MPLS Working Group M. Vigoureux Internet Draft M. Bocci Updates: 3032, 4385 Alcatel-Lucent Intended status: Standard Track Expires: May 2009 G. Swallow D. Ward Cisco Systems, Inc. R. Aggarwal Juniper Networks November 27, 2008 MPLS Generic Associated Channel draft-ietf-mpls-tp-gach-gal-00 Status of this Memo 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 becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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. 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/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on April 27, 2009. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract Bocci et al. Expires May 27, 2009 [Page 1]
Internet-Draft G-ACH and GAL November 2008 This document generalises the applicability of the pseudowire Associated Channel Header (ACH), enabling the realization of a control channel associated to MPLS Label Switched Paths (LSP), MPLS pseudowires (PW) and MPLS Sections. In order to identify the presence of this G-ACH, this document also assigns of one of the reserved MPLS label values to the 'Generic Alert Label (GAL)', to be used as a label based exception mechanism. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1]. Table of Contents 1. Introduction................................................3 1.1. Contributing Authors....................................4 1.2. Objectives.............................................4 1.3. Scope..................................................4 1.4. Terminology............................................5 2. Generic Associated Channel...................................5 2.1. Allocation of Channel Types.............................6 3. Generalised Exception Mechanism..............................6 3.1. Relationship with Existing MPLS OAM Alert Mechanisms.....6 3.2. GAL Applicability and Usage.............................7 3.2.1. GAL Processing.....................................7 3.2.1.1. MPLS Section..................................7 3.2.1.2. Label Switched Paths..........................8 3.2.1.3. Tandem Connection Monitoring Entity...........9 3.3. Relationship with RFC 3429.............................10 4. Compatibility..............................................10 5. Congestion Considerations...................................10 6. Security Considerations.....................................11 7. IANA Considerations........................................11 8. Acknowledgments............................................12 9. References.................................................12 9.1. Normative References...................................12 9.2. Informative References.................................13 Authors' Addresses............................................14 Contributing Authors' Addresses................................14 Intellectual Property Statement................................15 Disclaimer of Validity........................................15 Bocci et al. Expires May 27, 2009 [Page 2]
Internet-Draft G-ACH and GAL November 2008 1. Introduction There is a need for Operations, Administration and Maintenance (OAM) mechanisms that can be used for edge-to-edge (i.e. between originating and terminating LSRs or T-PEs) and segment fault detection (e.g. between any two LSRs or T-PEs/S-PEs along the path of an LSP or PW or an MPLS section [17]), diagnostics, maintenance and other functions for a Pseudowire and an LSP. Some of these functions can be supported using tools such as VCCV [8], BFD [9], or LSP-Ping [6]. However, a requirement has been indicated to extend these toolsets, in particular where MPLS networks are used for packet transport services and network operations [16]. These include performance monitoring, automatic protection switching, and support for management and signaling communication channels. These tools must be applicable to, and function in essentially the same manner (from an operational point of view) on both MPLS PWs and MPLS LSPs. They must also operate in-band on the PW or LSP such that they do not depend on PSN routing, user data traffic or ultimately on control plane functions. Virtual Circuit Connectivity Verification (VCCV) can use an associated channel to provide a control channel between a PW's ingress and egress points over which OAM and other control messages can be exchanged. In this document, we propose a generic associated channel header (G-ACH) to enable the same control channel mechanism be used for MPLS Sections, LSPs and PWs. The associated channel header (ACH) specified in RFC 4385 [11] is used with additional code points to support additional MPLS OAM functions. Generalizing the ACH mechanism to MPLS LSPs and MPLS Sections also requires