Network Working Group J. Schoenwaelder, Ed. Internet-Draft Jacobs University Intended status: Standards Track July 14, 2008 Expires: January 15, 2009 Common YANG Data Types draft-schoenw-netmod-yang-types-01 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 January 15, 2009. Copyright Notice Copyright (C) The IETF Trust (2008). Schoenwaelder Expires January 15, 2009 [Page 1] Internet-Draft YANG-TYPES July 2008 Abstract This document introduces a collection of common data types to be used with the YANG data modeling language. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Key Words . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Core YANG Derived Types . . . . . . . . . . . . . . . . . . . 5 4. Internet Specific Derived Types . . . . . . . . . . . . . . . 11 5. IEEE 802 Specific Derived Types . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 7. Security Considerations . . . . . . . . . . . . . . . . . . . 21 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 22 9. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 23 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24 10.1. Normative References . . . . . . . . . . . . . . . . . . 24 10.2. Informative References . . . . . . . . . . . . . . . . . 24 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 25 Intellectual Property and Copyright Statements . . . . . . . . . . 26 Schoenwaelder Expires January 15, 2009 [Page 2] Internet-Draft YANG-TYPES July 2008 1. Introduction YANG [YANG] is a data modeling language used to model configuration and state data manipulated by the NETCONF [RFC4741] protocol. The YANG language supports a small set of built-in data types and provides mechanisms to derive other types from the built-in types. This document introduces a collection of common data types derived from the built-in YANG data types. The definitions are organized in several YANG modules. The "yang-types" module contains generally useful data types. The "inet-types" module contains definitions that are relevant for the Internet protocol suite while the "ieee-types" module contains definitions that are relevant for IEEE 802 protocols. Their derived types are generally designed to be applicable for modeling all areas of management information. Schoenwaelder Expires January 15, 2009 [Page 3] Internet-Draft YANG-TYPES July 2008 2. Key Words The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. Schoenwaelder Expires January 15, 2009 [Page 4] Internet-Draft YANG-TYPES July 2008 3. Core YANG Derived Types module yang-types { // XXX namespace to be allocated by IANA namespace "urn:ietf:params:xml:ns:yang:yang-types"; prefix "yang"; organization "YANG Language Design Team"; contact "Juergen Schoenwaelder (Editor) "; description "This module contains standard derived YANG types."; revision 2009-05-22 { description "Initial revision."; } /* * collection of counter and gauge types */ typedef counter32 { type uint32; description "The counter32 type represents a non-negative integer which monotonically increases until it reaches a maximum value of 2^32-1 (4294967295 decimal), when it wraps around and starts increasing again from zero. Counters have no defined `initial' value, and thus, a single value of a counter has (in general) no information content. Discontinuities in the monotonically increasing value normally occur at re-initialization of the management system, and at other times as specified in the description of an object instance using this type. If such other times can occur, for example, the creation of an object instance of type counter32 at times other than re-initialization, then a corresponding object should be defined, with an appropriate type, to indicate the last discontinuity. The counter32 type should not be used for configuration Schoenwaelder Expires January 15, 2009 [Page 5] Internet-Draft YANG-TYPES July 2008 objects. A default statement should not be used for attributes with a type value of counter32."; reference "RFC 2578 (STD 58)"; } typedef zero-based-counter32 { type yang:counter32; default "0"; description "The zero-based-counter32 type represents a counter32 which has the defined `initial' value zero."; reference "RFC 2021"; } typedef counter64 { type uint64; description "The counter64 type represents a non-negative integer which monotonically increases until it reaches a maximum value of 2^64-1 (18446744073709551615), when it wraps around and starts increasing again from zero. Counters have no defined `initial' value, and thus, a single value of a counter has (in general) no information content. Discontinuities in the monotonically increasing value normally occur at re-initialization of the management system, and at other times as specified in the description of an object instance using this type. If such other times can occur, for example, the creation of an object instance of type counter64 at times other than re-initialization, then a corresponding object should be defined, with an