Network Working Group D. Ellard Internet-Draft BBN Technologies Intended status: Standards Track C. Everhart Expires: March 30, 2009 J. Lentini NetApp R. Tewari M. Naik IBM Almaden September 26, 2008 Administration Protocol for Federated Filesystems draft-ietf-nfsv4-federated-fs-admin-00.txt 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 March 30, 2009. Copyright Notice Copyright (C) The IETF Trust (2008). Ellard, et al. Expires March 30, 2009 [Page 1] Internet-Draft Admin Protocol for Federated Filesystems September 2008 Abstract This document describes the administration protocol for a federated file system that enables file access and namespace traversal across collections of independently administered fileservers. The protocol specifies a set of interfaces by which fileservers and collections of fileservers with different administrators can form a fileserver federation that provides a namespace composed of the filesystems physically hosted on and exported by the constituent fileservers. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Error Definitions . . . . . . . . . . . . . . . . . . . . . . 5 4. Administrator-Initiated Operations . . . . . . . . . . . . . . 7 4.1. Basic Definition . . . . . . . . . . . . . . . . . . . . . 7 4.2. Required Operations . . . . . . . . . . . . . . . . . . . 8 4.2.1. CREATE_JUNCTION . . . . . . . . . . . . . . . . . . . 9 4.2.2. DELETE_JUNCTION . . . . . . . . . . . . . . . . . . . 10 4.2.3. LOOKUP_FSN . . . . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. IANA Requirements . . . . . . . . . . . . . . . . . . . . . . 14 7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 15 8. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 9. Normative References . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Intellectual Property and Copyright Statements . . . . . . . . . . 22 Ellard, et al. Expires March 30, 2009 [Page 2] Internet-Draft Admin Protocol for Federated Filesystems September 2008 1. Requirements notation 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 [RFC2119]. Ellard, et al. Expires March 30, 2009 [Page 3] Internet-Draft Admin Protocol for Federated Filesystems September 2008 2. Introduction A federated filesystem enables file access and namespace traversal in a uniform, secure and consistent manner across multiple independent fileservers within an enterprise (and possibly across multiple enterprises) with reasonably good performance. The first requirement of a federated filesystem is the ability to traverse the data exported by different fileservers without requiring a static client configuration. The second requirement is that the location of the data should be dynamically discovered and the discovery process should be transparent to the clients. The third requirement is that it should be possible for all clients, with sufficient privilege, to view the same namespace regardless of the fileserver they connect to. Traditionally, fileserver collections are administered by a single entity. Fileservers may provide proprietary management tools and in some cases an administrator may be able to use the proprietary tools to build a shared namespace out of the exported filesystems. Relying on vendor-proprietary tools does not work in larger enterprises or when collaborating across enterprises because it is likely that the system will contain fileservers running different software, each with their own interfaces, with no common protocol to manage the namespace or exchange namespace information. There may also be independently- administered singleton servers that export some or all of their filesystem resources. A filesystem federation protocol enables the interoperation across multi-vendor fileservers managed by the same administrative entity, across singleton independent fileservers, and across independent administrative entities that may manage a collection of fileservers. The scope of the filesystem federation protocol is limited to NFSv4 capable fileservers. The support for NFSv3 fileservers is optional. The basic requirements for a federated file system protocol are described in IETF draft draft-ellard-nfsv4-federated-fs-reqts, and the current proposed protocol is described in draft-tewari-nfsv4-federated-fs-protocol. Those drafts are companions (and essential background material) to this document. Please refer to those documents for the definitions of basic terms and concepts used in this document. Ellard, et al. Expires March 30, 2009 [Page 4] Internet-Draft Admin Protocol for Federated Filesystems September 2008 3. Error Definitions The results of successful operations will consist of a status of FEDFS_OK. The results of unsuccessful operations will begin with a status, other than FEDFS_OK, that indicates the reason why the operation failed. Many of the error status names and meanings (and the prose for their descriptions) are taken from the specification for NFSv4 [RFC3530]. Note, however, that the literal values for the status codes are different. Note that the status of an unsuccessful operation will generally only indicate the first error encountered during the attempt to execute