a method to identify that a packet contains a G-ACH followed by a non-service payload. This document therefore also defines a label based exception mechanism (the Generic Alert Label, or GAL) that serves to inform an LSR that a packet that it receives on an LSP or section belongs to an associated channel. RFC 4379 [6] and BFD for MPLS LSPs [9] have defined alert mechanisms that enable a MPLS LSR to identify and process MPLS OAM packets when the OAM packets are encapsulated in an IP header. These alert mechanisms are based on TTL expiration and/or use an IP destination address in the range 127/8. These mechanisms are the default mechanisms for identifying MPLS OAM packets when the OAM packets are encapsulated in an IP header. However it may not always be possible to use these mechanisms in some MPLS applications, (e.g. MPLS-TP [17]) particularly when IP based demultiplexing cannot be used. This document proposes an OPTIONAL mechanism that is RECOMMENDED for Bocci et al. Expires May 27, 2009 [Page 3]
Internet-Draft G-ACH and GAL November 2008 identifying and demultiplexing MPLS OAM packets when IP based mechanisms such as [6] and [9] are not available. The G-ACH and GAL mechanisms are defined to work together. Note that, in this document, OAM functions and packets should be understood in the broad sense, that is, as a set of FCAPS mechanisms that also include Automatic Protection Switching (APS), Signalling Control Channel (SCC) and Management Control Channel (MCC). Note that the GAL and G-ACH are applicable to MPLS in general. Their applicability to specific applications is outside the scope of this document. For example, the applicability of the GAL and G-ACH to MPLS-TP is described in [17] and [18]. 1.1. Contributing Authors The editors gratefully acknowledge the following additional contributors: Stewart Bryant, Italo Busi, Marc Lasserre, Lieven Levrau, and Lou Berger. 1.2. Objectives This document proposes a mechanism to provide for the extended OAM needs of emerging applications for MPLS. It creates a generic OAM identification mechanism that may be applied to all MPLS LSPs, while maintaining compatibility with the PW associated channel header (ACH) [11]. It also normalizes the use of the ACH for PWs in a transport context. 1.3. Scope This document defines the encapsulation header for LSP, MPLS Section and PW associated channel messages. It does not define how associated channel capabilities are signaled or negotiated between LSRs or PEs, the operation of various OAM functions, or the messages transmitted on the associated channel. This document does not deprecate existing MPLS and PW OAM mechanisms. Bocci et al. Expires May 27, 2009 [Page 4]
Internet-Draft G-ACH and GAL November 2008 1.4. Terminology G-ACH: Generic Associated Channel Header GAL: Generic Alert Label 2. Generic Associated Channel VCCV [8] defines three Control Channel Types that may be used to multiplex OAM messages onto a PW: CC Type 1 uses an associated channel header and is referred to as "In-band VCCV"; CC Type 2 uses the router alert label to indicate VCCV packets and is referred to as "Out of Band VCCV"; CC Type 3 uses the TTL to force the packet to be processed by the targeted routers control plane and is referred to as "MPLS PW Label with TTL == 1". The use of the CC Type 1, currently limited to MPLS PWs, is extended to apply to MPLS LSPs as well as to MPLS Sections. This associated channel header is called the Generic Associated Channel Header (G- ACH). The CC Type 1 channel header is depicted in figure below: 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 0 0 1|Version| Reserved | Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 : Generic Associated Channel Header In the above figure, the first nibble is set to 0001b to indicate a channel associated with a PW, a LSP or a Section. The Version and Reserved fields are set to 0, as specified in RFC 4385 [11]. Note that VCCV also includes mechanisms for negotiating the control channel and connectivity verification (i.e. OAM functions) types between PEs. These mechanisms need to be extended when a Generalised associated channel is used for e.g. MPLS LSP OAM. This will most likely require extensions to label distribution protocols and is outside the scope of this document. Bocci et al. Expires May 27, 2009 [Page 5]