appropriate type, to indicate the last discontinuity. The counter64 type should not be used for configuration objects. A default statement should not be used for attributes with a type value of counter64."; reference "RFC 2578 (STD 58)"; } typedef zero-based-counter64 { type yang:counter64; default "0"; description "The zero-based-counter64 type represents a counter64 Schoenwaelder Expires January 15, 2009 [Page 6] Internet-Draft YANG-TYPES July 2008 which has the defined `initial' value zero."; reference "RFC 2856"; } typedef gauge32 { type uint32; description "The gauge32 type represents a non-negative integer, which may increase or decrease, but shall never exceed a maximum value, nor fall below a minimum value. The maximum value can not be greater than 2^32-1 (4294967295 decimal), and the minimum value can not be smaller than 0. The value of a gauge32 has its maximum value whenever the information being modeled is greater than or equal to its maximum value, and has its minimum value whenever the information being modeled is smaller than or equal to its minimum value. If the information being modeled subsequently decreases below (increases above) the maximum (minimum) value, the gauge32 also decreases (increases)."; reference "RFC 2578 (STD 58)"; } typedef gauge64 { type uint64; description "The gauge64 type represents a non-negative integer, which may increase or decrease, but shall never exceed a maximum value, nor fall below a minimum value. The maximum value can not be greater than 2^64-1 (18446744073709551615), and the minimum value can not be smaller than 0. The value of a gauge64 has its maximum value whenever the information being modeled is greater than or equal to its maximum value, and has its minimum value whenever the information being modeled is smaller than or equal to its minimum value. If the information being modeled subsequently decreases below (increases above) the maximum (minimum) value, the gauge64 also decreases (increases)."; reference "RFC 2856"; } /* Schoenwaelder Expires January 15, 2009 [Page 7] Internet-Draft YANG-TYPES July 2008 * collection of identifier related types */ typedef uri { type string; description "A uri type represents Uniform Resource Identifier (URI) as defined by STD 66. Objects using this type MUST be in US-ASCII encoding, and MUST be normalized as described by RFC 3986 Sections 6.2.1, 6.2.2.1, and 6.2.2.2. All unnecessary percent-encoding is removed, and all case-insensitive characters are set to lowercase except for hexadecimal digits, which are normalized to uppercase as described in Section 6.2.2.1. The purpose of this normalization is to help provide unique URIs. Note that this normalization is not sufficient to provide uniqueness. Two URIs that are textually distinct after this normalization may still be equivalent. Objects using this type MAY restrict the schemes that they permit. For example, 'data:' and 'urn:' schemes might not be appropriate. A zero-length URI is not a valid URI. This can be used to express 'URI absent' where required, for example when used as an index field."; reference "RFC 3986 (STD 66), RFC 3305, and RFC 5017"; } typedef object-identifier { type string { pattern '([0-1](\.[1-3]?[0-9]))|(2.(0|([1-9]\d*)))' + '(\.(0|([1-9]\d*)))*'; } description "The object-identifier type represents administratively assigned names in a registration-hierarchical-name tree. Values of this type are denoted as a sequence of numerical non-negative sub-identifier values. Each sub-identifier value MUST NOT exceed 2^32-1 (4294967295). Sub-identifiers are separated by single dots and without any intermediate white space. Schoenwaelder Expires January 15, 2009 [Page 8] Internet-Draft YANG-TYPES July 2008 Although the number of sub-identifiers is not limited, module designers should realize that there may be implementations that stick with the SMIv1/v2 limit of 128 sub-identifiers."; reference "ITU-T Recommendation X.660 / ISO/IEC 9834-1"; } /* * collection of date and time related types */ typedef date-and-time { type string { pattern '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.d*)?' + '(Z|(\+|-)\d{2}:\d{2})'; } description 'The date-and-time type is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar. The format is most easily described using the following ABFN (see RFC 3339): date-fullyear = 4DIGIT date-month = 2DIGIT ; 01-12 date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 time-hour = 2DIGIT ; 00-23 time-minute = 2DIGIT ; 00-59 time-second = 2DIGIT ; 00-58, 00-59, 00-60 time-secfrac = "." 