draft-ietf-dhc-option-review-and-namespace-02.txt   draft-ietf-dhc-option-review-and-namespace-03.txt 
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Network Working Group Michael Carney
Dynamic Host Configuration Working Group Sun Microsystems, Inc
New Option Review Guidelines and Additional Option Namespace
<draft-ietf-dhc-option-review-and-namespace-02.txt>
Status of this memo
This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
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documents at any time. It is inappropriate to use Internet-
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"work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
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Comments regarding this draft should be sent to dhcp-v4@bucknell.edu
Abstract
This document outlines deficiencies that have become evident since
RFC 2131 and RFC 2132 were published regarding the allocation of
new option codes, the review of drafts covering these new option
codes, and the availability of option codes for new parameters. The
document then presents proposals for correcting these deficiencies.
1. Introduction
The rapid and wide-spread adoption of DHCPv4 has lead to an
increasing number of new DHCP option and message type drafts under
DHC WG review. Experience with the current IANA option code
allocation process and the DHC WG draft review process has
identified a number of deficiencies, namely:
* We're rapidly going through the remaining option codes, and face
the possibility of exhausting the remaining codes before the
wide-spread adoption of IPv6 is achieved.
* There are no guidelines to help the DHC WG and the DHCP
community at large gauge the impact of the addition of new
message types and options. Some message types and options that
have been proposed require changes to the DHCP protocol itself
and/or current implementations. Because the adoption of such
message types or options has a greater impact on the DHCP
community, these message types and options require more
scrutiny by the DHC WG and IESG.
* Because some options or message types could change the DHCP
protocol itself, we need a method of explicitly communicating
the change of DHCP versions among implementations. Today, we
have no such method.
* There is no provision to preserve compatibility with earlier
versions of the protocol.
Interoperability testing at Connectathon (1997, 1998, and 1999)
has shown a reduction in the level of interoperability between
implementations. These interoperability problems were found to
be due to confusion among implementors about how certain features
of the protocol should be implemented. Improvement (tightening)
of the general RFC 2131 and RFC 2132 drafts as well as the
tightening of new option specifications (using the guidelines
defined in this document) will help increase the level of
interoperability.
1.1 Conventions Used in the Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [5].
1.2 Terminology
RFC 2132-form options The RFC 2132 [2] option block form is
currently in use by DHCPv4, and is
documented in RFC 2131 [1]. This option
form is identified by the BOOTP magic
cookie {99, 130, 83, 99}.
RFC TBD-form options A new option block form recommendation
to alleviate option code exhaustion
(described in section 3.6 below). This
option form will be identified by a TBD
BOOTP magic cookie issued by IANA.
2. Review Guidelines
We tackle the message type and option code review problem by
defining a set of categories based upon upon the impact the
adoption of an option or new message type will have on the DHCP
community. Option or new message drafts appropriately categorized
aid reviewers by helping them evaluate the draft. Once the DHC WG
and the draft author(s) agree on the category of the proposed
option or message type, that category will be listed explicitly
in the abstract of the option or message draft.
2.1. Hints for selecting the correct review category
A) This option has no relationship to other existing or proposed
options. It would not require change of existing DHCP client,
server, or BOOTP relay agent implementations. It would not
change the version of the DHCP protocol. Its introduction
would not invalidate previous version(s) of the DHCP
protocol. Is this option better handled by the Service Location
Protocol (SLP) [7]? If it provides data which is unrelated
to network interface configuration, then the option proposer
SHOULD consider the use of SLP for the delivery of this data,
if SLP is deployed widely enough to meet her needs.
B) This message type has no relationship to other existing or
proposed message types. It would not require change of
existing DHCP client, server, or BOOTP relay agent
implementations. It would not change the version of the DHCP
protocol. The message type is useful to the DHCP community at
large.
C) This option has no relationship to other existing or
proposed options or message types. It would not require
change of existing DHCP client, server, or BOOTP relay
agent implementations. It would not change the version of the
DHCP protocol. Its introduction would not invalidate previous
version(s) of the DHCP protocol. It isn't a candidate for SLP.
