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DNS SRV Resource Records for AFS
RFC 5864

Document type: RFC - Proposed Standard (April 2010; Errata)
Updates RFC 1183
Was draft-allbery-afs-srv-records (individual in app area)
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

IETF State: (None)
Consensus: Unknown
Document shepherd: No shepherd assigned

IESG State: RFC 5864 (Proposed Standard)
Responsible AD: Alexey Melnikov
Send notices to: rra@stanford.edu, jhutz@cmu.edu

Internet Engineering Task Force (IETF)                        R. Allbery
Request for Comments: 5864                           Stanford University
Updates: 1183                                                 April 2010
Category: Standards Track
ISSN: 2070-1721

                    DNS SRV Resource Records for AFS

Abstract

   This document specifies how to use DNS (Domain Name Service) SRV RRs
   (Resource Records) to locate services for the AFS distributed file
   system and how the priority and weight values of the SRV RR should be
   interpreted in the server ranking system used by AFS.  It updates RFC
   1183 to deprecate the use of the AFSDB RR to locate AFS cell database
   servers and provides guidance for backward compatibility.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5864.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Allbery                      Standards Track                    [Page 1]
RFC 5864                   DNS SRV RRs for AFS                April 2010

Table of Contents

   1. Overview and Rationale ..........................................2
   2. Scope ...........................................................3
   3. Requirements Notation ...........................................3
   4. DNS SRV RRs for AFS .............................................4
      4.1. Interpretation as AFS Preference Ranks .....................5
   5. Use of AFSDB RRs ................................................6
   6. Example .........................................................8
   7. Security Considerations .........................................9
   8. References ......................................................9
      8.1. Normative References .......................................9
      8.2. Informative References ....................................10

1.  Overview and Rationale

   AFS (a registered trademark of IBM Corporation) is a distributed file
   system (see [AFS1] and [AFS2]).  Its most widely used implementations
   are [OPENAFS] and [ARLA].

   AFS is organized administratively into cells.  Each AFS cell consists
   of one or more Volume Location Database (VLDB) servers, one or more
   Protection Service (PTS) servers, and one or more file servers and
   volume servers, plus possible additional services not relevant to
   this document.  Data stored in AFS is divided into collections of
   files called volumes.  An AFS protocol client, when accessing a file
   within a specific AFS cell, first contacts a VLDB server for that
   cell to determine the file server for the AFS volume in which that
   file is located, and then contacts that file server directly to
   access the file.  A client may also need to contact a PTS server for
   that cell to register before accessing files in that cell or to query
   protection database information.

   An AFS client therefore needs to determine, for a given AFS cell, the
   VLDB and possibly the PTS servers for that cell.  (Traditionally, the
   VLDB and PTS servers are provided by the same host.)  Once the client
   is in contact with the VLDB server, it locates file and volume
   servers through AFS protocol queries to the VLDB server.  Originally,
   VLDB server information was configured separately on each client in a
   file called the CellServDB file.  [RFC1183] specified the DNS RR
   (Resource Record) AFSDB to locate VLDB servers for AFS.

   Subsequent to [RFC1183], a general DNS RR was defined by [RFC2782]
   for service location for any service.  This DNS SRV RR has several
   advantages over the AFSDB RR:

Allbery                      Standards Track                    [Page 2]

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