to the recovery LSP/span, unless an equal or higher priority switch-over command is in effect. E. Manual switch-over for normal traffic: -E.Mannie, D.Papadimitriou et al.- Standards Track 11 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 11 A switch-over action initiated externally that switches normal traffic to the recovery LSP/span, unless a fault condition exists on other LSPs/spans (including the recovery LSP/span) or an equal or higher priority switch-over command is in effect. F. Manual switch-over for recovery LSP/span: A switch-over action initiated externally that switches normal traffic to the working LSP/span, unless a fault condition exists on the working LSP/span or an equal or higher priority switch-over @@ -621,21 +629,21 @@ is greater than 1 one refers to partial span recovery. A. Full Span Recovery All the S LSP carried over a given span are recovered under span failure condition. Full span recovery is also referred to as "bulk recovery". B. Partial Span Recovery -E.Mannie, D.Papadimitriou et al.- Standards Track 12 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 12 Only a subset s of the S LSP carried over a given span are recovered under span failure condition. Both selection criteria of the entities belonging to this subset and the decision concerning the recovery of the remaining (S - s) LSP are based on local policy. 4.16 Recovery Schemes Related Time and Durations This section gives several typical timing definitions that are of importance for recovery schemes. @@ -674,21 +682,21 @@ LSP/span can be used again to transport the normal traffic and/or to select the normal traffic from. Note: the hold-off time is defined as the time between the reporting of signal fail or degrade, and the initialization of the recovery switching operation. This is useful when multiple layers of recovery are being used. 4.17 Impairment -E.Mannie, D.Papadimitriou et al.- Standards Track 13 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 13 A defect or performance degradation, which may lead to SF or SD trigger. 4.18 Recovery Ratio The quotient of the actually recovery bandwidth divided by the traffic bandwidth which is intended to be protected. 4.19 Hitless Protection Switch-over @@ -727,21 +735,21 @@ with the transport plane). Thus, failure detection (that should occur at the transport layer closest to the failure) is the only phase that can not be achieved by the control plane alone. - Phase 2: Failure Localization (and Isolation) Failure localization provides to the deciding entity information about the location (and so the identity) of the transport plane entity that causes the LSP(s)/span(s) failure. The deciding entity -E.Mannie, D.Papadimitriou et al.- Standards Track 14 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 14 can then take accurate decision to achieve finer grained recovery switching action(s). - Phase 3: Failure Notification Failure notification phase is used 1) to inform intermediate nodes that LSP(s)/span(s) failure has occurred and has been detected 2) to inform the recovery deciding entities (which can correspond to any intermediate or end-point of the failed LSP/span) that the corresponding LSP/span is not available. @@ -779,21 +787,21 @@ An entity that makes the recovery decision or selects the recovery resources. This entity communicates the decision to the impacted LSPs/spans with the recovery actions to be performed. D. Recovering Entity (part of the failure recovery activation process): An entity that participates in the recovery of the LSPs/spans. -E.Mannie, D.Papadimitriou et al.- Standards Track 15 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 15 The process of moving failed LSPs from a failed (working) span to a protection span must be initiated by one of the nodes terminating the span, e.g. A or B. The deciding (and recovering) entity is referred to as the "master" while the other node is called the "slave" and corresponds to a recovering only entity. Note: The determination of the master and the slave may be based on configured information or protocol specific requirements. 