Is this option useful to the DHCP community at large (e.g.
implementors) or is it specific to a particular
implementation? If it is the latter, then the proposer of
the option should consider using the encapsulated vendor space
available to your implementation to encode this information.
Note that most DHCP implementations only support default
option types for encapsulated options. (see Section 3.6 below).
D) This option has no relationship to other existing or
proposed options or message types. It would not require change
of existing DHCP client, server, or BOOTP relay agent
implementations. It would not change the version of the DHCP
protocol. Its introduction would not invalidate previous
version(s) of the DHCP protocol. It is not a candidate for
SLP or the vendor's option space. Can this option be
effectively encoded in the default option type (Section 3.6
below)? For example, can it be communicated as a single
ASCII string? A list of IP addresses? If so, then one of the
default formats should be used.
E) This option would have a implicit or explicit relationship
between it and other existing options or other proposed
options, or the data it represents cannot be carried in a
default option type (Section 3.6 below). It MAY change the
behavior of existing DHCP client, server, and/or BOOTP relay
agent implementations. It would not change the DHCP protocol
version. Its introduction would not invalidate previous
version(s) of the DHCP protocol.
Examples of implicit/explicit option relationships:
Option Related Options
------ ---------------
Vendor Class Identifier Encapsulated vendor option(s)
User Class Identifier Standard option's scope
F) This message type would have a implicit or explicit
relationship between it and other existing message types or
options Its adoption MAY change the behavior of existing DHCP
client, server, and/or BOOTP relay agent implementations. It
would not change the DHCP protocol version. Its introduction
would not invalidate previous version(s) of the DHCP protocol.
G) The addition of this option would change Table 3, "Fields and
options used by DHCP servers" and/or Table 5, "Fields and
options used by DHCP clients" in RFC 2131 [1], and thus
change the DHCP protocol. Pre-existing versions /
implementations would continue to interoperate.
H) The addition of this option or message type would invalidate
previous versions of the DHCP protocol, preventing client,
server, and/or BOOTP relay agents implementing the earlier
version(s) from functioning.
Guidelines Review Category
---------- ---------------
A None. Use SLP to register and
deliver your information.
B Category One
C None. Use your Vendor-specific
option space for your option.
D Category One
E Category Two
F Category Two
G Category Three
H Category Four
2.2. Category One
Options in this category MUST NOT require changes to the DHCP
protocol, server, client, or BOOTP relay agent implementations.
They MAY be either RFC 2132-form or RFC TBD-form options. They MUST
NOT be dependent on other options being present or absent. Earlier
versions/implementations of the protocol continue to interoperate
in the presence of these options. Administrative tools and DHCP
protocol debugging tools which generically support the default
option types MAY need to be reconfigured in order to permit
management of the new option. Options of this type are "payload"
options, and MUST be of one of the default option types for the
option block form (RFC 2132 or RFC TBD).
Acceptance criteria:
Working group/IETF community review: Yes.
IANA option number registration: Yes.
Interoperability testing (2 or more implementations) No.
DHCP protocol version change: No.
2.3. Category Two
Options in this category MUST NOT require changes to the DHCP
protocol. They MAY require changes to server, client, relay agent
implementations, administrative tools, and DHCP protocol debugging
tools. They MAY depend on the presence or absence of other options,
as long as those other options are NOT in Table 3 or Table 5 of
RFC 2131 [1]. Any dependence on other options MUST be made
explicit in the new options draft. Existing versions /
implementations of the protocol continue to interoperate in the
presence of messages containing category two options. Options of
this type are "affect implementation" options.
An option MUST be designed in such a way as a reply/response from
non-compliant implementations can be easily distinguished from
those of compliant implementations. An option MUST NEVER change the
interpretation of existing options. The option draft author MUST
specify a compliant implementation's behavior if that implement-
ation receives a reply/response from a non-compliant implementation.
Acceptance criteria:
Working group/IETF community review: Yes.
IANA option number registration: Yes.
Interoperability testing (2 or more implementations) Yes.
