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IETF RFC 6745
Last modified on Saturday, November 10th, 2012
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Internet Research Task Force (IRTF) RJ Atkinson
Request for Comments: 6745 Consultant
Category: Experimental SN Bhatti
ISSN: 2070-1721 U. St Andrews
November 2012
ICMP Locator Update Message for the
Identifier-Locator Network Protocol for IPv4 (ILNPv4)
 Abstract
This note defines an experimental ICMP message type for IPv4 used
with the Identifier-Locator Network Protocol (ILNP). ILNP is an
experimental, evolutionary enhancement to IP. The ICMP message
defined herein is used to dynamically update Identifier/Locator
bindings for an existing ILNP session. This is a product of the IRTF
Routing Research Group.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This document is a product of the Internet Research Task
Force (IRTF). The IRTF publishes the results of Internet-related
research and development activities. These results might not be
suitable for deployment. This RFC represents the individual
opinion(s) of one or more members of the Routing Research Group of
the Internet Research Task Force (IRTF). Documents approved for
publication by the IRSG are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/RFC 6745.
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RFC 6745 ILNPv4 ICMP November 2012
Copyright Notice
Copyright (c) 2012 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
This document may not be modified, and derivative works of it may not
be created, except to format it for publication as an RFC or to
translate it into languages other than English.
Table of Contents
1. Introduction ....................................................2
1.1. Document Roadmap ...........................................3
1.2. ICMPv4 Locator Update ......................................4
1.3. Terminology ................................................5
2. ICMP Locator Update Message for ILNPv4 ..........................5
3. Transport Protocol Effects ......................................8
4. Implementation Considerations ...................................8
5. Backwards Compatibility .........................................9
6. Security Considerations .........................................9
7. IANA Considerations ............................................10
8. References .....................................................10
8.1. Normative References ......................................10
8.2. Informative References ....................................11
9. Acknowledgements ...............................................11
1. Introduction
This document is part of the ILNP document set, which has had
extensive review within the IRTF Routing RG. ILNP is one of the
recommendations made by the RG Chairs. Separately, various refereed
research papers on ILNP have also been published during this decade.
So the ideas contained herein have had much broader review than the
IRTF Routing RG. The views in this document were considered
controversial by the Routing RG, but the RG reached a consensus that
the document still should be published. The Routing RG has had
remarkably little consensus on anything, so virtually all Routing RG
outputs are considered controversial.
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RFC 6745 ILNPv4 ICMP November 2012
At present, the Internet research and development community is
exploring various approaches to evolving the Internet Architecture to
solve a variety of issues including, but not limited to, scalability
of inter-domain routing [RFC 4984]. A wide range of other issues
(e.g., site multihoming, node multihoming, site/subnet mobility, node
mobility) are also active concerns at present. Several different
classes of evolution are being considered by the Internet research
and development community. One class is often called "Map and
Encapsulate", where traffic would be mapped and then tunnelled
through the inter-domain core of the Internet. Another class being
considered is sometimes known as "Identifier/Locator Split". This
document relates to a proposal that is in the latter class of
evolutionary approaches.
The Identifier-Locator Network Protocol (ILNP) is a proposal for
evolving the Internet Architecture. It differs from the current
Internet Architecture primarily by deprecating the concept of an IP
Address and instead defining two new objects, each having crisp
syntax and semantics. The first new object is the Locator, a
topology-dependent name for a subnetwork. The other new object is
the Identifier, which provides a topology-independent name for a
node.
1.1. Document Roadmap
This document describes a new ICMPv4 Locator Update message used by
an ILNP node to inform its correspondent nodes of any changes to its
set of valid Locators.
The ILNP architecture can have more than one engineering
instantiation. For example, one can imagine a "clean-slate"
engineering design based on the ILNP architecture. In separate
documents, we describe two specific engineering instances of ILNP.
The term "ILNPv6" refers precisely to an instance of ILNP that is
based upon, and is backwards compatible with, IPv6. The term
"ILNPv4" refers precisely to an instance of ILNP that is based upon,
and backwards compatible with, IPv4.
Many engineering aspects common to both ILNPv4 and ILNPv6 are
described in [RFC 6741]. A full engineering specification for either
ILNPv6 or ILNPv4 is beyond the scope of this document.
Readers are referred to other related ILNP documents for details not
described here:
a) [RFC 6740] is the main architectural description of ILNP, including
the concept of operations.
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RFC 6745 ILNPv4 ICMP November 2012
b) [RFC 6741] describes engineering and implementation considerations
that are common to both ILNPv4 and ILNPv6.
c) [RFC 6742] defines additional DNS resource records that support
ILNP.
d) [RFC 6743] defines a new ICMPv6 Locator Update message used by an
ILNP node to inform its correspondent nodes of any changes to its
set of valid Locators.
e) [RFC 6744] defines a new IPv6 Nonce Destination Option used by
ILNPv6 nodes (1) to indicate to ILNP correspondent nodes (by
inclusion within the initial packets of an ILNP session) that the
node is operating in the ILNP mode and (2) to prevent off-path
attacks against ILNP ICMP messages. This Nonce is used, for
example, with all ILNP ICMPv6 Locator Update messages that are
exchanged among ILNP correspondent nodes.
f) [RFC 6746] defines a new IPv4 Nonce Option used by ILNPv4 nodes to
carry a security nonce to prevent off-path attacks against ILNP
ICMP messages, and it also defines a new IPv4 Identifier Option
used by ILNPv4 nodes.
g) [RFC 6747] describes extensions to Address Resolution Protocol
(ARP) for use with ILNPv4.
h) [RFC 6748] describes optional engineering and deployment functions
for ILNP. These are not required for the operation or use of ILNP
and are provided as additional options.
