INTERNET-DRAFT K. Luehrs
Dynamic Host Configuration Working Group CableLabs
Expires June 2003 R. Woundy
AT&T Broadband
J. Bevilacqua
YAS Corporation
December 2002
KDC Server Address Sub-option
<draft-ietf-dhc-suboptions-kdc-serveraddress-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.
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Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This document defines a new sub-option for the CableLabs Client
Configuration (CCC) DHCP option code for conveying the network
addresses of Key Distribution Center (KDC) servers.
1. Introduction
The need for a CCC DHCP Option code is described in [1]. The CCC
DHCP option code will be used to address specific needs of CableLabs
client devices during their configuration processes. This document
proposes a sub-option for the CCC DHCP option.
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Configuration of a class of CableLabs client devices described in
[2] requires a DHCP sub-option to provide the client with the
network address of a KDC server in the cable operator's data
network. The class of devices assumed in [2] is unlike the class
of devices considered in [1], which perform a DNS lookup of the
Kerberos Realm name to find the KDC server network address.
This document proposes a sub-option of the CCC DHCP option
code for use with CableLabs client devices. The proposed sub-option
encodes an identifier for the network address of each of one or more
Key Distribution Center servers with which the CableLabs client
device exchanges security information.
CableLabs plans to assign sub-option code ranges for the CCC option
according to CableLabs projects. The range (51 - 100) is assigned
to the CableHome project. Use of the initial value of this range is
specified in [2].
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT" and "MAY"
in this document are to be interpreted as described in RFC 2119 [3].
2. Key Distribution Center IP Address Sub-option
The CableHome 1.0 specification [2] specifies the Key Distribution
Center network address encoding as a sub-option of the CCC DHCP
Option code. This field is used to inform the client device of the
network address of one or more Key Distribution Center servers.
The encoding of the KDC Server Address sub-option will adhere to the
format of an IPv4 address using the default port. The minimum length
for this option is 4 octets, and the length MUST always be a
multiple of 4. If multiple KDC Servers are listed, they MUST be
listed in decreasing order of priority. The format of the KDC Server
Address sub-option of the CCC option code is as shown below:
SubOpt Len Address 1 Address 2
+------+-----+-----+-----+-----+-----+-----+-----+--
| 51 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+------+-----+-----+-----+-----+-----+-----+-----+--
3. Security Considerations
This document relies upon the DHCP protocol [4] for authentication
and security, i.e., it does not provide security in excess of what
DHCP is (or will be) providing. It does not expose any security
threats beyond what is currently exposed by other DHCP options.
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Internet Draft KDC Server Address Sub-option December 2002
4. IANA Considerations
The KDC Server Address sub-option described in this document is
intended to be a sub-option of the CableLabs Client Configuration
(CCC) option described in [1]. IANA will be requested to register
sub-option code 51 of the CCC option to the KDC Server Address
sub-option.
5. Normative References
[1] "DHCP Option for CableLabs Client Configuration draft-ietf-dhc-
packetcable-05", IETF, December 2002.
[2] "CableHome 1.0 Specification SP-CH1.0-I02-020920", CableLabs,
September 2002, http://www.cablelabs.com/projects/cablehome/
specifications/.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[4] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March
1997.
6. Authors' Addresses
Kevin Luehrs
CableLabs
400 Centennial Parkway
Louisville, CO 80027
Phone: (303) 661-9100
EMail: k.luehrs@cablelabs.com
Richard Woundy
AT&T Broadband
27 Industrial Drive
Chelmsford, MA 01824
Phone: (978) 244-4010
EMail: rwoundy@broadband.att.com
John Bevilacqua
YAS Corporation
300 Brickstone Square
Andover, MA 01810
Phone: (978) 749-9999
EMail: john@yas.com
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Internet Draft KDC Server Address Sub-option December 2002
7. Full Copyright Statement
Copyright (C) The Internet Society (2002). 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
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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 develop-
ing 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
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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.
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