Internet-Draft G-ACH and GAL November 2008 2.1. Allocation of Channel Types Values for the Channel Type field, currently used for VCCV, are specified in RFC 4446 [12]. The functionality of any additional channel types will be defined in another document. Each associated channel protocol solution document must specify the value to use for any additional channel types. 3. Generalised Exception Mechanism The above mechanism enables the multiplexing of various OAM packets onto a PW, LSP or section and provides information on the type of OAM function being performed. In the case of a PW, the use of a control word is negotiated at the time of the PW establishment. However, in the case of an MPLS LSP or section, there is a need to notify an LSR of the presence of an associated channel packet i.e. LSPs and sections require a mechanism to differentiate specific packets (e.g. OAM) from others, such as normal user-plane ones. This document proposes that a label be used and calls this special label the 'Generic Alert Label (GAL)'. One of the reserved label values defined in RFC 3032 [3] is assigned for this purpose. The value of the label is to be allocated by IANA; this document suggests the value 13. The GAL provides a generalised exception mechanism to: o Differentiate specific packets (e.g. OAM) from others, such as normal user-plane ones, o Indicate that the Generic Associated Channel Header (G-ACH) appears immediately after the bottom of the label stack. The 'Generic Alert Label (GAL)' MUST only be used where both of these purposes are applicable. 3.1. Relationship with Existing MPLS OAM Alert Mechanisms RFC 4379 [6] and BFD for MPLS LSPs [9] have defined alert mechanisms that enable a MPLS LSR to identify and process MPLS OAM packets when the OAM packets are encapsulated in an IP header. These alert mechanisms are based on TTL expiration and/or use an IP destination address in the range 127/8. Bocci et al. Expires May 27, 2009 [Page 6]
Internet-Draft G-ACH and GAL November 2008 These alert mechanisms SHOULD preferably be used in non MPLS-TP environments. The mechanism defined in this document MAY also be used. 3.2. GAL Applicability and Usage The 'Generic Alert Label (GAL)' MUST only be used with Label Switched Paths (LSPs), with their associated Tandem Connection Monitoring Entities (see [18] for definitions of TCMEs) and with MPLS Sections. An MPLS Section is a network segment between two LSRs that are immediately adjacent at the MPLS layer. The GAL applies to both P2P and P2MP LSPs, unless otherwise stated. In MPLS-TP, the GAL MUST always be at the bottom of the label stack (i.e. S bit set to 1). However, in other MPLS environments, this document places no restrictions on where the GAL may appear within the label stack. The G-ACH MUST be used for PWs when OAM functions that cannot be demultiplexed using the IP mechanisms described in section 1. The PWE3 control word MUST be present in the encapsulation of user packets when the G-ACH is used to demultiplex OAM on a PW. The GAL MUST NOT appear in the label stack when transporting normal user-plane packets. Furthermore, the GAL MUST only appear once in the label stack for OAM packets of a given layer. 3.2.1. GAL Processing The Traffic Class (TC) field (formerly known as the EXP field) of the label stack entry containing the GAL follows the definition and processing rules specified and referenced in [10]. The Time-To-Live (TTL) field of the label stack entry that contains the GAL follows the definition and processing rules specified in [4]. 3.2.1.1. MPLS Section The following figure (Figure 2) depicts two MPLS LSRs immediately adjacent at the MPLS layer. +---+ +---+ | A |-------------| Z | +---+ +---+ Figure 2 : MPLS-TP OAM over a MPLS Section Bocci et al. Expires May 27, 2009 [Page 7]
Internet-Draft G-ACH and GAL November 2008 With regards to the MPLS Section, both LERs contain Maintenance End Points (see [18] for definitions of MEPs). The following figure (Figure 3) depicts the format of a labelled OAM packet on an associated channel when used for MPLS Section OAM. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Generic-ACH | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . . MPLS-TP OAM packet . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 : Labelled MPLS-TP OAM packet for MPLS Section OAM To send an MPLS-TP OAM packet on an associated channel of the MPLS Section, the head-end LSR (A) of the MPLS Section generates a OAM packet with a G-ACH to which it pushes a GAL. o The TTL field of the GAL SHOULD be set to 1. o The S bit of the GAL MUST be set to 1. The OAM packet, the G-ACH and the GAL SHOULD NOT be modified towards the tail-end LSR (Z). Upon reception of the labelled packet, the tail-end LSR (Z), after having checked the GAL fields, SHOULD pass the whole packet to the appropriate processing entity. 3.2.1.2. Label Switched Paths The following figure (Figure 4) depicts four LSRs. A LSP is established from A to D and switched in B and C. +---+ +---+ +---+ +---+ | A |-------------| B |-------------| C |-------------| D | +---+ +---+ +---+ +---+ Figure 4 : MPLS-TP OAM over a LSP LERs A and D contain Maintenance End Points (MEPs) with respect to this LSP. Furthermore, LSRs B and C could also contain Maintenance Bocci et al. Expires May 27, 2009 [Page 8]
