Service Location Protocol
RFC 2165

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 16

Network Working Group                                       J. Veizades
Request for Comments: 2165                                @Home Network
Category: Standards Track                                    E. Guttman
                                                             C. Perkins
                                                       Sun Microsystems
                                                              S. Kaplan
                                                              June 1997

                       Service Location Protocol

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   The Service Location Protocol provides a scalable framework for the
   discovery and selection of network services.  Using this protocol,
   computers using the Internet no longer need so much static
   configuration of network services for network based applications.
   This is especially important as computers become more portable, and
   users less tolerant or able to fulfill the demands of network system
   administration.

Table of Contents

 1. Introduction                                                       3
 2. Terminology                                                        3
     2.1. Notation Conventions  . . . . . . . . . . . . . . . . . .    5
     2.2. Service Information and Predicate Representation  . . . .    5
     2.3. Specification Language  . . . . . . . . . . . . . . . . .    6
 3. Protocol Overview                                                  6
     3.1. Protocol Transactions . . . . . . . . . . . . . . . . . .    7
     3.2. Schemes . . . . . . . . . . . . . . . . . . . . . . . . .    8
           3.2.1. The "service:" URL scheme . . . . . . . . . . . .    9
     3.3. Standard Attribute Definitions  . . . . . . . . . . . . .    9
     3.4. Naming Authority  . . . . . . . . . . . . . . . . . . . .   10
     3.5. Interpretation of Service Location Replies  . . . . . . .   10
     3.6. Use of TCP, UDP and Multicast in Service Location . . . .   10
           3.6.1. Multicast vs.  Broadcast  . . . . . . . . . . . .   11
           3.6.2. Service-Specific Multicast Address  . . . . . . .   11
     3.7. Service Location Scaling, and Multicast Operating Modes .   12

Veizades, et. al.           Standards Track                     [Page 1]
RFC 2165               Service Location Protocol               June 1997

 4. Service Location General Message Format                           14
     4.1. Use of Transaction IDs (XIDs) . . . . . . . . . . . . . .   15
     4.2. URL Entries . . . . . . . . . . . . . . . . . . . . . . .   16
     4.3. Authentication Blocks . . . . . . . . . . . . . . . . . .   17
     4.4. URL Entry Lifetime  . . . . . . . . . . . . . . . . . . .   19
 5. Service Request Message Format                                    19
     5.1. Service Request Usage . . . . . . . . . . . . . . . . . .   22
     5.2. Directory Agent Discovery Request . . . . . . . . . . . .   23
     5.3. Explanation of Terms of Predicate Grammar . . . . . . . .   24
     5.4. Service Request Predicate Grammar . . . . . . . . . . . .   26
     5.5. String Matching for Requests  . . . . . . . . . . . . . .   27
 6. Service Reply Message Format                                      28
 7. Service Type Request Message Format                               29
 8. Service Type Reply Message Format                                 31
 9. Service Registration Message Format                               32
10. Service Acknowledgement Message Format                            35
11. Service Deregister Message Format                                 37
12. Attribute Request Message Format                                  38
13. Attribute Reply Message Format                                    40
14. Directory Agent Advertisement Message Format                      42
15. Directory Agents                                                  43
    15.1. Introduction  . . . . . . . . . . . . . . . . . . . . . .   43
    15.2. Finding Directory Agents  . . . . . . . . . . . . . . . .   43
16. Scope Discovery and Use                                           45
    16.1. Protected Scopes  . . . . . . . . . . . . . . . . . . . .   46
17. Language and Character Encoding Issues                            47
    17.1. Character Encoding and String Issues  . . . . . . . . . .   48
          17.1.1. Substitution of Character Escape Sequences  . . .   49
    17.2. Language-Independent Strings  . . . . . . . . . . . . . .   49
18. Service Location Transactions                                     50
    18.1. Service Location Connections  . . . . . . . . . . . . . .   50
    18.2. No Synchronous Assumption . . . . . . . . . . . . . . . .   51