6. Protection Schemes @@ -833,21 +841,21 @@ M:N protection has N working LSPs/spans carrying normal traffic and M protection LSP/span that may carry extra-traffic. At the ingress, the normal traffic is either permanently connected to its working LSP/span and may be connected to one of the protection LSPs/spans (case of broadcast bridge), or is connected to either its working or one of the protection LSPs/spans (case of selector bridge). At the egress node, the normal traffic is selected from either its working or one of the protection LSP/span. -E.Mannie, D.Papadimitriou et al.- Standards Track 16 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 16 Unprotected extra traffic can be transported over the M protection LSP/span whenever the protection LSPs/spans is not used to carry a normal traffic. 6.4 Notes on Protection Schemes All protection types are either uni- or bi-directional, obviously, the latter applies only to bi-directional LSP/span and requires coordination between the ingress and egress node during protection switching. @@ -885,21 +893,21 @@ Note: when each working LSP is recoverable by exactly one restoration LSP, one refers also to 1:1 (pre-planned) re-routing without extra-traffic. 7.1.1 Shared-Mesh Restoration "Shared-mesh" restoration is defined as a particular case of pre- planned LSP re-routing that reduces the restoration resource requirements by allowing multiple restoration LSPs (initiated from -E.Mannie, D.Papadimitriou et al.- Standards Track 17 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 17 distinct ingress nodes) to share common resources (including links and nodes.) 7.2 LSP Restoration Also referred to as LSP re-routing. The ingress node switches the normal traffic to an alternate LSP signaled and fully established (i.e. cross-connected) after failure detection and/or notification. The alternate LSP path may be computed after failure detection and/or notification. In this case, one also refers to "Full LSP Re- @@ -919,122 +927,130 @@ Also referred to as soft LSP re-routing. A re-routing operation where the LSP is released after the full establishment of an alternate LSP (i.e. make-before-break). 8. Security Considerations This document does not introduce or imply any specific security consideration. -9. Intellectual Property Consideration +9. References - The IETF takes no position regarding the validity or scope of any - Intellectual Property Rights or other rights that might be claimed - to pertain to the implementation or use of the technology - described in this document or the extent to which any license - under such rights might or might not be available; nor does it - represent that it has made any independent effort to identify any - such rights. Information on the procedures with respect to rights - in RFC documents can be found in BCP 78 and BCP 79. +9.1 Normative References - Copies of IPR disclosures made to the IETF Secretariat and any - assurances of licenses to be made available, or the result of an - attempt made to obtain a general license or permission for the use - of such proprietary rights by implementers or users of this - specification can be obtained from the IETF on-line IPR repository - at http://www.ietf.org/ipr. + [RFC2026] S.Bradner, "The Internet Standards Process -- Revision + 3", BCP 9, RFC 2026, October 1996. -E.Mannie, D.Papadimitriou et al.- Standards Track 18 - The IETF invites any interested party to bring to its attention - any copyrights, patents or patent applications, or other - proprietary rights that may cover technology that may be required - to implement this standard. Please address the information to the - IETF at ietf-ipr@ietf.org. + [RFC2119] S.Bradner, "Key words for use in RFCs to Indicate + Requirement Levels," BCP 14, RFC 2119, March 1997. -9.1 IPR Disclosure Acknowledgement + [RFC3667] S.Bradner, "IETF Rights in Contributions", BCP 78, + RFC 3667, February 2004. - By submitting this Internet-Draft, I certify that any applicable - patent or other IPR claims of which I am aware have been - disclosed, and any of which I become aware will be disclosed, in - accordance with RFC 3668. + [RFC3668] S.Bradner, Ed., "Intellectual Property Rights in IETF + Technology", BCP 79, RFC 3668, February 2004. -10. References +9.2 Informative References -10.1 Normative References +E.Mannie, D.Papadimitriou et al.