DHCP protocol version change: No.
2.4. Category Three
Options in this category EXPLICITLY change the DHCP protocol. They
WILL require changes to server, client, and/or relay agent
implementations. They MAY depend on the presence or absence of
other options. Any dependence on other options MUST be made
explicit in the new option draft. The addition of such options
result in changes to Table 3, "Fields and options used by DHCP
servers" and/or Table 5, "Fields and options used by DHCP clients"
in RFC 2131 [1]. Existing versions / implementations of the
protocol continue to interoperate in the presence of traffic
containing category three options. Administrative tools MUST be
changed to support options of this type. DHCP protocol debugging
tools would need to be updated to recognize these options. Options
of this type are known as "affect protocol" options. The acceptance
of a Category Three option results in incrementing the DHCP version
option value.
An option MUST be designed in such a way as a reply/response from
non-compliant implementations can be easily distinguished from
those of compliant implementations. The option draft author MUST
specify a compliant implementation's behavior if that implement-
ation receives a reply/response from a non-compliant
implementation. An option MUST NEVER change the interpretation of
existing options. Category Three option implementations can easily
detect a non-compliant implementation due to the absence of the
DHCP version option or a lower than expected version number.
Acceptance criteria:
Working group/IETF community review: Yes.
IANA option number registration: Yes.
Interoperability testing (2 or more implementations) Yes.
DHCP protocol version change: Yes.
2.5. Category Four
Options in this category would EXPLICITLY change the DHCP
protocol in a non-backward compatible manner. They would require
changes to ALL DHCP client, server, and/or BOOTP relay agent
implementations. They INVALIDATE one or more of the previous
versions of the BOOTP/DHCP protocol.
Because category four options invalidate previous versions of the
protocol, they are NOT candidates for acceptance. Changes to the
the DHCP protocol MUST BE backward compatible.
3. New RFC 2132-form options for version, block-type, and parameter
request list.
We define three new RFC 2132-form options. The first is used by
a DHCP client to request a response in a certain option block form.
The second option is used by both DHCP clients and servers to
explicitly identify the version of protocol used in the messages
generated. The final option is used by RFC TBD client
implementations to request RFC TBD options from RFC TBD servers.
3.1. DHCP Option Block Request Option
This option is used by RFC TBD client implementations to request
RFC TBD-form replies from RFC TBD server implementations. This
option is included in RFC 2132-form DHCPDISCOVERs, INIT-REBOOT
DHCPREQUESTs, and DHCPINFORMs to request RFC TBD-form replies.
This option MUST NOT be used by DHCP servers in their responses
to DHCP clients.
The DHCP Option Block Request Option is of the RFC 2132-form, and
consists of a single 4 octet string holding the magic cookie of
the desired option block form.
Code Len Magic cookie
+-----+-----+----------------+
| X | 4 | ... |
+-----+-----+----------------+
3.2. DHCP Version Option
This option represents the DHCP version. DHCP messages without
this option are RFC 2131 [1]. The addition of Category Three
option(s) (perhaps grouped together) result in a DHCP version
change. All implementations supporting versions greater than RFC
2131 MUST include the DHCP version option in all messages,
generated by both client or server.
The DHCP Protocol Version Option is of the RFC 2132-form, and
consists of an single unsigned 16bit integer. The first Category
Three option accepted by the DHC WG will be assigned version zero
(0).
Code Len Value
+-----+-----+---------+
| Y | 2 |(0-65535)|
+-----+-----+---------+
DHCP protocol versions MUST be backward compatible with earlier
versions.
3.3. RFC TBD Parameter Request List Option
This option is used by a RFC TBD DHCP client to request values for
the specified configuration parameters. The list of requested
parameters is specified as a power of 2n octets, where each 16 bit
field carries an unsigned 16bit number from 1-65534 representing
valid DHCP option codes defined in RFC 2132 [2] and in separate
option specification drafts. Note that at most 128 options can be
requested.
The client MAY list the options in order of preference. The DHCP
server is not required to return the options in the requested
order.