Internet-Draft G-ACH and GAL November 2008 Intermediate Points (MIPs) (see [18] for definitions of MEPs and MIPs). The following figure (Figure 5) depicts the format of a labelled MPLS-TP OAM packet when used for LSP OAM. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Generic-ACH | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . . MPLS-TP OAM packet . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 : Labelled MPLS-TP OAM packet for LSP OAM Note that it is possible that the LSP MAY also be tunnelled in another LSP (e.g. if an MPLS Tunnel exists between B and C), and as such other labels MAY be present above it in the label stack. To send an MPLS-TP OAM packet on the LSP, the head-end LSR (A) generates a MPLS-TP OAM packet with a G-ACH on which it first pushes a GAL followed by the LSP label. o The TTL field of the GAL SHOULD be set to 1. o The S bit of the GAL SHOULD be set to 1, in MPLS-TP. The MPLS-TP OAM packet, the G-ACH or the GAL SHOULD NOT be modified towards the targeted destination. Upon reception of the labelled packet, the targeted destination, after having checked both the LSP label and GAL fields, SHOULD pass the whole packet to the appropriate processing entity. 3.2.1.3. Tandem Connection Monitoring Entity Tandem Connection Monitoring will be specified in a separate document. Bocci et al. Expires May 27, 2009 [Page 9]
Internet-Draft G-ACH and GAL November 2008 3.3. Relationship with RFC 3429 RFC 3429 [15] describes the assignment of one of the reserved label values, defined in RFC 3032 [3], to the 'OAM Alert Label' that is used by user-plane MPLS OAM functions for the identification of MPLS OAM packets. The value of 14 is used for that purpose. Both this document and RFC 3429 therefore describe the assignment of reserved label values for similar purposes. The rationale for the assignment of a new reserved label can be summarized as follows: o Unlike the mechanisms described and referenced in RFC 3429, MPLS- TP OAM packet payloads will not reside immediately after the GAL but instead behind the G-ACH, which itself resides immediately after the bottom of the label stack when the GAL is present. This ensures that OAM using the generic associated channel complies with RFC 4928 [7]. o The set of OAM functions potentially operated in the context of the generic associated channel is wider than the set of OAM functions referenced in RFC 3429. o It has been reported that there are existing implementations and running deployments using the 'OAM Alert Label' as described in RFC 3429. It is therefore not possible to modify the 'OAM Alert Label' allocation, purpose or usage. Nevertheless, it is RECOMMENDED by this document that no further OAM extensions based on 'OAM Alert Label' (Label 14) usage be specified or developed. 4. Compatibility An LER, LSR or PE MUST discard received G-ACH packets if it is not G- ACH capable, it is not capable of processing packets on the indicated G-ACH channel, or it has not, through means outside the scope of this document, indicated to the sending LSR, LER or PE that it will process G-ACH packets received on the indicated channel. The LER, LSR or PE MAY increment an error counter and MAY also optionally issue a system and/or SNMP notification. 5. Congestion Considerations The congestion considerations detailed in RFC 5085 [8] apply. Further generic associated channel-specific congestion considerations will be detailed in a future revision of this document. Bocci et al. Expires May 27, 2009 [Page 10]
Internet-Draft G-ACH and GAL November 2008 6. Security Considerations The security considerations detailed in RFC 5085 [1], the MPLS architecture [2], the PWE3 architecture [5] and the MPLS-TP framework [17]apply. 7. IANA Considerations This document requests that IANA allocates a Label value, to the 'Generalised-ACH Label (GAL)', from the pool of reserved labels, and suggests this value to be 13. Channel Types for the Generic Associated Channel are allocated from the IANA PW Associated Channel Type registry [12]. The PW Associated Channel Type registry is currently allocated based on the IETF consensus process, described in [13]. This allocation process was chosen based on the consensus reached in the PWE3 working group that pseudowire associated channel mechanisms should be reviewed by the IETF and only those that are consistent with the PWE3 architecture and requirements should be allocated a code point. However, a requirement has emerged (see [16]) to allow for optimizations or extensions