draft-ietf-dhc-vendor-01.txt   draft-ietf-dhc-vendor-02.txt 
DHC Working Group J. Littlefield DHC Working Group J. Littlefield
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Expires: August 5, 2004 February 5, 2004 Expires: November 17, 2004 May 17, 2004
Vendor-Identifying Vendor Options for DHCPv4 Vendor-Identifying Vendor Options for DHCPv4
draft-ietf-dhc-vendor-01.txt draft-ietf-dhc-vendor-02.txt
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Abstract Abstract
The DHCP options for Vendor Class and Vendor-Specific Information can The DHCP options for Vendor Class and Vendor-Specific Information can
be ambiguous when a DHCP client represents multiple vendors. This be limiting or ambiguous when a DHCP client represents multiple
document defines two new options, modeled on the IPv6 options for vendors. This document defines two new options, modeled on the IPv6
vendor class and vendor-specific information, which contain options for vendor class and vendor-specific information, which
Enterprise Numbers to remove ambiguity. contain Enterprise Numbers to remove ambiguity.
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1]. document are to be interpreted as described in RFC 2119 [1].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Multiple Instances of Options . . . . . . . . . . . . . . . . . 3 2. Supporting Multiple Vendor Instances . . . . . . . . . . . . . 3
3. Vendor-Identifying Vendor Class Option . . . . . . . . . . . . . 3 3. Vendor-Identifying Vendor Class Option . . . . . . . . . . . . 4
4. Vendor-Identifying Vendor-Specific Information Option . . . . . 5 4. Vendor-Identifying Vendor-Specific Information Option . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1 Normative References . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . . 8 7.2 Informative References . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . 9
1. Introduction 1. Introduction
The DHCP protocol for IPv4 defines options to allow a client to The DHCP protocol for IPv4, RFC 2131 [2], defines options that allow
indicate its vendor type (option 60), and to allow the DHCP client a client to indicate its vendor type (option 60), and to allow the
and server to exchange vendor-specific information (option 43) [3]. DHCP client and server to exchange vendor-specific information
While there is no prohibition against passing multiple copies of (option 43) [5]. While there is no prohibition against passing
these options in a single packet, doing so would introduce ambiguity multiple copies of these options in a single packet, doing so would
of interpretation, particularly if conveying vendor-specific introduce ambiguity of interpretation, particularly if conveying
information for multiple vendors. The vendor identified by option 60 vendor-specific information for multiple vendors. The vendor
defines the interpretation of option 43, which itself carries no identified by option 60 defines the interpretation of option 43,
vendor identifier. which itself carries no vendor identifier. Furthermore, the
concatenation of multiple instances of the same option, required by
RFC 2131 and specified by RFC 3396 [4], means that multiple copies of
options 60 or 43 would not remain independent.
There are circumstances where an implementation may need to support There are circumstances where an implementation may need to support
multiple, independently defined forms of vendor-specific information. multiple, independently defined forms of vendor-specific information.
For example, implementations that must conform to an industry- For example, implementations that must conform to an industry-
standard use of DHCPv4, to allow interoperability in a particular standard use of DHCPv4, to allow interoperability in a particular
technology space, may be required to support the vendor-specific technology space, may be required to support the vendor-specific
options of that industry group. But the same implementation may also options of that industry group. But the same implementation may also
require support for vendor-specific options defined by the require support for vendor-specific options defined by the
manufacturer. In particular, this is an issue for vendors of devices manufacturer. In particular, this is an issue for vendors of devices
supporting CableLabs standards, such as DOCSIS, CableHome, and supporting CableLabs [9] standards, such as DOCSIS, CableHome, and
PacketCable, since those standards define an industry-specific use PacketCable, since those standards define an industry-specific use
for options 60 and 43. for options 60 and 43.