The RFC TBD parameter request list option is intended for use by
RFC TBD DHCP clients and servers ONLY. While a RFC TBD client
could include use either (or both) parameter request list options
(RFC 2132 code 55 or this option), such a client SHOULD make
request its parameters using only the RFC TBD parameter request
list option.
Code Len Option Codes
+-----+-----+-----+-----+-----+-----+---
| Z | 2n | s1 | s2 | ...
+-----+-----+-----+-----+-----+-----+---
3.4 Allocation of options from RFC 2132 or RFC TBD option name spaces
Allocation of new options from the RFC TBD name space can only
occur if we have two (2) or more RFC TBD option name space
implementations which have demonstrated interoperability. Such
interoperability testing could occur at the next Connectathon
event (held late February/early March every year).
The selection of which name space from which to allocate an option
is left to the DHC WG and IESG, following the process outlined in
Ralph Drom's "Procedure for Defining New DHCP Options" [4].
3.5. RFC 2132 Option Block Form
For convenience, I have extracted the description of RFC 2132-form
options from RFC 2132 [2].
Code Len Value
+-----+-----+-------
| | | ...
+-----+-----+-------
Options of this form consist of three single octet fields: code,
len, and value.
The code value is a single octet (0-255). 0 (pad) and 255 (end)
are the only codes that do not follow the code, len, value form.
Len is a single octet (0-255) describing the length of the value
field. Value contains the data payload.
3.6. RFC 2132-form Default Option Types
1) Single variable-length ASCII string.
2) Single variable-length OCTET string.
3) 1-X Multiple of NUMBERs (1, 2, 4, 8 octets each). May consist of
a LIST where the list entries are defined as multiple NUMBERs.
Example: "A variable-length list of 2 32bit NUMBERs
representing the offset and length of a
block of data"
4) 1-X Multiple of IPv4 addresses. May consist of a LIST where the
list entries consist of multiple IP addresses.
Example: "A list of static routes (destination, router), ..."
If an implementation encounters RFC 2132-form options which it does
not understand, it will simply skip over the option (using that
option's len field) and continue option processing. This behavior
ensures that RFC 2131 compliant implementations safely ignore new
options (e.g. the DHCP version option). Current DHCP
implementations SHOULD ignore any non-RFC 2132-form option block.
3.7. Proposed RFC TBD Option Block Form
We propose the creation of the following option block form
described below, which greatly increases the option space and size
of individual options. We feel that the adoption of this option
block form will resolve the approaching RFC 2132 standard option
code availability problem.
Code Len Data
+---------+---------+------------------
| uint16_t| uint16_t| ...
+---------+---------+------------------
Code value is a network-order double-octet unsigned value (0-
65535). 0 (pad) and 65535 (end) are the only codes that do not
follow the code, len, value form. Len is a network-order
double-octet unsigned value (0-65535). Data contains Len octets.
The first 255 RFC TBD option codes are preassigned for mapping
RFC 2132 options into the RFC TBD option space. Because the size
limit of options within the RFC TBD option space is much higher
than that of options within the RFC 2132 option space, RFC TBD
server implementations MUST use care in responding to RFC 2132
clients. If the data for a mapped RFC 2132 option would exceed the
253 length restriction of RFC 2132 clients, the RFC TBD
implementation MUST drop the option from the reply, and SHOULD
increment an error count or log a message regarding this event.
Note that the creation of multiple instances of RFC 2132 options
in order to provide all of the data within the configured RFC TBD
option is not workable, since by definition options within the
RFC 2132 (and RFC TBD) option space are position-independent, and
thus deterministic ordering of data is not possible.
3.8. RFC TBD Default Option Types
All option types as listed in Section 3.6, and:
1) UNICODE string.
2) IPv6 addresses(s). Multiple of 16 octets. Encoded within an
implementation's configuration table using the text
representation as defined by Section 2.2 of RFC 2373 [6].
3) Encapsulated RFC TBD options. For example, New User class,
Vendor class-style options. Encapsulated options follow same
code, len, value form of RFC TBD options. Overall length
specifies limit of encapsulation.
