draft-ietf-dhc-slp-00.txt		draft-ietf-dhc-slp-01.txt
	Internet Engineering Task Force C. Perkins		Internet Engineering Task Force C. Perkins
	INTERNET DRAFT IBM		INTERNET DRAFT IBM
	27 August 1996		14 March 1997
	DHCP Options for Service Location Protocol		DHCP Options for Service Location Protocol
	draft-ietf-dhc-slp-00.txt		draft-ietf-dhc-slp-01.txt
	Status of This Memo		Status of This Memo
	This document is a submission to the Dynamic Host Configuration		This document is a submission to the Dynamic Host Configuration
	Working Group of the Internet Engineering Task Force (IETF). Comments		Working Group of the Internet Engineering Task Force (IETF). Comments
	should be submitted to the dhcp@bucknell.edu mailing list.		should be submitted to the dhcp@bucknell.edu mailing list.
	Distribution of this memo is unlimited.		Distribution of this memo is unlimited.
	This document is an Internet-Draft. Internet-Drafts are working		This document is an Internet-Draft. Internet-Drafts are working
	documents of the Internet Engineering Task Force (IETF), its areas,		documents of the Internet Engineering Task Force (IETF), its areas,
	and its working groups. Note that other groups may also distribute		and its working groups. Note that other groups may also distribute
	working documents as Internet-Drafts.		working documents as Internet-Drafts.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at		and may be updated, replaced, or obsoleted by other documents at
	any time. It is inappropriate to use Internet- Drafts as reference		any time. It is inappropriate to use Internet- Drafts as reference
	material or to cite them other than as ``work in progress.''		material or to cite them other than as ``work in progress.''
	To learn the current status of any Internet-Draft, please check the		To learn the current status of any Internet-Draft, please check
	``1id-abstracts.txt'' listing contained in the Internet- Drafts		the ``1id-abstracts.txt'' listing contained in the Internet-Drafts
	Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),		Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (North
	munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or		Europe), ftp.nis.garr.it (South Europe), munnari.oz.au (Pacific Rim),
	ftp.isi.edu (US West Coast).		ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast).
	Abstract		Abstract
	The Dynamic Host Configuration Protocol provides a framework for		The Dynamic Host Configuration Protocol provides a framework for
	passing configuration information to hosts on a TCP/IP network.		passing configuration information to hosts on a TCP/IP network.
	Entities using the Service Location Protocol need to find out the		Entities using the Service Location Protocol need to find out the
	address of Directory Agents in order to transact messages. In		address of Directory Agents in order to transact messages. In
	certain other instances they may need to discover the correct scope		certain other instances they may need to discover the correct scope
	and naming authority to be used in conjunction with the service		to be used in conjunction with the service attributes and URLS which
	attributes and URLS which are exchanged using the Service Location		are exchanged using the Service Location Protocol.
	Protocol.
	1. Directory Agent Extension		1. Introduction
	This extension specifies a Directory Agent (DA) [3], along with zero		The Dynamic Host Configuration Protocol [2] provides a framework
	or more Naming Authorities [2] known to that DA and zero or more		for passing configuration information to hosts on a TCP/IP network.
	scopes supported by that DA.		Entities using the Service Location Protocol [3] need to find out
			the address of Directory Agents in order to transact messages. In
			certain other instances they may need to discover the correct scope
			to be used in conjunction with the service attributes and URLs [1]
			which are exchanged using the Service Location Protocol.
	The code for this extension is 78. Each Naming Authority and each		The scope MAY be denoted in any standardized character set. Values
	scope MUST be a null-terminated string of ASCII characters. The		for character encoding can be found in IANA's database
	lengths of the strings are only indicated implicitly by their null		http://www.isi.edu/in-notes/iana/assignments/character-sets
	termination and the overall length of the extension.		and have the values referred by the MIBEnum value.
			Note that each option listed below may be included multiple times in
			the same DHCPOFFER or DHCPREQUEST. If so, then the options SHOULD be
			included in order of decreasing preference.
			2. Directory Agent Option
			This option requests or specifies a Directory Agent (DA), along with
			zero or more scopes supported by that DA.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Code | Length |D| NA count | scope count |		| Code | Length |D|S| reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| (if present) |
	| Directory Agent address (16 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| NA list ...		| (if present) Directory Agent address |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| scope list ...		| Char Encoding | scope ...
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Code 78		Code 78
	Length variable		Length variable
	D If the 'D' bit is set, the Directory Agent address is		D If the 'D' bit is set, the Directory Agent address is
	present.		present.
	NA count		S If the 'S' bit is set, the scope is present, encoded in
	The number of Naming Authorities indicated by strings in		the indicated character set.
	the NA list following.
	scope count
	The number of scopes indicated by strings in the scope
	list following.
	NA list		Char Encoding
	A list of strings denoting Naming Authorities.		The standardized encoding for the characters making up
			the string denoting the scope.
	scope list		scope A string denoting the scope.