This document defines two new options, modeled on the IPv6 options This document defines two new options, modeled on the IPv6 options
for vendor class and vendor-specific information defined in RFC 3315 for vendor class and vendor-specific information defined in RFC 3315
[4], which contain Enterprise Numbers to remove ambiguity. If [6], which contain Enterprise Numbers to remove ambiguity about the
desired, these new options can be used in addition to the current interpretation of their contents. If desired, these new options can
vendor class and vendor information options, whose definition is be used in addition to the current vendor class and vendor
unaffected by this document. information options, whose definition is unaffected by this document.
2. Multiple Instances of Options 2. Supporting Multiple Vendor Instances
The options defined in this document are intended to occur multiple The options defined in this document may each contain data
times in a DHCP packet, as may be required. To provide support for corresponding to more than one vendor. The data portion of each
long option values, RFC 3396 [2] requires that all multiply instanced option defined here contains an enterprise number, followed by an
options be contatenated into one long instance. Because of this, the internal data length, followed by vendor-specific data. This
format of these new vendor options includes extra length fields to sequence may be repeated multiple times within each option. Because
allow concatenation of multiple instances, while preserving the of the possibility that the aggregate of the vendor-specific data for
integrity of each. Support for RFC 3396 is not widespread at the either option will exceed 255 octets, these options are hereby
time of this writing, so implementations SHOULD attempt to format declared to be "concatenation-requiring", as defined by RFC 3396 [4].
instances of these new vendor options such that they can be As such, the aggregate of all instances of vendor-specific data is to
interpreted without concatenation, if support for RFC 3396 is in be considered one long option, for each of the two options defined
doubt. here. These long options can be divided into smaller options for
packet encoding in conformance with RFC 3396, on whatever octet
boundaries are convenient to the implementation. Dividing on the
boundaries between vendor instances is not required, but may be
convenient for encoding or packet tracing.
3. Vendor-Identifying Vendor Class Option 3. Vendor-Identifying Vendor Class Option
A DHCP client may use this option to unambiguously identify the A DHCP client may use this option to unambiguously identify the
vendor that manufactured the hardware on which the client is running, vendor that manufactured the hardware on which the client is running,
or an industry consortium to which the vendor belongs. The the software in use, or an industry consortium to which the vendor
information contained in the data area of this option is contained in belongs. The information contained in the per-vendor data area of
one or more opaque fields that may identify details of the hardware this option is contained in one or more opaque fields that may
configuration. identify details of the hardware configuration.
This option may be used wherever Vendor Class Identifier (option 60)
may be used, as described in RFC 2131 [2], except for DHCPNAK
messages, where other options are not permitted. It is most
meaningful in messages from DHCP client to DHCP server (DHCPDISCOVER,
DHCPREQUEST, DHCPINFORM).
The format of the V-I Vendor Class option is: The format of the V-I Vendor Class option is:
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-len | | option-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| enterprise-number | | enterprise-number1 |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| data-len | | | data-len1 | |
+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+ |
/ vendor-class-data / / vendor-class-data1 /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
| enterprise-number2 | ^
option-code OPTION_V-I VENDOR_CLASS (to be assigned by IANA) | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| data-len2 | | optional
+-+-+-+-+-+-+-+-+ | |
/ vendor-class-data2 / |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ ... ~ V
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
option-code OPTION_V-I_VENDOR_CLASS (to be assigned by IANA)
option-len 5 + length of vendor class data field option-len 5 + length of vendor class data field
enterprise-number The vendor's 32-bit Enterprise Number as enterprise-numberN The vendor's 32-bit Enterprise Number as
registered with IANA [5]. registered with IANA [3]
data-len Length of vendor-class-data field data-lenN Length of vendor-class-data field
vendor-class-data Details of the hardware configuration of the host vendor-class-dataN Details of the hardware configuration of the
on which the client is running, or of industry host on which the client is running, or of
consortium compliance industry consortium compliance
Each instance of this option contains information corresponding to This option contains information corresponding to one or more
one or more Enterprise Numbers. Multiple instances of this option Enterprise Numbers. Multiple instances of this option may be
may be present, and may be concatenated in accordance with RFC 3396. present, and MUST be concatenated in accordance with RFC 3396 [4].