the operation. FEDFS_OK No errors were encountered. The operation was a success. FEDFS_ERR_ACCESS Permission denied. The caller does not have the correct permission to perform the requested operation. FEDFS_ERR_BADCHAR A UTF-8 string contains a character which is not supported by the server in the context in which it being used. FEDFS_ERR_BADXDR The server encountered an XDR decoding error while processing an operation. FEDFS_ERR_EXIST The junction specified already exists. FEDFS_ERR_INVAL Invalid argument for an operation. FEDFS_ERR_IO A hard error occurred while processing the requested operation. FEDFS_ERR_NOSPC The requested operation would have caused the server's filesystem to exceed some limit (for example, if there is a fixed number of junctions per fileset or per server). FEDFS_ERR_NOTDIR The caller specified a non-directory in an operation that requires a directory. FEDFS_ERR_NOTEMPTY The caller specified a directory that is not empty as the operand of an operation that requires an empty directory. Ellard, et al. Expires March 30, 2009 [Page 5] Internet-Draft Admin Protocol for Federated Filesystems September 2008 FEDFS_ERR_NOTJUNCT The caller specified a path that does not end in a junction as the operand for an operation that requires the last component of the path to be a junction. FEDFS_ERR_NOTLOCAL The caller specified a path that contains a junction in any position other than the last component. FEDFS_ERR_PERM The operation was not allowed because the caller is either not a privileged user or not the owner of an object that would be modified by the operation. FEDFS_ERR_ROFS A modifying operation was attempted on a read-only filesystem. FEDFS_ERR_SVRFAULT An unanticipated non-protocol error occurred on the server. Ellard, et al. Expires March 30, 2009 [Page 6] Internet-Draft Admin Protocol for Federated Filesystems September 2008 4. Administrator-Initiated Operations The RPC protocol used by the administration operations is ONC RPC [RFC1831]. The data structures used for the parameters and return values of these procedures are expressed in this document in XDR [RFC4506]. In contrast to earlier designs (which are not described in this document), the current admin/server interface is very simple. A server is relatively oblivious to the existence of junctions that target the filesets it exports: the target server does not play an essential role in the creation of junctions that reference them. 4.1. Basic Definition We begin by defining basic constants and structs, in XDR notation, that will be used to specify the types of the RPCs described in the rest of this subsection. enum FedFsStatus { FEDFS_OK = 0, FEDFS_ERR_ACCESS = 1, FEDFS_ERR_BADCHAR = 2, FEDFS_ERR_BADXDR = 3, FEDFS_ERR_EXIST = 4, FEDFS_ERR_INVAL = 5, FEDFS_ERR_IO = 6, FEDFS_ERR_NOSPC = 7, FEDFS_ERR_NOTDIR = 8, FEDFS_ERR_NOTEMPTY = 9, FEDFS_ERR_NOTJUNCT = 10, FEDFS_ERR_NOTLOCAL = 11, FEDFS_ERR_PERM = 12, FEDFS_ERR_ROFS = 13, FEDFS_ERR_SVRFAULT = 14 }; typedef opaque FedFsFsnUuid<64>; Ellard, et al. Expires March 30, 2009 [Page 7] Internet-Draft Admin Protocol for Federated Filesystems September 2008 typedef opaque FedFsHostName<128>; typedef opaque FedFsNsdbName<256>; typedef opaque FedFsPathName<1024>; struct FedFsFsn { FedFsFsnUuid fsnUuid; FedFsNsdbName nsdbName; }; struct FedFsCreateJunctionArgs { FedFsPathName path; FedFsFsn fsn; FedFsUuid junctionKey; }; union FedFsLookupFsnRes switch (FedFsStatus status) { case FEDFS_OK: FedFsFsn fsn; default: void; }; program FEDFS_PROG { version FEDFS_VERSION { void NULL(void) = 0; FedFsStatus CREATE_JUNCTION(FedFsCreateJunctionArgs args) = 1; FedFsStatus DELETE_JUNCTION(FedFsPathName path) = 2; FedFsLookupFsnRes LOOKUP_FSN(FedFsPathName path) = 3; } = 1; } = 100205; 4.2. Required Operations There are three operations that servers MUST implement provide in order to serve as "internal" nodes in the federated namespace: NULL The null RPC, which is included, by convention, in every ONC RPC protocol. CREATE_JUNCTION Create a new junction from some location on the server (defined as a pathname) to an FSN. DELETE_JUNCTION Delete an existing junction from some location on the server (defined as a pathname). Ellard, et al. Expires March 30, 2009 [Page 8] Internet-Draft Admin Protocol for Federated Filesystems September 2008 LOOKUP_FSN Query the server to discover the current value of the junction (if any) at a given path in the server namespace. The CREATE_JUNCTION, DELETE_JUNCTION, and LOOKUP_FSN operations are described in more detail in the following sections. Servers that implement "leaf" nodes in the namespace (i.e., servers that host filesets that are the target of junctions, but that do not contain any junctions) are not required to implement any of these operations. Note that operations that modify the state of a replicated fileset MUST result in the update of all of the replicas in a consistent manner. Ideally all of the replicas SHOULD be updated before any operation returns. If one or more of the replicas are unavailable, the operation MAY succeed, but the changes MUST be applied before the unavailable replicas are brought back online. We assume that replicas are updated via some protocol that permits state changes to be reflected consistently across the set of replicas in such a manner that the replicas will converge to a consistent state within a bounded number of successful message exchanges between the servers hosting the replicas. 