4) Mixed-type options. These options are made up of combinations
of 3.6/3.8 typed fields. Variable-length typed fields are
preceded by a two octet unsigned integer length field. Mixed
type options are useful for encoding combinations of data
(structures).
Example: The following option contains an NVT ASCII string
followed by a boolean, followed by a 32bit unsigned integer.
Code Len Data
+-------+-------+-------+-------------+---+---------------+
| 771 | 17 | 13 |Hello, World!| 1 | 4123782 |
+-------+-------+-------+-------------+---+---------------+
5) BOOLEAN. A single octet value which is explicitly TRUE if
non-zero, explicitly FALSE if zero (0). Len is always one.
4. Behavior of RFC 2132 and RFC TBD Client and Server Implementations
4.1 Client Behavior
A DHCP client in the INIT state prefers DHCP replies matching the
DHCP option block form (RFC 2132 or RFC TBD) and DHCP protocol
version of its DHCPDISCOVER. Option block form is preferred over
DHCP protocol version.
DHCP clients SHOULD always indicate the size of response they
can accept using the DHCP MTU option.
4.1.1 INIT/INFORM states
A client in one of these states pauses to collect replies (DHCP
of any type/version or BOOTP replies) for a tunable polling
interval (default: 5 seconds). Retransmissions use the algorithm
outlined in Section 4.1 of RFC 2131 [1].
Existing RFC 2132-form clients require no change in their behavior
as specified in RFC 2131 [1].
RFC 2132-form clients who support a later version of the DHCP
protocol include the DHCP version option identifying the version of
DHCP protocol they support. They prefer replies matching their
protocol version over older versions of DHCP and BOOTP replies. If
a RFC 2132-form client selects a reply from a down-rev DHCP protocol
server (or BOOTP server), then that client MAY update an error count
or log this event.
A RFC TBD-form client in one of these states forms the appropriate
RFC 2132-form message (DHCPDISCOVER, DHCPINFORM) and includes the
DHCP Option Block Request Option (set to the RFC TBD magic cookie)
and the DHCP version option if it supports a version greater than
that specified in RFC 2131, and sends this message in the manner
appropriate for the message type. A RFC TBD-form client
prefers RFC TBD-form responses over RFC 2132-form responses. Within
responses of a certain option form, responses which match the
client's DHCP protocol version are preferred over those responses
that are down-rev. If no DHCP responses are received, the client
MAY choose a BOOTP response if such a response is available. A RFC
TBD-form client MAY use the RFC TBD parameter request option to
request options in the RFC TBD option space (section 3.3).
In the case of an INIT state client, the DHCPREQUEST used to accept
the DHCPOFFER is formed using the option block form and DHCP
protocol version of the selected DHCPOFFER.
For the duration of the lease, the client MUST form request messages
using the option block form and DHCP protocol version of the
original DHCPACK (INIT/INFORM) states when verifying existing
configuration (INIT-REBOOT DHCPREQUEST), requesting lease
extensions (DHCPREQUEST), declining an IP address (DHCPDECLINE),
or releasing an IP address (DHCPRELEASE).
In summary, a RFC TBD-form DHCP client will prefer RFC TBD-form
replies over RFC 2132-form replies. Within replies which match the
selected option block form, a client will prefer replies which match
its DHCP protocol version. All subsequent traffic is done using the
option block form and DHCP protocol version of the accepted
DHCPOFFER/DHCPACK.
4.2 Server Behavior
4.2.1 Option Block Format-independent Server Behavior
A server which receives a BOOTP magic cookie it does not understand
SHOULD respond with a standard BOOTP reply ONLY if it is explicitly
configured to do so. Note that RFC TBD-form requests will appear to
RFC 2131 servers as BOOTP requests with an unrecognized magic
cookie. In such environments, the RFC 2131 server's ability to
respond to BOOTP clients SHOULD be restricted, and RFC TBD servers
SHOULD be configured to respond to BOOTP clients.