1*DIGIT time-numoffset = ("+" / "-") time-hour ":" time-minute time-offset = "Z" / time-numoffset partial-time = time-hour ":" time-minute ":" time-second [time-secfrac] full-date = date-fullyear "-" date-month "-" date-mday full-time = partial-time time-offset date-time = full-date "T" full-time'; reference "RFC 3339"; } typedef timeticks { type uint32; description "The timeticks type represents a non-negative integer which represents the time, modulo 2^32 (4294967296 decimal), in hundredths of a second between two epochs. Schoenwaelder Expires January 15, 2009 [Page 9] Internet-Draft YANG-TYPES July 2008 When objects are defined which use this type, the description of the object identifies both of the reference epochs."; reference "RFC 2578 (STD 58)"; } typedef timestamp { type yang:timeticks; description "The timestamp type represents the value of an associated timeticks object at which a specific occurrence happened. The specific occurrence must be defined in the description of any object defined using this type. When the specific occurrence occurred prior to the last time the associated timeticks attribute was zero, then the timestamp value is zero. Note that this requires all timestamp values to be reset to zero when the value of the associated timeticks attribute reaches 497+ days and wraps around to zero. The associated timeticks object must be specified in the description of any object using this type."; reference "RFC 2579 (STD 58)"; } /* * collection of generic address types */ typedef phys-address { type string; description "Represents media- or physical-level addresses."; reference "RFC 2579 (STD 58)"; } } Schoenwaelder Expires January 15, 2009 [Page 10] Internet-Draft YANG-TYPES July 2008 4. Internet Specific Derived Types module inet-types { // XXX namespace to be allocated by IANA namespace "urn:ietf:params:xml:ns:yang:inet-types"; prefix "inet"; organization "YANG Language Design Team"; contact "Juergen Schoenwaelder (Editor) "; description "This module contains standard derived YANG types for Internet addresses and related things."; revision 2008-06-07 { description "Initial revision."; } /* * collection of protocol field related types */ typedef ip-version { type enumeration { enum unknown { value 0; description "An unknown or unspecified version of the Internet protocol."; } enum ipv4 { value 1; description "The IPv4 protocol as defined in RFC 791."; } enum ipv6 { value 2; description "The IPv6 protocol as defined in RFC 2460."; } } description Schoenwaelder Expires January 15, 2009 [Page 11] Internet-Draft YANG-TYPES July 2008 "This value represents the version of the IP protocol."; reference "RFC 791 (STD 5), RFC 2460"; } typedef dscp { type uint8 { range "0..63"; } description "The dscp type represents a Differentiated Services Code-Point that may be used for marking a traffic stream."; reference "RFC 3289, RFC 2474, RFC 2780"; } typedef flow-label { type uint32 { range "0..1048575"; } description "The flow-label type represents flow identifier or Flow Label in an IPv6 packet header that may be used to discriminate traffic flows."; reference "RFC 2460"; } typedef port-number { type uint16 { range "1..65535"; } description "The port-number type represents a 16-bit port number of an Internet transport layer protocol such as UDP, TCP, DCCP or SCTP. Port numbers are assigned by IANA. A current list of all assignments is available from . Note that the value zero is not a valid port number. A union type might be used in situations where the value zero is meaningful."; reference "RFC 4001"; } Schoenwaelder Expires January 15, 2009 [Page 12] Internet-Draft YANG-TYPES July 2008 /* * collection of autonomous system related types */ typedef as-number { type uint32; description "The as-number type represents autonomous system numbers which identify an Autonomous System (AS). An AS is a set of routers under a single technical administration, using an interior gateway protocol and common metrics to route packets within the AS, and using an exterior gateway protocol to route packets to other ASs'. IANA maintains the AS number space and has delegated large parts to the regional registries. Autonomous system numbers are currently limited to 16 bits (0..65535). There is however work in progress to enlarge the autonomous system number space to 32 bits. This textual convention therefore uses an uint32 base type without a range restriction in order to support a larger autonomous system number space."; reference "RFC 1771, RFC 1930, RFC 4001"; } /* * collection of IP address and hostname related types */ typedef ip-address { type union { type inet:ipv4-address; type inet:ipv6-address; } description "The ip-address type represents an IP address and is IP version neutral. The format of the textual representations implies the IP version."; } typedef ipv4-address { type string { pattern '(([0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])\.){3}' + '([0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])' + '(%[\p{N}\p{L}]+)?'; } Schoenwaelder Expires January 15, 2009 [Page 13] Internet-Draft YANG-TYPES July 2008 description "The ipv4-address type represents an IPv4 address in dotted-quad notation. The IPv4 address may include a zone index, separated by a % sign. The zone index is used to disambiguate identical address values. For link-local addresses, the zone index will