to OAM and other control protocols running in an associated channel to be experimented with without resorting to the IETF standards process, by supporting experimental code points [14]. This would prevent code points used for such functions from being used from the range allocated through the IETF standards and thus protects an installed base of equipment from potential inadvertent overloading of code points. In order to support this requirement, this document requests that the code-point allocation scheme for the PW Associated Channel Type be changed as follows: 0 - 32751 : IETF Consensus 32752 - 32767 : Experimental Code points in the experimental range MUST be used according to the guidelines of RFC 3692 [14]. Experimental OAM functions MUST be disabled by default. The channel type value used for a given experimental OAM function MUST be configurable, and care MUST be taken to ensure that different OAM functions that are not interoperable are configured to use different channel type values. Bocci et al. Expires May 27, 2009 [Page 11]
Internet-Draft G-ACH and GAL November 2008 8. Acknowledgments The authors would like to thank all members of the teams (the Joint Working Team, the MPLS Interoperability Design Team in IETF and the T-MPLS Ad Hoc Group in ITU-T) involved in the definition and specification of MPLS Transport Profile. 9. References 9.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [2] Rosen, E., Viswanathan, A., Callon, R., "Multiprotocol Label Switching Architecture", RFC 3031, January 2001 [3] Rosen, E., et al., "MPLS Label Stack Encoding", RFC 3032, January 2001 [4] Agarwal, P., Akyol, B., "Time To Live (TTL) Processing in Multi-Protocol Label Switching (MPLS) Networks", RFC 3443, January 2003 [5] Bryant, S., Pate, P., "Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture", RFC 3985, March 2005 [6] Kompella, K., Swallow, G., "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006 [7] Swallow, G., Bryant, S., Andersson, L., "Avoiding Equal Cost Multipath Treatment in MPLS Networks", BCP 128, RFC 4928, June 2007 [8] Nadeau, T., Pignataro, S., "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007 [9] Aggarwal, R., Kompella, K., Swallow, G., Nadeau, T., "BFD For MPLS LSPs", draft-ietf-bfd-mpls-07, June 2008 [10] Andersson, L., ""EXP field" renamed to "CoS Field"", draft- ietf-mpls-cosfield-def-02, June 2008 [11] Bryant, S., et al., "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN", RFC 4385, February 2006 Bocci et al. Expires May 27, 2009 [Page 12]
Internet-Draft G-ACH and GAL November 2008 [12] Martini, L., "IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)", RFC 4446, April 2006 [13] Narten, T., Alvestrand, H., " Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, October 1998 [14] Narten, T., "Assigning Experimental and Testing Numbers Considered Useful", RFC 3692, January 2004 9.2. Informative References [15] Ohta, H., "Assignment of the 'OAM Alert Label' for Multiprotocol Label Switching Architecture (MPLS) Operation and Maintenance (OAM) Functions", RFC 3429, November 2002 [16] Vigoureux, M., Betts, M., Ward, D., "Requirements for OAM in MPLS Transport Networks", draft-vigoureux-mpls-tp-oam- requirements-00, July 2008 [17] Bryant, S., Bocci, M., Lasserre, M., "A Framework for MPLS in Transport Networks", draft-ietf-mpls-tp-framework-00.txt, November 2008 [18] Busi, I., Niven-Jenkins B., "MPLS-TP OAM Framework and Overview", draft-busi-mpls-tp-oam-framework-00, October 2008 Bocci et al. Expires May 27, 2009 [Page 13]
Internet-Draft G-ACH and GAL November 2008 Authors' Addresses Martin Vigoureux (Editor) Alcatel-Lucent Email: martin.vigoureux@alcatel-lucent.com Matthew Bocci (Editor) Alcatel-Lucent Email: matthew.bocci@alcatel-lucent.com David Ward (Editor) Cisco Systems, Inc. Email: dward@cisco.com George Swallow (Editor) Cisco Systems, Inc. Email: swallow@cisco.com Rahul Aggarwal (Editor) Juniper Networks Email: rahul@juniper.net Contributing Authors' Addresses Stewart Bryant Cisco Systems, Inc. Email: stbryant@cisco.com Italo Busi Alcatel-Lucent Email: italo.busi@alcatel-lucent.it Bocci et al. Expires May 27, 2009 [Page 14]
Internet-Draft G-ACH and GAL November 2008 Marc Lasserre Alcatel-Lucent Email: mlasserre@alcatel-lucent.com Lieven Levrau Alcatel-Lucent Email: llevrau@alcatel-lucent.com Intellectual Property Statement 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, THE IETF TRUST 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. Bocci et al. Expires May 27, 2009 [Page 15]
Internet-Draft G-ACH and GAL November 2008 Copyright Statement Copyright (C) The IETF Trust (2008). 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. Bocci et al. Expires May 27, 2009 [Page 16]
