One document matched: draft-templin-isatap-dhcp-03.txt
Differences from draft-templin-isatap-dhcp-02.txt
Network Working Group F. Templin
Internet-Draft Boeing Research & Technology
Intended status: Informational November 23, 2009
Expires: May 27, 2010
Dynamic Host Configuration Protocol (DHCPv4) Option for the Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)
draft-templin-isatap-dhcp-03.txt
Abstract
This document specifies a Dynamic Host Configuration Protocol
(DHCPv4) option for nodes that implement the Intra-Site Automatic
Tunnel Addressing Protocol (ISATAP).
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 27, 2010.
Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
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described in the BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Requirements . . . . . . . . . . . . . . . . . 3
3. ISATAP DHCPv4 Option . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
5. Related Work . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
This document specifies a Dynamic Host Configuration Protocol option
[RFC2131][RFC2132] for the Intra-Site Automatic Tunnel Addressing
Protocol (ISATAP) [RFC5214]. The option encodes configuration
information used by clients to initialize the Potential Router List
(PRL) as specified in [RFC5214], section 8.3.2. The option format is
similar to [RFC3361] and supports publishing of an IPv4 anycast
address followed by a list of IPv4 addresses and/or domain names that
form the PRL for the ISATAP link.
2. Terminology and Requirements
The terminology of ISATAP [RFC5214] applies to this document.
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in [RFC2119].
3. ISATAP DHCPv4 Option
The ISATAP DHCPv4 option encodes an ISATAP IPv4 Anycast address
followed by a list of 'M' 4-octet IPv4 addresses followed by a list
of 'N' DNS [RFC1035] fully-qualified domain names (FQDNs). The
ISATAP DHCPv4 option encodes a sequence of octets using the following
format:
Code Len M N Any <- IPv4 addr's -> <- FQDN's ->
+----+----+----+-----+----+----+----+----+----+----+----+----+----+
| TBD| Len| M | N | Any| a1 | a2 | ...| aM | f1 | f2 | ...| fN |
+----+----+----+-----+----+----+----+----+----+----+----+----+----+
Figure 1
In this format, the DHCPv4 option code is followed immediately by a
'Len' octet that indicates the total number of octets that follow
within this DHCPv4 option field. The rest of the DHCPv4 option is
encoded as follows:
o the 'Len' octet is followed immediately by an 'M' octet that
indicates the total number of IPv4 addresses that follow the IPv4
Anycast address,
o the 'M' octet is followed immediately by an 'N' octet that
indicates the total number of FQDNs that follow the list of IPv4
addresses,
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o the 'N' octet is followed by a 4-octet IPv4 Anycast address,
o the IPv4 Anycast address is followed by a list of 'M' 4-octet IPv4
addresses,
o the list of IPv4 addresses if followed by a list of 'N' DNS FQDN's
encoded exactly as specified in Section 3.1 of [RFC1035]. (Note:
this is the same format specified in Section 3.1 of [RFC1035]).
For example, if the server wants to advertise the IPv4 anycast
address '192.0.2.1', followed by the IPv4 addresses '192.0.2.3' and
'192.0.2.3', followed by the FQDNs "isatap.com", "isatap.org" and
"isatap.net", the DHCPv4 option would be encoded as follows (where
numeric values are represented as decimal):
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|TBD| 51| 2 | 3 |192| 00| 02| 01|192| 00| 02| 02|192| 00| 02|
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| 03| 0 | 6 |'i'|'s'|'a'|'t'|'a'|'p'| 3 |'c'|'o'|'m'| 0 | 6 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|'i'|'s'|'a'|'t'|'a'|'p'| 3 |'o'|'r'|'g'| 0 | 6 |'i'|'s'|'a'|
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|'t'|'a'|'p'| 3 |'n'|'e'|'t'| 0 |
+---+---+---+---+---+---+---+---+
Figure 2
ISATAP clients MAY use the elements encoded in the ISATAP DHCPv4
option to initialize the PRL as specified in Section 8.3.2 of
[RFC5214]. Legacy ISATAP clients may instead silently ignore this
option and continue to use their pre-existing PRL initialization
methods, i.e., backward compatibility is preserved.
Note: when no IPv4 anycast address is to be used for this ISATAP
link, the IPv4 Anycast address is encoded as four zero octets (i.e.,
to represent the value '0.0.0.0'). When a non-zero IPv4 anycast
address is included, ISATAP clients MAY use this address as the IPv4
destination address of ip-proto-41 packets that were forwarded into
the ISATAP interface via an IPv6 default route. ISATAP routers do
not use the IPv4 anycast address as the source address for
ip-proto-41 packets; they use their IPv4 unicast address that is
listed in the ISATAP PRL instead. This implies that each ISATAP
router MUST configure both the IPv4 Anycast address (when the anycast
address is non-zero) and an IPv4 unicast address that is added to the
PRL.
When the length of the ISATAP DHCPv4 Option exceeds 254 octets, the
option is encoded as for DHCP long options as specified in [RFC3396].
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ISATAP routers and clients use the unicast IPv4 address in the PRL
(i.e., and not the ISATAP IPv4 anycast address) for IPv6 neighbor
discovery operations the same as specified in Section 8 of [RFC5214].
4. IANA Considerations
A new DHCPv4 option number for ISATAP is requested.
5. Related Work
The ISATAP DHCP option was published in
'draft-templin-isatap-dhcp-00.tx' in February 2003. The use of IPv4
Anycast with ISATAP was published in
'draft-ietf-ngrtans-isatap-00.txt' in March 2001.
'draft-ietf-softwire-ipv6-6rd' presents a similar DHCP option that
advertises a 6RD prefix and an IPv4 anycast address.
6. Security Considerations
The security considerations in [RFC2131] apply.
7. Acknowledgments
The following individuals are acknowledged for their contributions:
Jim Bound, Ralph Droms, Mohan Parthasarathy, Pekka Savola.
8. References
8.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, March 1997.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
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[RFC3396] Lemon, T. and S. Cheshire, "Encoding Long Options in the
Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396,
November 2002.
[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214,
March 2008.
8.2. Informative References
[RFC3361] Schulzrinne, H., "Dynamic Host Configuration Protocol
(DHCP-for-IPv4) Option for Session Initiation Protocol
(SIP) Servers", RFC 3361, August 2002.
Author's Address
Fred L. Templin
Boeing Research & Technology
P.O. Box 3707
Seattle, WA 98124
USA
Email: fltemplin@acm.org
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