typically be the interface index number or the name of an interface. If the zone index is not present, the default zone of the device will be used."; } typedef ipv6-address { type string { pattern /* full */ '((([0-9a-fA-F]{1,4}:){7})([0-9a-fA-F]{1,4})' + '(%[\p{N}\p{L}]+)?)' /* mixed */ + '|((([0-9a-fA-F]{1,4}:){6})(([0-9]{1,3}\.' + '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))' + '(%[\p{N}\p{L}]+)?)' /* shortened */ + '|((([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*(::)' + '(([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*' + '(%[\p{N}\p{L}]+)?)' /* shortened mixed */ + '((([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*(::)' + '(([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*' + '(([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))' + '(%[\p{N}\p{L}]+)?)'; } description "The ipv6-address type represents an IPv6 address in full, mixed, shortened and shortened mixed notation. The IPv6 address may include a zone index, separated by a % sign. The zone index is used to disambiguate identical address values. For link-local addresses, the zone index will typically be the interface index number or the name of an interface. If the zone index is not present, the default zone of the device will be used."; reference "RFC 4007: IPv6 Scoped Address Architecture"; } typedef ip-prefix { Schoenwaelder Expires January 15, 2009 [Page 14] Internet-Draft YANG-TYPES July 2008 type union { type inet:ipv4-prefix; type inet:ipv6-prefix; } description "The ip-prefix type represents an IP prefix and is IP version neutral. The format of the textual representations implies the IP version."; } typedef ipv4-prefix { type string { pattern '(([0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])\.){3}' + '([0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])' + '/\p{N}+'; } description "The ipv4-prefix type represents an IPv4 address prefix. The prefix length is given by the number following the slash character and must be less than or equal 32. A prefix length value of n corresponds to an IP address mask which has n contiguous 1-bits from the most significant bit (MSB) and all other bits set to 0. The IPv4 address represented in dotted quad notation should have all bits that do not belong to the prefix set to zero."; } typedef ipv6-prefix { type string { pattern /* full */ '((([0-9a-fA-F]{1,4}:){7})([0-9a-fA-F]{1,4})' + '/\p{N}+)' /* mixed */ + '|((([0-9a-fA-F]{1,4}:){6})(([0-9]{1,3}\.' + '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))' + '/\p{N}+)' /* shortened */ + '|((([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*(::)' + '(([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*' + '/\p{N}+)' /* shortened mixed */ + '((([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*(::)' + '(([0-9a-fA-F]{1,4}:)*([0-9a-fA-F]{1,4}))*' Schoenwaelder Expires January 15, 2009 [Page 15] Internet-Draft YANG-TYPES July 2008 + '(([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))' + '/\p{N}+)'; } description "The ipv6-prefix type represents an IPv6 address prefix. The prefix length is given by the number following the slash character and must be less than or equal 128. A prefix length value of n corresponds to an IP address mask which has n contiguous 1-bits from the most significant bit (MSB) and all other bits set to 0. The IPv6 address should have all bits that do not belong to the prefix set to zero."; } /* * Domain name and URI types. */ typedef domain-name { type string { pattern '([a-zA-Z0-9\-]+\.)*[a-zA-Z0-9\-]+'; } description "The domain-name type represents a DNS domain name. The name SHOULD be fully qualified whenever possible. The description clause of objects using the domain-name type MUST describe how (and when) these names are resolved to IP addresses. Note that the resolution of a domain-name value may require to query multiple DNS records (e.g., A for IPv4 and AAAA for IPv6). The order of the resolution process and which DNS record takes precedence depends on the configuration of the resolver."; reference "RFC 1034"; } typedef host { type union { type inet:ip-address; type inet:domain-name; } Schoenwaelder Expires January 15, 2009 [Page 16] Internet-Draft YANG-TYPES July 2008 description "The host type represents either an IP address or a DNS domain name."; } typedef uri { type string; // TBD: add the regex from RFC 3986 here? description "The uri type represents a Uniform Resource Identifier (URI) as defined by STD 66. Objects using the uri type must be in US-ASCII encoding, and MUST be normalized as described by RFC 3986 Sections 6.2.1, 6.2.2.1, and 6.2.2.2. All unnecessary percent-encoding is removed, and all case-insensitive characters are set to lowercase except for hexadecimal digits, which are normalized to uppercase as described in Section 6.2.2.1. The purpose of this normalization is to help provide unique URIs. Note that this normalization is not sufficient to provide uniqueness. Two URIs that are textually