An Enterprise Number SHOULD only occur once among all instances of An Enterprise Number SHOULD only occur once among all instances of
this option. Behavior is undefined if an Enterprise Number occurs this option. Behavior is undefined if an Enterprise Number occurs
multiple times. The information for each Enterprise Number is multiple times. The information for each Enterprise Number is
treated independently, regardless or whether it occurs in an option treated independently, regardless or whether it occurs in an option
with other Enterprise Numbers, or in a separate option. with other Enterprise Numbers, or in a separate option.
The vendor-class-data is composed of a series of separate items, each The vendor-class-data is composed of a series of separate items, each
of which describes some characteristic of the client's hardware of which describes some characteristic of the client's hardware
configuration or capabilities. Examples of vendor-class-data configuration or capabilities. Examples of vendor-class-data
instances might include the version of the operating system the instances might include the version of the operating system the
skipping to change at page 5, line 21 skipping to change at page 5, line 46
+-+-+-+-+-+-+-+-+ opaque-data | +-+-+-+-+-+-+-+-+ opaque-data |
/ / / /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The data-len is one octet long and specifies the length of the opaque The data-len is one octet long and specifies the length of the opaque
vendor class data in network byte order. vendor class data in network byte order.
4. Vendor-Identifying Vendor-Specific Information Option 4. Vendor-Identifying Vendor-Specific Information Option
DHCP clients and servers may use this option to exchange vendor- DHCP clients and servers may use this option to exchange vendor-
specific information. specific information. Either party may send this option, as needed.
While a typical case might be for a client to send the
Vendor-Identifying Vendor Class option, to elicit a useful
Vendor-Identifying Vendor-Specific Information Option, there is no
requirement for such a flow.
This option may be used in any packets where "other" options are
allowed by RFC2131 [2], specifically DHCPDISCOVER, DHCPOFFER,
DHCPREQUEST, DHCPACK and DHCPINFORM.
The format of the V-I Vendor-specific Information option is: The format of the V-I Vendor-specific Information option is:
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-len | | option-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| enterprise-number | | enterprise-number1 |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| data-len | | | data-len1 | |
+-+-+-+-+-+-+-+-+ option-data | +-+-+-+-+-+-+-+-+ option-data1 |
/ / / /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
| enterprise-number2 | ^
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| data-len2 | | optional
+-+-+-+-+-+-+-+-+ option-data2 | |
/ / |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ ... ~ V
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
option-code OPTION_V-I VENDOR_OPTS (to be assigned by IANA) option-code OPTION_V-I_VENDOR_OPTS (to be assigned by IANA)
option-len 5 + length of option-data field option-len 5 + length of option-data field
enterprise-number The vendor's registered 32-bit Enterprise Number enterprise-numberN The vendor's registered 32-bit Enterprise Number
as registered with IANA [5]. as registered with IANA [3]
data-len Length of option-data field data-lenN Length of option-data field
option-data Vendor-specific options, described below. option-dataN Vendor-specific options, described below.
The definition of the information carried in this option is vendor The definition of the information carried in this option is vendor
specific. The vendor is indicated in the enterprise-number field. specific. The vendor is indicated in the enterprise-number field.
Each instance of this option contains information corresponding to This option contains information corresponding to one or more
one or more Enterprise Numbers. Multiple instances of this option Enterprise Numbers. Multiple instances of this option may be
may be present, and may be concatenated in accordance with RFC 3396. present, and MUST be concatenated in accordance with RFC 3396 [4].
An Enterprise Numbers SHOULD only occur once among all instances of An Enterprise Number SHOULD only occur once among all instances of
this option. Behavior is undefined if an Enterprise Number occurs this option. Behavior is undefined if an Enterprise Number occurs
multiple times. The information for each Enterprise Number is multiple times. The information for each Enterprise Number is
treated independently, regardless or whether it occurs in an option treated independently, regardless or whether it occurs in an option
with other Enterprise Numbers, or in a separate option. with other Enterprise Numbers, or in a separate option.
