Network Working Group V. Devarapalli
Request for Comments: 5096 Azaire Networks
Category: Standards Track December 2007
Mobile IPv6 Experimental Messages
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract
This document defines a new experimental Mobility Header message and
a Mobility option that can be used for experimental extensions to the
Mobile IPv6 protocol.
Table of Contents
1. Introduction ....................................................1
2. Terminology .....................................................2
3. Experimental Mobility Header Message ............................3
4. Experimental Mobility Option ....................................3
5. Security Considerations .........................................4
6. IANA Considerations .............................................5
7. Acknowledgements ................................................5
8. References ......................................................5
8.1. Normative References .......................................5
8.2. Informative References .....................................5
1. Introduction
When experimenting with a protocol or defining a new extension to a
protocol, one needs either a protocol number, a new message, or an
option to carry the information related to the experiment. Most
implementations end up using unassigned values for the new messages.
Many times this creates problems when the same value is assigned
through the IETF standards action, by IANA, or if the implementation
gets deployed with these messages. Therefore, it is considered a
good practice to set aside some code points that identify the
experimental protocols or messages for experimental purposes. The
need for experimental messages is shown in [3].
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RFC 5096 MIPv6 Experimental Messages December 2007
This document defines new messages for experimenting with extensions
to the Mobile IPv6 protocol. These messages should be strictly used
for experiments. Experiments that are successful should be
standardized in the IETF. An implementation MUST NOT be released or
deployed with the experimental messages.
This document defines a new Mobility Header message, which is the
Experimental Mobility message that can be sent at any time by the
mobile node, the home agent or the correspondent node. Since
Mobility Header messages cannot be combined and sent in one packet,
there is always only one Mobility Header message in any Mobile IPv6
packet. Home agent or correspondent node implementations that do not
recognize the mobility message type, discard the message and send a
Binding Error message as described in [2], with the Status field set
to 2 (unrecognized MH Type value). Mobile nodes that do not
recognize the mobility message type should discard the message and
send an ICMP Parameter problem with code 0.
This document also defines a new mobility option, the Experimental
Mobility option, which can be carried in any Mobility Header message.
Mobility options, by definition, can be skipped if an implementation
does not recognize the mobility option type [2].
The messages defined in this document can also be used for Network
Mobility (NEMO) [4] and Proxy Mobile IPv6 [5] since these protocols
also use Mobility Header messages.
Experimental code points could potentially disrupt a deployed network
when experiments using these code points are performed in the
network. Therefore, the network scope of support for experimental
values should carefully be evaluated before deploying any experiment
across extended network domains, such as the public Internet.
Experimental mechanisms should only be used for actual
experimentation. By design, only a single code point is allocated
for the message and another one for the option. This limits the
number of experiments among a set of peers to one at a time. When
experimental mechanisms are shown to be useful, and there is a desire
to deploy them beyond the experiment they should be standardized and
given new code points.
2. Terminology
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 [1].
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RFC 5096 MIPv6 Experimental Messages December 2007
3. Experimental Mobility Header Message
The Experimental Mobility Header message is based on the Mobility
Header message defined in Section 6.1 of RFC 3775 [2]. There are no
fields in the message beyond the required fields in the Mobility
Header. The 'MH Type' field in the Mobility Header indicates that it
is an Experimental Mobility Header message.
If no data is present in the message, two bytes of padding are
required. The 'Header Len' field in the Mobility Header is set to 0
since the first 8 octets are excluded while calculating the length of
the Mobility Header message.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Proto | Header Len | MH Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
. .
. Message Data .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
See RFC 3775 [2] for a description of the 'Payload Proto', 'Header
Len', 'MH Type', 'Reserved', and 'Checksum' fields.
The 'Message Data' field carries the data specific to the
experimental protocol extension. The total length of the message is
indicated by the 'Header Len' field in the Mobility Header.
4. Experimental Mobility Option
The Experimental Mobility option can be included in any Mobility
Header message. If the Mobility Header message includes a Binding
Authorization Data option [2], then the Experimental Mobility option
should appear before the Binding Authorization Data option.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Data .....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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RFC 5096 MIPv6 Experimental Messages December 2007
Type
An 8-bit field indicating that it is an experimental mobility
option.
Length
An 8-bit field indicating the length of the option in octets
excluding the Type and Length fields.
Data
Data related to the experimental protocol extension.
5. Security Considerations
Protection for the Experimental Mobility Header message and Mobility
option depends on the experiment that is being carried out and the
kind of information that is being carried in the messages. If these
messages carry information that should not be revealed on the wire,
or that can affect the binding cache entry at the home agent or the
correspondent node, they should be protected in a manner similar to
Binding Updates and Binding Acknowledgements.
Security analyzers such as firewalls and network intrusion detection
monitors often rely on unambiguous interpretations of the fields
described in this document. As new values for the fields are
assigned, existing security analyzers that do not understand the new
values may fail, resulting in either loss of connectivity, if the
analyzer declines to forward the unrecognized traffic, or in loss of
security if it does forward the traffic and the new values are used
as part of an attack.
When experimental code points are deployed within an administratively
self-contained network domain, it must be ensured that each code
point is used consistently to avoid interference between experiments.
When experimental code points are used in traffic that crosses
multiple administrative domains, the experimenters should assume that
there is a risk that the same code points will be used simultaneously
by other experiments and that there is a possibility that the
experiments will interfere. Particular attention should be given to
security threats that such interference might create. Please see RFC
4727 for more details [6].
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RFC 5096 MIPv6 Experimental Messages December 2007
6. IANA Considerations
The Experimental Mobility Header message, defined in Section 3, has
been assigned the type value (11), allocated from the same space as
the 'MH Type' field in the Mobility Header [2].
The Experimental Mobility option, defined in Section 4, has been
assigned the type value (18), allocated from the same space as
Mobility Options [2].
7. Acknowledgements
The author would like to thank Jari Arkko and Basavaraj Patil with
whom the contents of this document were discussed first.
8. References
8.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
IPv6", RFC 3775, June 2004.
8.2. Informative References
[3] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004.
[4] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert,
"Network Mobility (NEMO) Basic Support Protocol", RFC 3963,
January 2005.
[5] Gundavelli, S., "Proxy Mobile IPv6", Work in Progress, March
2007.
[6] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, ICMPv6,
UDP, and TCP Headers", RFC 4727, November 2006.
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RFC 5096 MIPv6 Experimental Messages December 2007
Author's Address
Vijay Devarapalli
Azaire Networks
4800 Great America Pkwy
Santa Clara, CA 95054
USA
EMail:
[email protected]
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RFC 5096 MIPv6 Experimental Messages December 2007
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Devarapalli Standards Track [Page 7]