	A list of strings denoting scopes.
	Note that more than one Directory Agent extension may be present in		Note that more than one Directory Agent option may be present in a
	a DHCP message. Each such extension may have the same or different		DHCP message. Each such option may have the same or different scope.
	lists of Naming Authorities and scopes. The client may request a		The client may request any Directory Agent with a particular scope,
	Directory Agent with a particular scope, and/or knowledgeable about		by including the Directory Agent option in a DHCP Request message
	schemes defined by a particular Naming Authority, by including the		with no Directory Agent address included (the 'D' bit set to zero),
	Directory Agent extension in a DHCP Request message with no Directory		and the string denoting the scope. The length of the scope string is
	Agent address included (the 'D' bit set to zero), and the appropriate		only indicated implicitly by the overall length of the option.
	strings in the NA list and/or scope list.
	2. Service Scope Extension		3. Service Scope Option
	This extension indicates a scope that should be used by a Service		This option indicates a scope that should be used by a Service Agent
	Agent (SA) [3], when responding to Service Request messages as		(SA) [3], when responding to Service Request messages as specified by
	specified by the Service Location Protocol.		the Service Location Protocol.
	Code Len		0 1 2 3
	+-----+-----+-----+-----		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	| 79 | n | Scope ...		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	+-----+-----+-----+-----		| Code | Length | Char Encoding |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| scope ...
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Scope is a null-terminated ASCII string, of length 'n' including the		Code 79
	terminating null character.
	3. Naming Authority Extension		Length variable
	This extension indicates a naming authority (which specifies the		Char Encoding
	syntax for schemes that may be used in URLs [1]) for use by entities		The standardized encoding for the characters making up
	with the Service Location Protocol.		the string denoting the scope.
	Code Len		scope A string denoting the scope.
	+-----+-----+-----+-----+-----+-----
	| 80 | n | Naming Authority ...
	+-----+-----+-----+-----+-----+-----
	Naming Authority is a null-terminated ASCII string, of length 'n'		Note that more than one Service Scope option may be present in a DHCP
	including the terminating null character.		message. The length of the scope string is only indicated implicitly
			by the overall length of the option.
	4. Security Considerations		4. Security Considerations
	If a malicious host is able to insert fraudulent information in		If a malicious host is able to insert fraudulent information in
	DHCPOFFER packets sent to a prospective client of the Service		DHCPOFFER packets sent to a prospective client of the Service
	Location Protocol, then the client will be unable to obtain service,		Location Protocol, then the client will be unable to obtain service,
	and vulnerable to disclosing information to unauthorized service		and vulnerable to disclosing information to unauthorized service
	agents. Likewise, a service agent would find that it might rely on		agents. Likewise, a service agent would find that it might rely on
	fraudulent or otherwise malicious directory agents to advertise its		fraudulent or otherwise malicious directory agents to advertise its
	services. Many opportunities for denial of service exist.		services. Many opportunities for denial of service exist.
	skipping to change at page 3, line 20		skipping to change at page 3, line 22
	5. Acknowledgements		5. Acknowledgements
	Thanks to Erik Guttman for his helpful suggestions in the creation of		Thanks to Erik Guttman for his helpful suggestions in the creation of
	this draft.		this draft.
	References		References
	[1] T. Berners-Lee, L. Masinter, and M. McCahill. Uniform Resource		[1] T. Berners-Lee, L. Masinter, and M. McCahill. Uniform Resource
	Locators (URL). RFC 1738, December 1994.		Locators (URL). RFC 1738, December 1994.
	[2] Paul E. Hoffman and Ron Daniel, Jr. Generic URN Syntax.		[2] Ralph Droms. Dynamic Host Configuration Protocol. RFC 1541,
	draft-ietf-uri-urn-syntax-00.txt -- work in progress, April 1995.		October 1993.
	[3] J. Veizades, E. Guttman, C. Perkins, and S. Kaplan. Service		[3] J. Veizades, E. Guttman, C. Perkins, and S. Kaplan. Service
	Location Protocol. draft-ietf-svrloc-protocol-14.txt - work in		Location Protocol, November 1996. draft-ietf-svrloc-protocol-15.txt
	progress, June 1996.		(work in progress).
	Author's Address		Author's Address
	Questions about this memo can be directed to:		Questions about this memo can be directed to:
	Charles Perkins		Charles E. Perkins
	Room J1-A25		Sun Microsystems
	T. J. Watson Research Center		2550 Garcia Avenue
	IBM Corporation		Mountain View, CA 94043
	30 Saw Mill River Rd.
	Hawthorne, NY 10532
	Work: +1 914 7847350		Phone: +1 415 336 7153
	Fax: +1 914 7847007		Fax: +1 415 336 0670
	E-mail: perk@watson.ibm.com
			EMail: charliep@acm.org
End of changes.
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