Use of vendor-specific information allows enhanced operation, Use of vendor-specific information allows enhanced operation,
utilizing additional features in a vendor's DHCP implementation. utilizing additional features in a vendor's DHCP implementation.
Servers not equipped to interpret the vendor-specific information Servers not equipped to interpret the vendor-specific information
sent by a client MUST ignore it. Clients that do not receive desired sent by a client MUST ignore it. Clients that do not receive desired
vendor-specific information SHOULD make an attempt to operate without vendor-specific information SHOULD make an attempt to operate without
it. it.
The encapsulated vendor-specific options field MUST be encoded as a The encapsulated vendor-specific option-data field MUST be encoded as
sequence of code/length/value fields of identical format to the DHCP a sequence of code/length/value fields of identical format to the
options field. The option codes are defined by the vendor identified DHCP options field. The option codes are defined by the vendor
in the enterprise-number field and are not managed by IANA. Option identified in the enterprise-number field and are not managed by
codes 0 and 255 have no pre-defined interpretation or format. Each IANA. Option codes 0 and 255 have no pre-defined interpretation or
of the encapsulated options is formatted as follows: format. Each of the encapsulated options is formatted as follows:
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subopt-code | subopt-len | | subopt-code | subopt-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ sub-option-data / / sub-option-data /
/ / / /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
subopt-code The code for the encapsulated option subopt-code The code for the encapsulated option
subopt-len An unsigned integer giving the length of the subopt-len An unsigned integer giving the length of the
option-data field in this encapsulated option in option-data field in this encapsulated option in
octets. octets
sub-option-data Data area for the encapsulated option sub-option-data Data area for the encapsulated option
5. IANA Considerations 5. IANA Considerations
The values for the V-I VENDOR CLASS and V-I VENDOR OPTS option codes The values for the OPTION_V-I_VENDOR_CLASS and OPTION_V-I_VENDOR_OPTS
must be assigned from the numbering space defined for public DHCP option codes must be assigned from the numbering space defined for
Options in RFC 2939 [6]. public DHCP Options in RFC 2939 [7].
6. Security Considerations 6. Security Considerations
This document in and by itself provides no security, nor does it This document in and by itself provides no security, nor does it
impact existing security. DHCP provides an authentication and impact existing security. DHCP provides an authentication and
message integrity mechanism, as described in RFC 3118 [7], which may message integrity mechanism, as described in RFC 3118 [8], which may
be used if authenticity is required for data carried by the options be used if authenticity is required for data carried by the options
defined in this document. defined in this document.
References 7. References
7.1 Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Lemon, T. and S. Chesire, "Encoding Long Options in the Dynamic [2] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
March 1997.
[3] IANA, "Private Enterprise Numbers",
<http://www.iana.org/assignments/enterprise-numbers.html>.
[4] Lemon, T. and S. Chesire, "Encoding Long Options in the Dynamic
Host Configuration Protocol (DHCPv4)", RFC 3396, November 2002. Host Configuration Protocol (DHCPv4)", RFC 3396, November 2002.
[3] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor 7.2 Informative References
[5] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997. Extensions", RFC 2132, March 1997.
[4] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. [6] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M.
Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 3315, July 2003. RFC 3315, July 2003.
[5] IANA, "Private Enterprise Numbers", <http://www.iana.org/ [7] Droms, R., "Procedures and IANA Guidelines for Definition of New
assignments/enterprise-numbers.html>.
[6] Droms, R., "Procedures and IANA Guidelines for Definition of New
DHCP Options and Message Types", BCP 43, RFC 2939, September DHCP Options and Message Types", BCP 43, RFC 2939, September
2000. 2000.
[7] Droms, R. and W. Arbaugh, "Authentication for DHCP Message", RFC [8] Droms, R. and W. Arbaugh, "Authentication for DHCP Message", RFC
3118, June 2001. 3118, June 2001.
URIs
[9] <http://www.cablelabs.com/>
Author's Address Author's Address
Josh Littlefield Josh Littlefield
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978-936-1379 Phone: +1 978-936-1379
EMail: joshl@cisco.com EMail: joshl@cisco.com
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