- Expires March 2005 18 + [GMPLS-ARCH] E.Mannie (Editor), "Generalized MPLS Architecture," + Internet Draft, Work in progress, draft-ietf-ccamp- + gmpls-architecture-07.txt, May 2003. - [RFC2026] S.Bradner, "The Internet Standards Process -- Revision - 3", BCP 9, RFC 2026, October 1996. + [RFC3386] W.S.Lai, et al., "Network Hierarchy and Multilayer + Survivability," RFC 3386, November 2002. - [RFC2119] S.Bradner, "Key words for use in RFCs to Indicate - Requirement Levels," BCP 14, RFC 2119, March 1997. + [T1.105] ANSI, "Synchronous Optical Network (SONET): Basic + Description Including Multiplex Structure, Rates, and + Formats," ANSI T1.105, January 2001. -10.2 Informative References + For information on the availability of the following documents, + please see http://www.itu.int [G.707] ITU-T, "Network Node Interface for the Synchronous Digital Hierarchy (SDH)," Recommendation G.707, October 2000. [G.783] ITU-T, "Characteristics of Synchronous Digital Hierarchy (SDH) Equipment Functional Blocks," Recommendation G.783, October 2000. - [G.806] ITU-T, "Characteristics of Transport Equipment ¡ + [G.806] ITU-T, "Characteristics of Transport Equipment û Description Methodology and Generic Functionality," Recommendation G.806, October 2000. - [G.808.1] ITU-T, "Generic Protection Switching ¡ Linear trail and + [G.808.1] ITU-T, "Generic Protection Switching û Linear trail and subnetwork protection," Recommendation G.808.1, December 2003. [G.841] ITU-T, "Types and Characteristics of SDH Network Protection Architectures," Recommendation G.841, October 1998. [G.842] ITU-T, "Interworking of SDH network protection architectures," Recommendation G.842, October 1998. - [GMPLS-ARCH] E.Mannie (Editor), "Generalized MPLS Architecture," - Internet Draft, Work in progress, draft-ietf-ccamp- - gmpls-architecture-07.txt, May 2003. - -E.Mannie, D.Papadimitriou et al.- Standards Track 19 - [RFC3386] W.S.Lai, et al., "Network Hierarchy and Multilayer - Survivability," RFC 3386, November 2002. - - [T1.105] ANSI, "Synchronous Optical Network (SONET): Basic - Description Including Multiplex Structure, Rates, and - Formats," ANSI T1.105, January 2001. - -11. Acknowledgments +10. Acknowledgments Many thanks to Adrian Farrel for having thoroughly review this document. -12. Editor's Addresses +11. Editor's Addresses Eric Mannie EMail: eric_mannie@hotmail.com Dimitri Papadimitriou (Alcatel) Francis Wellesplein, 1 B-2018 Antwerpen, Belgium Phone: +32 3 240-8491 EMail: dimitri.papadimitriou@alcatel.be -E.Mannie, D.Papadimitriou et al.- Standards Track 20 +E.Mannie, D.Papadimitriou et al.- Expires March 2005 19 -Full Copyright Statement +Intellectual Property Statement - Copyright (C) The Internet Society (2004). This document is subject - to the rights, licenses and restrictions contained in BCP 78 and - except as set forth therein, the authors retain all their rights. + The IETF takes no position regarding the validity or scope of any + Intellectual Property Rights or other rights that might be claimed + to pertain to the implementation or use of the technology described + in this document or the extent to which any license under such + rights might or might not be available; nor does it represent that + it has made any independent effort to identify any such rights. + Information on the procedures with respect to rights in RFC + documents can be found in BCP 78 and BCP 79. + + Copies of IPR disclosures made to the IETF Secretariat and any + assurances of licenses to be made available, or the result of an + attempt made to obtain a general license or permission for the use + of such proprietary rights by implementers or users of this + specification can be obtained from the IETF on-line IPR repository + at http://www.ietf.org/ipr. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights that may cover technology that may be required to implement + this standard. Please address the information to the IETF at + ietf-ipr@ietf.org. + +Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. -E.Mannie, D.Papadimitriou et al.- Standards Track 21 +Copyright Statement + + Copyright (C) The Internet Society (2004). This document is subject + to the rights, licenses and restrictions contained in BCP 78, and + except as set forth therein, the authors retain all their rights. + +Acknowledgment + + Funding for the RFC Editor function is currently provided by the + Internet Society. + +E.Mannie, D.Papadimitriou et al.- Expires March 2005 20