Internet DRAFT - draft-ietf-svrloc-IPv6
draft-ietf-svrloc-IPv6
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Internet Engineering Task Force John Veizades
INTERNET DRAFT @Home Network
11 July 1996 Erik Guttman
Expires in six months Sun Microsystems
Service Location Modifications for IPv6
draft-ietf-svrloc-IPv6-00.txt
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
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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
administration.
The Service Location Protocol is well defined for use over IPv4
networks [SLP]: This document defines its use over IPv6 networks.
Since this protocol relies on UDP and TCP, the changes to support its
use over IPv6 are minor.
1.0 Protocol Changes
The following are changes required to have the Service Location
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Internet Draft Service Location Modifications for IPv6 11 July 1996
Protocol work over IPv6. These changes include:
2.0 Eliminating support for broadcast SLP requests
3.0 Restricted Propogation of Link Local Addresses
4.0 Address Specification for IPv6 Addresses in URLs
5.0 Changes to DHCP options
2.0 Eliminating support for broadcast SLP requests
Service Location over IPv4 allows broadcasts to send Service Location
request messages. This is no longer supported. If a User Agent
wishes to make a request to discover Directory Agents or make a
request of multiple Service Agents, the User Agent must multicast the
request to the appropriate multicast address.
This change modifies the requirements described in Section 4.6 (Use
of TCP, UDP and Multicast in Service Location) and Section 22
(Implementation Requirements) of the Service Location Protocol [SLP].
The General Service Location Multicast address and the Directory
Agent Discovery Multicast address have been assigned for IPv4, but
have not yet been assigned for IPv6. This will be done as soon as
possible.
3.0 Restricted Propogation of Link Local Addresses
A Service Agent may send a Service Registration to a Directory Agent
using its Link Local address. This may occur in an environment where
there is no DNS [DNS] or router available. If DNS is available, the
Service Agent SHOULD register a FQDN. If DNS is present, then, this
would not be an issue. If a router is available, the Service Agent
may register a routable address.
A Directory Agent must not propogate this Service Registration
information to User Agents that request it from other links. This
means that Directory Agents must inspect the URL registered by a
Service Agent in a Service Registration message and ascertain whether
the address included is a numerical IPv6 address which specifies a
link local address. In this case, it must be returned to User Agent
Service Requests only if the User Agent is on the same link as the
link local address of the Service URL.
This constitutes an additional requirement for Directory Agents and
modifies the list given in [SLP], Section 22 (Implementation
Requirements).
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Internet Draft Service Location Modifications for IPv6 11 July 1996
4.0 Address Specification for IPv6 Addresses in URLs
Service Location allows the use of the protocol without the benefit
of DNS. This is relevant when a group of systems is connected to
build a network without any previous configuration of servers to
support this network. When Service Location is used in this manner,
addresses must be used to identify end systems. Systems must
explicitely provide their numerical addresses in this case.
The address specification for IPv6 replaces the address specification
description for the "dotted decimal IP address notation" in section
21.4 of the Service Location Protocol [SLP].
The form is a string representation of the hexadecimal values of the
eight 16-bit pieces of the address [AddrSpec].
The colons in the address must be escaped for the purposes of
inclusion in a URL [URL]. The IPv6 address represented in a URL will
take the following form:
Examples:
FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
becomes:
FEDC%3aBA98%3a7654%3a3210%3aFEDC%3aBA98%3a7654%3a3210
To add a port number (say 3431) to this address specification, a
colon followed by the port number value may be appended, as
follows:
FEDC%3aBA98%3a7654%3a3210%3aFEDC%3aBA98%3a7654%3a3210:3431
The port number value after the colon is expressed in decimal
notation, as defined in [URL].
When ever possible the DNS name of the service should be used rather
than the above representation.
5.0 Changes to DHCP Options
The DHCP options for use in Service Location have been submitted to
the IANA and DHCP working group of the IETF for standardization. One
of these option returns the IPv4 address of the Directory Agent for a
host to use. This option will have to be changed for IPv6 so that the
Directory Agent address will be 128 bits wide. This new option
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Internet Draft Service Location Modifications for IPv6 11 July 1996
definition will be submitted in a formal proposal in the near future.
See [DHCPv6 EXT].
6.0 Security Considerations
Security issues are not discussed in this document.
7.0 References
[DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC1541,
October 1993
[SLP] Veizades, J., Guttman, E., Perkins, C., Kaplan, S., "Service
Location Protocol", Work in progress, June 1996
[DNS] Mockapetris, P. V. "Domain names - concepts and facilities",
RFC 1034. November 1987.
Mockapetris, P. V. "Domain names - implementation and
specification", RFC 1035. November 1987.
[URL] Berners-Lee, T., Masinter, L., McCahill, M., "Uniform Resource
Locators (URL)", RFC 1738, December 1994
[AddrSpec] Hinden, R., Deering, S., "IP Version 6 Addressing
Architecture", RFC 1884, January 1996
[DHCPV6-EXT] Perkins, C., "Extensions for DHCPv6", Work in progress,
June 1996.
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Internet Draft Service Location Modifications for IPv6 11 July 1996
8. Author Information
John Veizades
@Home Network
385 Ravendale Dr.
Mountain View, CA 94043
Phone: +1 415 944 7332
Fax: +1 415 944 8500
Email: veizades@home.net
Erik Guttman
Sun Microsystems
2550 Garcia Avenue, MS PAL01-550
Mountain View, CA 94043-1100
Phone: +1 415 336 6697
Fax: +1 415 336 0673
Email: Erik.Guttman@eng.sun.com
9.0 This document expires January 16, 1997.
Veizades, Guttman [Page 5]