4.2.1. CREATE_JUNCTION This operation creates a junction from a server-relative path to a (potentially) remote fileset named by the given FSN. We assume that the junction directory on the server is named by a pathname (or other arbitrary UTF-8 string that has a well-defined interpretation by the server). It is not required that this path be accessible in any other manner (e.g., to a client). This path does not appear in the federated namespace, except by coincidence; there is no requirement that the global namespace parallel the server namespace, nor is it required that this path be relative to the server pseudo-root. It does not need to be a path that is accessible via NFS (although the junction will be of limited utility if the directory specified by the path is not also accessible via NFS). If the fileset is read-only, then this operation SHOULD indicate this with a status of FEDFS_ERR_ROFS. If the path contains an invalid UTF-8 character, then status FEDFS_ERR_BADCHAR must be returned. The path is REQUIRED to exist and be completely local to the server. It MUST NOT contain a junction. If the last component of the path is a junction (i.e., this operation is attempting to create a junction Ellard, et al. Expires March 30, 2009 [Page 9] Internet-Draft Admin Protocol for Federated Filesystems September 2008 where one already exists), then this operation MUST return the error FEDFS_ERR_EXISTS (even if the requested junction is identical to the current junction). If any other component of the path is a junction, then this operation MUST fail with status FEDFS_ERR_NOTLOCAL. The path may contain a symbolic link (if supported by the local server), but the traversal of the path must remain within the server-local namespace. The last component of the path MUST be an empty directory. If any component of the path does not exist, or the final component is not a directory, then the operation fails with status FEDFS_ERR_INVAL. The server MAY enforce the local permissions on the path, including the final component. If the path cannot be traversed because of insufficient permissions, or the final component is an unexecutable or unwritable directory, then the operation MAY fail with status FEDFS_ERR_ACCESS. The association between the path and the FSN MUST be durable before the operation may return successfully. If the operation return codes indicates success, then the caller may assume that the junction was successfully created and is immediately accessible. If successful, subsequent references via NFSv4 clients to the directory that has been replaced by junction will result in a referral to a current location of the target fileset (as described in draft-tewari-nfsv4-federated-fs-protocol). Note that the effective permissions of the directory that is converted, by this operation, into a junction are the permissions of the root directory of the target fileset. The original permissions of the directory (and any other attributes it might have) are subsumed by the junction. Note that this operation does not create a junction from an arbitrary location in the namespace to another location in the namespace. Such an operation can be synthesized from other protocol operations, but is not primitive. It cannot be used, for example, to create the initial link to a fileset. 4.2.2. DELETE_JUNCTION This operation removes a junction specified by a server-relative path. As with CREATE_JUNCTION, we assume that the junction on the server is named by a pathname (or other arbitrary UTF-8 string that has a well- defined interpretation by the server). It is not required that this Ellard, et al. Expires March 30, 2009 [Page 10] Internet-Draft Admin Protocol for Federated Filesystems September 2008 path be accessible in any other manner (e.g., to a client). This path does not appear in the federated namespace, except by coincidence; there is no requirement that the global namespace reflect the server namespace, nor is it required that this path be relative to the server pseudo-root. It does not need to be a path that is accessible via NFS. If the fileset is read-only, then this operation SHOULD indicate this with a status of FEDFS_ERR_ROFS. If the path contains an invalid UTF-8 character, then status FEDFS_ERR_BADCHAR must be returned. It is NOT REQUIRED that the path used to delete a junction is the same path that was used to create the junction. If the namespace on the server has changed, then the junction may now appear at a different path than where it was created. If there is more than one valid path to the junction, any of them may be used. The path is REQUIRED to exist and be completely local to the server. It MUST NOT contain a junction, except as the final component, which MUST be a junction. If any other component of the path is a junction, then this operation MUST fail with status FEDFS_ERR_NOTLOCAL. If