distinct after this normalization may still be equivalent. Objects using the uri type may restrict the schemes that they permit. For example, 'data:' and 'urn:' schemes might not be appropriate. A zero-length URI is not a valid URI. This can be used to express 'URI absent' where required." reference "RFC 3986 STD 66 and RFC 3305" } } Schoenwaelder Expires January 15, 2009 [Page 17] Internet-Draft YANG-TYPES July 2008 5. IEEE 802 Specific Derived Types module ieee-types { // XXX namespace to be allocated by IANA namespace "urn:ietf:params:xml:ns:yang:ieee-types"; prefix "ieee"; import yang-types { prefix yang; } organization "YANG Language Design Team"; contact "Juergen Schoenwaelder (Editor) "; description "This module contains standard derived YANG types for IEEE 802 addresses and related things."; revision 2008-05-22 { description "Initial revision."; } /* * collection of IEEE address type definitions */ typedef mac-address { type yang:phys-address { pattern '([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}'; } description "The mac-address type represents an 802 MAC address represented in the `canonical' order defined by IEEE 802.1a, i.e., as if it were transmitted least significant bit first, even though 802.5 (in contrast to other 802.x protocols) requires MAC addresses to be transmitted most significant bit first."; reference "RFC 2579 STD 58"; } /* Schoenwaelder Expires January 15, 2009 [Page 18] Internet-Draft YANG-TYPES July 2008 * collection of IEEE 802 related identifier types */ typedef bridgeid { type string { pattern '[0-9a-fA-F]{4}:' + '([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}'; } description "The bridgeid type represents identifers that uniquely identify a bridge. Its first four hexadecimal digits contain a priority value followed by a colon. The remaining characters contain the MAC address used to refer to a bridge in a unique fashion (typically, the numerically smallest MAC address of all ports on the bridge)."; reference "RFC 4188"; } typedef vlanid { type uint16 { range "1..4094"; } description "The vlanid type uniquely identifies a VLAN. This is the 12-bit VLAN-ID used in the VLAN Tag header. The range is defined by the referenced specification."; reference "IEEE Std 802.1Q 2003 Edition, Virtual Bridged Local Area Networks."; } } Schoenwaelder Expires January 15, 2009 [Page 19] Internet-Draft YANG-TYPES July 2008 6. IANA Considerations A registry for standard YANG modules shall be set up. Each entry shall contain the unique module name, the unique XML namespace from the YANG URI Scheme and some reference to the module's documentation. This document registers three URIs for the YANG XML namespace in the IETF XML registry [RFC3688]. URI: urn:ietf:params:xml:ns:yang:ieee-types URI: urn:ietf:params:xml:ns:yang:inet-types URI: urn:ietf:params:xml:ns:yang:yang-types Schoenwaelder Expires January 15, 2009 [Page 20] Internet-Draft YANG-TYPES July 2008 7. Security Considerations This document defines common data types using the YANG data modeling language. The definitions themselves have no security impact on the Internet but the usage of these definitions in concrete YANG modules might have. The security considerations spelled out in the YANG specification [YANG] apply for this document as well. Schoenwaelder Expires January 15, 2009 [Page 21] Internet-Draft YANG-TYPES July 2008 8. Contributors The following people all contributed significantly to the initial version of this draft: - Andy Bierman (andybierman.com) - Martin Bjorklund (Tail-f Systems) - Balazs Lengyel (Ericsson) - David Partain (Ericsson) - Phil Shafer (Juniper Networks) Schoenwaelder Expires January 15, 2009 [Page 22] Internet-Draft YANG-TYPES July 2008 9. Open Issues - Should YANG allow multiple pattern that get ANDed? This would for example allow to tighten the IPv6 pattern. Message-Id: <1215432618.23783.59.camel@missotis> - Add some common reusable groupings, e.g. a combination of ip-address and port-number? Or should such groupings be a separate document? Schoenwaelder Expires January 15, 2009 [Page 23] Internet-Draft YANG-TYPES July 2008 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [YANG] Bjorklund, M., Ed., "YANG - A data modeling language for NETCONF", draft-ietf-netmod-yang-00 (work in progress). 10.2. Informative References [RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741, December 2006. Schoenwaelder Expires January 15, 2009 [Page 24] Internet-Draft YANG-TYPES July 2008 Author's Address Juergen Schoenwaelder (editor) Jacobs University Email: j.schoenwaelder@jacobs-university.de Schoenwaelder Expires January 15, 2009 [Page 25] Internet-Draft YANG-TYPES July 2008 Full 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. 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. Intellectual Property 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. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Schoenwaelder Expires January 15, 2009 [Page 26]