draft-ietf-dhc-fqdn-opt-00.txt		draft-ietf-dhc-fqdn-opt-01.txt
	Network Working Group Yakov Rekhter, Cisco Systems		Network Working Group Yakov Rekhter, Cisco Systems
	Internet Draft Ralph Droms, Bucknell University		INTERNET DRAFT Ralph Droms, Bucknell University
	Expiration Date: August 1996 February 1996		Obsoletes: draft-ietf-dhc-fqdn-opt-00.txt April 1996
			Expires October 1996
	FQDN DHCP Option		An option for FQDNs in DHCP options
	draft-ietf-dhc-fqdn-opt-00.txt		<draft-ietf-dhc-fqdn-opt-01.txt>
	1. Status of this Memo		Status of this Memo
	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 any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		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 the
	``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow		``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow
	Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),		Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
	munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or		munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
	ftp.isi.edu (US West Coast).		ftp.isi.edu (US West Coast).
	2. Abstract		Abstract
	DHCP [DHCP] can be used to automate the process of configuring TCP/IP		DHCP [DHCP] can be used to automate the process of configuring TCP/IP
	host computers. However, some of the DHCP options carry IP addresses		host computers. However, some of the DHCP options carry IP addresses
	rather than Fully Qualified Domain Names (FQDN). Use of IP addresses		rather than Fully Qualified Domain Names (FQDN). Use of IP addresses
	constrains the DHCP client to use the addresses that were in use at		constrains the DHCP client to use the addresses that were in use at
	the time the client received its configuration information; these		the time the client received its configuration information; these
	addresses may change over time, (e.g., a server may be assigned a new		addresses may change over time, (e.g., a server may be assigned a new
	IP address), so that the IP addresses used by the client may become		IP address), so that the IP addresses used by the client may become
	invalid.		invalid.
	An alternative to passing IP addresses is to pass FQDNs instead of		An alternative to passing IP addresses is to pass FQDNs instead of
	(numeric) IP addresses. Doing this allows to defer binding between a		(numeric) IP addresses. Doing this allows to defer binding between a
	particular network entity (e.g., a server) and its IP address until		particular network entity (e.g., a server) and its IP address until
	run time. As stated in [Carpenter:95], "Deferring the binding avoids		run time. As stated in [Carpenter:95], "Deferring the binding avoids
	the risk of changed mapping between IP addresses and specific network		the risk of changed mapping between IP addresses and specific network
	entities (due to changing addressing information). Moreover,		entities (due to changing addressing information). Moreover,
	reliance on FQDNs (rather than IP addresses) also localizes to the		reliance on FQDNs (rather than IP addresses) also localizes to the
	DNS the changes needed to deal with changing addressing information		DNS the changes needed to deal with changing addressing information
	due to renumbering."		due to renumbering."
			DRAFT An option for FQDNs in DHCP options April 1996
	This document defines a new DHCP option that allows the use of FQDNs		This document defines a new DHCP option that allows the use of FQDNs
	instead of IP addresses in DHCP options.		instead of IP addresses in DHCP options.
	3. Definitions		Definitions
	The following defines the format of the FQDN option.		The following defines the format of the FQDN option.
	+----------+----------+		+----------+----------+
	| Code | Length |		| Code | Length |
	+----------+----------+---------+-----------+--------------------		+----------+----------+---------+-----------+--------------------
	|Subcode |Sublength | FQDN		|Subcode |Sublength | FQDN
	+----------+----------+---------+-----------+--------------------		+----------+----------+---------+-----------+--------------------
	..................		..................
	skipping to change at page 3, line 6		skipping to change at page 3, line 5
	FQDN carried in the option. The FQDN field carries the FQDN itself.		FQDN carried in the option. The FQDN field carries the FQDN itself.
	More that one triple with a given subcode may appear within a single		More that one triple with a given subcode may appear within a single
	FQDN option. Options that can carry a list of IP addresses should be		FQDN option. Options that can carry a list of IP addresses should be
	coded as multiple subcodes in the FQDN option, to differentiate among		coded as multiple subcodes in the FQDN option, to differentiate among
	the variable-length FQDNs.		the variable-length FQDNs.
	This option only allows the use of FQDNs for options that have been		This option only allows the use of FQDNs for options that have been
	elsewhere defined to carry IP addresses.		elsewhere defined to carry IP addresses.
	4. Example		DRAFT An option for FQDNs in DHCP options April 1996
			Example
	The following illustrates how the FQDN option could be used to carry		The following illustrates how the FQDN option could be used to carry
	FQDNs for 2 LPR Servers with FQDNs lpr1.xxx.org and lpr2.yy.org, and		FQDNs for 2 LPR Servers with FQDNs lpr1.xxx.org and lpr2.yy.org, and
	one Network Information Server with FQDN nis.zzzz.org.		one Network Information Server with FQDN nis.zzzz.org.
	+---+---+		+---+---+
	|xx |41 |		|xx |41 |
	+---+---+---+---+---+---+---+---+---+---+---+---+---+---+		+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	|41 |12 | n | i | s | . | z | z | z | z | . | o | r | g |		|41 |12 | n | i | s | . | z | z | z | z | . | o | r | g |
	+---+---+---+---+---+---+---+---+---+---+---+---+---+---+		+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	| 9 |12 | l | p | r | 1 | . | x | x | x | . | o | r | g |		| 9 |12 | l | p | r | 1 | . | x | x | x | . | o | r | g |
	+---+---+---+---+---+---+---+---+---+---+---+---+---+---+		+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
	| 9 |11 | l | p | r | 2 | . | y | y | . | o | r | g |		| 9 |11 | l | p | r | 2 | . | y | y | . | o | r | g |
	+---+---+---+---+---+---+---+---+---+---+---+---+---+		+---+---+---+---+---+---+---+---+---+---+---+---+---+
	5. Security Considerations		Security Considerations
	Security issues are not discussed in this document.		Security issues are not discussed in this document.
	6. References		References
	[Carpenter:95] Carpenter, B., Rekhter, Y., "Renumbering considered		[Carpenter:95] Carpenter, B., Rekhter, Y., "Renumbering considered
	unavoidable", Internet Draft		unavoidable", Internet Draft
	[DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC1541,		[DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC1541,
	October 1993		October 1993
	7. Acknowledgements		Acknowledgements
	To be supplied.		To be supplied.
	8. Author Information		DRAFT An option for FQDNs in DHCP options April 1996
			Author Information
	Yakov Rekhter		Yakov Rekhter
	cisco Systems, Inc.		cisco Systems, Inc.
	170 Tasman Dr.		170 Tasman Dr.
	San Jose, CA 95134		San Jose, CA 95134
	Phone: (914) 528-0090		Phone: (914) 528-0090
	email: yakov@cisco.com		email: yakov@cisco.com
	Ralph Droms		Ralph Droms
	Computer Science Department		Computer Science Department
End of changes.
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