the last component of the path is not a junction then this operation MUST return status FEDFS_ERR_INVAL. The path may contain a symbolic link (if supported by the local server), but the traversal of the path must remain within the server-local namespace. The last component of the path MUST be a junction. If any component of the path does not exist, or the final component is not a junction, then the operation fails with status FEDFS_ERR_NOTJUNCT. The server MAY enforce the local permissions on the path, including the final component. If the path cannot be traversed because of insufficient permissions, or the parent directory of the junction unexecutable or unwritable directory, then the operation MAY fail with status FEDFS_ERR_ACCESS. The removal of the association between the path and the FSN MUST be durable before the operation may return successfully. If the operation return codes indicates success, then the caller may assume that the junction was successfully destroyed. The effective permissions and other attributes of the directory that is restored by this operation SHOULD be identical to their value prior to the creation of the junction. Ellard, et al. Expires March 30, 2009 [Page 11] Internet-Draft Admin Protocol for Federated Filesystems September 2008 4.2.3. LOOKUP_FSN This operation queries a server to determine whether a given path ends in a junction, and if so, the FSN to which the junction refers. Ordinary NFSv4 operations do not provide any general mechanism to determine whether an object is a junction -- there is no encoding specified by the NFSv4 protocol that can represent this information. As with CREATE_JUNCTION, we assume that any junction on the server can be named by a pathname (or other arbitrary UTF-8 string that has a well-defined interpretation by the server). It is not required that this path be accessible in any other manner (e.g., to a client). This path does not appear in the federated namespace, except by coincidence; there is no requirement that the global namespace reflect the server namespace, nor is it required that this path be relative to the server pseudo-root. It does not need to be a path that is accessible via NFS. If the path contains an invalid UTF-8 character, then status FEDFS_ERR_BADCHAR must be returned. It is NOT REQUIRED that the path used to lookup a junction is the same path that was used to create the junction. If the namespace on the server has changed, then a junction may now appear at a different path than where it was created. If there is more than one valid path to the junction, any of them may be used. The path is REQUIRED to exist and be completely local to the server. It MUST NOT contain a junction, except as the final component. If any other component of the path is a junction, then this operation MUST fail with status FEDFS_ERR_NOTLOCAL. If the last component of the path is not a junction then this operation MUST return the status FEDFS_ERR_NOTJUNCT. The path may contain a symbolic link (if supported by the local server), but the traversal of the path must remain within the server-local namespace. The server MAY enforce the local permissions on the path, including the final component. If the path cannot be traversed because of insufficient permissions, or the parent directory of the junction unexecutable or unwritable directory, then the operation MAY fail with status FEDFS_ERR_ACCESS. Ellard, et al. Expires March 30, 2009 [Page 12] Internet-Draft Admin Protocol for Federated Filesystems September 2008 5. Security Considerations To be added. Ellard, et al. Expires March 30, 2009 [Page 13] Internet-Draft Admin Protocol for Federated Filesystems September 2008 6. IANA Requirements The RPC protocol must be assigned a valid and reserved ONC RPC protocol number. Ellard, et al. Expires March 30, 2009 [Page 14] Internet-Draft Admin Protocol for Federated Filesystems September 2008 7. Conclusions The federated filesystem protocol manages multiple independently administered fileservers to share namespace and referral information to enable clients to traverse seamlessly across them. Ellard, et al. Expires March 30, 2009 [Page 15] Internet-Draft Admin Protocol for Federated Filesystems September 2008 8. Glossary Administrator: user with the necessary authority to initiate administrative tasks on one or more servers. Admin entity: A server or agent that administers a collection of fileservers and persistently stores the namespace information. Client: Any client that accesses the fileserver data using a supported filesystem access protocol. Federation: A set of server collections and singleton servers that use a common set of interfaces and protocols in order to provide to their clients a federated namespace accessible through a filesystem access protocol. Fileserver: A server exporting a filesystem via a network filesystem access protocol. Fileset: The abstraction of a set of files and their containing directory tree. A fileset is the fundamental unit of data management in the federation. Note that all files within a fileset are descendants of one directory, and that filesets do not span