If a DHCPDISCOVER/DHCPINFORM is received which contains a DHCP
protocol version option, a server MUST:
a) If the DHCP protocol version is down-rev of that supported by
the server, the server will format all messages in that
earlier version. If the DHCP server does not support the
earlier version of the protocol, it MUST drop the request,
and MAY update an error counter or log the event.
b) If the DHCP protocol version is greater than that supported
by the server, it MAY either drop the request or respond to
the client using messages of the DHCP protocol version
supported by the server. This behavior SHOULD be configurable
by the administrator. The server SHOULD choose to delay
responding to the up-rev client for a configurable number of
seconds, in order to give potential higher-rev servers a
chance to reply.
c) If the DHCP protocol version matches that of the server, then
the server responds immediately (if possible) to the client
with the appropriately formatted reply.
4.2.2 RFC TBD-form Server Behavior
A RFC TBD-form server can identify a RFC TBD-form client by the
presence of the DHCP Option Block Request Option with the RFC TBD
magic cookie in the option value field in RFC 2132-form requests
or RFC TBD-form requests identified by the RFC TBD-form magic
cookie. For the following scenarios, assume a RFC TBD-form server
has free resources available for allocation.
a) If a RFC TBD-form response is requested, it MUST respond with
a RFC TBD-form response if it chooses to respond at all. The
server SHOULD endeavor to provide the information requested
in any present RFC 2132 code 55 (parameter request list
option) and/or RFC TBD parameter request list option (Section
3.3).
b) If a RFC 2132-form response is requested (no DHCP Option Block
Request Option is present) and the RFC TBD-form server is
explicitly configured to respond to RFC 2132-form clients, it
MUST respond with a RFC 2132-form response if it chooses to
respond at all.
c) If a request is received which contains a DHCP Option Block
Request Option with a value it does not recognize, the server
MUST either drop the request or respond with a RFC 2132-form
response. Its behavior in this situation SHOULD be an
administrator-configured option.
A DHCP server MUST NOT use the DHCP Option Block Request Option in
the messages it generates for DHCP clients.
5. Security Considerations
Not Applicable.
6. Acknowledgements
The author would like to gratefully acknowledge the active
participation of the following DHCP future panel members:
Ralph Droms, Kester Fong, Pratik Gupta, Barr Hibbs, Kim Kinnear,
Ted Lemon, Nathan Lane, and Glenn Waters. The author would also
like to thank Thomas Narten for his review comments.
7. Copyright
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
8. References
[1] Droms, R. "Dynamic Host Configuration Protocol", RFC 2131,
Bucknell University, March 1997.
<ftp://ds.internic.net/rfc/rfc2131.txt>
[2] Alexander, S. and Droms, R., "DHCP Options and BOOTP
Vendor Extension", RFC 2132, March 1997.
<ftp://ds.internic.net/rfc/rfc2132.txt>
[3] Prindeville, P. "BOOTP Vendor Information Extensions", RFC 1048,
McGill University, February 1988.
<ftp://ds.internic.net/rfc/rfc1048.txt>
[4] Droms, R. "Procedure for Defining New DHCP Options",
<ftp://www.ietf.org/internet-drafts/draft-ietf-dhc-new-options-02.txt>
[5] Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, Harvard University, March 1997.
<ftp://ds.internic.net/rfc/rfc2119.txt>
[6] Hinden R. and Deering, S., "IP Version 6 Addressing
Architecture", RFC 2373, Nokia and Cisco Systems, July 1998.
<ftp://ds.internic.net/rfc/rfc2373.txt>
[7] Guttman E., Perkins C., Veizades J., and Day M., "Service
Location Protocol, Version 2", April 1999.
<ftp://www.ietf.org/internet-drafts/draft-ietf-svrloc-protocol-v2-16.txt>
9. Author's Address
Michael Carney
Sun Microsystems, Inc.
901 San Antonio Road
Palo Alto, CA 94303-4900
Phone: (650) 786-4171
Fax: (650) 786-5896
Email: Michael.Carney@sun.com
10. Expiration
This document will expire on September 30, 2000.
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