filesystems. Filesystem: A self-contained unit of export for a fileserver, and the mechanism used to implement filesets. The fileset does not need to be rooted at the root of the filesystem, nor at the export point for the filesystem. A single filesystem MAY implement more than one fileset, if the client protocol and the fileserver permit this. Filesystem access protocol: A network filesystem access protocol such as NFSv2 [RFC1094], NFSv3 [RFC1813], NFSv4 [RFC3530], or CIFS. FSL (Fileset location): The location of the implementation of a fileset at a particular moment in time. A FSL MUST be something that can be translated into a protocol-specific description of a resource that a client can access directly, such as a fs_location (for NFSv4), or share name (for CIFS). Note that not all FSLs need to be explicitly exported as long as they are contained within an exported path on the fileserver. Ellard, et al. Expires March 30, 2009 [Page 16] Internet-Draft Admin Protocol for Federated Filesystems September 2008 FSN (Fileset name): A platform-independent and globally unique name for a fileset. Two FSLs that implement replicas of the same fileset MUST have the same FSN, and if a fileset is migrated from one location to another, the FSN of that fileset MUST remain the same. Junction: A filesystem object used to link a directory name in the current fileset with an object within another fileset. The server-side "link" from a leaf node in one fileset to the root of another fileset. Junction key: The UUID of a fileset, used as a key to lookup an FSN within an NSDB node or a local table of information about junctions. Namespace: A filename/directory tree that a sufficiently-authorized client can observe. NSDB (Namespace Database Service): A service that maps FSNs to FSLs. The NSDB may also be used to store other information, such as annotations for these mappings and their components. NSDB Node: The name or location of a server that implements part of the NSDB service and is responsible for keeping track of the FSLs (and related info) that implement a given partition of the FSNs. Referral: A server response to a client access that directs the client to evaluate the current object as a reference to an object at a different location (specified by an FSL) in another fileset, and possibly hosted on another fileserver. The client re-attempts the access to the object at the new location. Replica: A replica is a redundant implementation of a fileset. Each replica shares the same FSN, but has a different FSL. Replicas may be used to increase availability or performance. Updates to replicas of the same fileset MUST appear to occur in the same order, and therefore each replica is self-consistent at any moment. We do not assume that updates to each replica occur simultaneously If a replica is offline or unreachable, the other replicas may be updated. Server Collection: A set of fileservers administered as a unit. A server collection may be administered with vendor-specific software. Ellard, et al. Expires March 30, 2009 [Page 17] Internet-Draft Admin Protocol for Federated Filesystems September 2008 The namespace provided by a server collection could be part of the federated namespace. Singleton Server: A server collection containing only one server; a stand-alone fileserver. Ellard, et al. Expires March 30, 2009 [Page 18] Internet-Draft Admin Protocol for Federated Filesystems September 2008 9. Normative References [RFC1094] Nowicki, B., "NFS: Network File System Protocol specification", RFC 1094, March 1989. [RFC1813] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS Version 3 Protocol Specification", RFC 1813, June 1995. [RFC1831] Srinivasan, R., "RPC: Remote Procedure Call Protocol Specification Version 2", RFC 1831, August 1995. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3530] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame, C., Eisler, M., and D. Noveck, "Network File System (NFS) version 4 Protocol", RFC 3530, April 2003. [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2005. [RFC4506] Eisler, M., "XDR: External Data Representation Standard", STD 67, RFC 4506, May 2006. Ellard, et al. Expires March 30, 2009 [Page 19] Internet-Draft Admin Protocol for Federated Filesystems September 2008 Authors' Addresses Daniel Ellard BBN Technologies 10 Moulton Street Cambridge, MA 02138 US Phone: +1 617-873-8000 Email: ellard@gmail.com Craig Everhart NetApp 7301 Kit Creek Rd Research Triangle Park, NC 27709 US Phone: +1 919-476-5320 Email: everhart@netapp.com James Lentini NetApp 1601 Trapelo Rd, Suite 16 Waltham, MA 02451 US Phone: +1 781-768-5359 Email: jlentini@netapp.com Renu Tewari IBM Almaden 650 Harry Rd San Jose, CA 95120 US Email: tewarir@us.ibm.com Ellard, et al. Expires March 30, 2009 [Page 20] Internet-Draft Admin Protocol for Federated Filesystems September 2008 Manoj Naik IBM Almaden 650 Harry Rd San Jose, CA 95120 US Email: manoj@almaden.ibm.com Ellard, et al. Expires March 30, 2009 [Page 21] Internet-Draft Admin Protocol for Federated Filesystems September 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). Ellard, et al. Expires March 30, 2009 [Page 22]