1.2. ICMPv4 Locator Update
As described in [RFC 6740] and [RFC 6741], an ILNP for IPv4 (ILNPv4)
node might need to inform correspondent ILNPv4 nodes of changes to
the set of valid Locator values. The new ICMPv4 Locator Update
message described in this document enables an ILNP-capable node to
update its correspondents about the currently valid set of Locators
valid to use in reaching the node sending this message [RFC 2460]
[RFC 4443].
This new ICMPv4 message MUST ONLY be used for ILNPv4 sessions.
Authentication is always required, as described in the Security
Considerations section later in this document.
Some might consider any and all use of ICMP to be undesirable.
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RFC 6745 ILNPv4 ICMP November 2012
In that context, please note that while this specification uses ICMP,
on grounds that this is a control message, there is no architectural
difference between using ICMP and using some different framing, for
example UDP.
1.3. 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 [RFC 2119].
2. ICMP Locator Update Message for ILNPv4
The ICMP for IPv4 message described in this section has ICMP Type 253
(as defined for experimental use in Section 8 of [RFC 4727]) and is
used ONLY with a current ILNPv4 session. This message enables an
ILNPv4 node to advertise changes to the active Locator set for the
ILNPv4 node that originates this message to its unicast ILNP
correspondent nodes. It also enables those correspondents to
acknowledge receipt of the advertisement.
This particular ICMP for IPv4 message MUST ONLY be used with ILNPv4
sessions. The Checksum field for this message is calculated
identically as for any other IPv4 ICMP message.
ICMP Locator Update message
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 | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Locs | Operation | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Locator [1] /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preference [1] | Lifetime [1] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Locator [2] /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preference [2] | Lifetime [2] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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RFC 6745 ILNPv4 ICMP November 2012
ICMP Fields:
Type 253
This type value is taken from Section 8
of [RFC 4727] and is allocated for
experimental use.
Code 0
Checksum The 16-bit one's complement of the
one's complement sum of the ICMP
message, starting with the ICMP Type.
For computing the checksum, the
Checksum field is set to 0.
Num of Locs The number of 32-bit Locator values
that are advertised in this message.
Locator[i], The 32-bit Locator values currently
i = 1..Num of Locs valid for the sending ILNPv4 node.
Preference[i], The preferability of each Locator[i],
i = 1..Num of Locs relative to other valid Locator[i]
values. The Preference numbers here
are identical, both in syntax and
semantics, to the Preference values
for L32 records that are specified by
[RFC 6742].
Lifetime[i] The maximum number of seconds that this
i = 1..Num of Locs particular Locator may be considered
valid. Normally, this is identical
to the DNS lifetime of the
corresponding L32 record, if one
exists.
Operation The value in this field indicates
whether this is a Locator Update
Advertisement (0x01) or a Locator
Update Acknowledgement (0x02).
RESERVED A field reserved for possible future
use. At present, the sender MUST
initialise this field to zero.
Receivers should ignore this field at
present. The field might be used for
some protocol function in future.
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RFC 6745 ILNPv4 ICMP November 2012
NOTE WELL: The ICMP Type value is allocated for shared
experimental use in Section 8 of [RFC 4727].
It is not uniquely assigned to ILNPv4. So,
implementations need to code particularly
defensively as other IPv4 experiments might be
using this same ICMP Type value for an
entirely different purpose with a different
ICMP packet format.
The Operation field has value 1 (hexadecimal 0x01) for a Locator
Update Advertisement. The Operation field has value 2 (hexadecimal
0x02) for a Locator Update Acknowledgement. All other values of the
Operation field are reserved for future use by future revisions of
this specification.
A node whose set of valid Locators has changed MUST send Locator
Update Advertisement messages to each correspondent node for each
active unicast ILNP session. For unicast ILNP sessions, the receiver
of a valid (i.e., authentication checks all passed, advertisement is
received from a current correspondent node) Locator Update
Advertisement addressed to the receiver MUST send a Locator Update
Acknowledgement back to the sender of the Locator Update
Advertisement. The Acknowledgement message body is identical to the
received Advertisement message body, except for the Operation value.
All ILNPv4 ICMP Locator Update messages MUST contain a valid ILNPv4
Identifier Option and MUST contain an ILNPv4 Nonce Option.
ILNPv4 ICMP Locator Update messages also MAY be protected using IP
Security for ILNP [RFC 6741] [RFC 4301]. Deployments in high-threat
environments SHOULD also protect ILNPv4 ICMP Locator Update messages
using IPsec. While IPsec Encapsulating Security Payload (ESP) can
protect a payload, no form of IPsec ESP is able to protect an IPv4
Option that appears prior to the ESP header. Note that even when IP
Security for ILNP is in use, the ILNPv4 Nonce Option still MUST be
present. This simplifies protocol processing, and it also means that
a receiver can perform the inexpensive check of the Nonce value
before performing any (potentially expensive) cryptographic
calculation.
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RFC 6745 ILNPv4 ICMP November 2012
3. Transport Protocol Effects
The ICMP Locator Update message has no impact on any transport
protocol.
The ICMP Locator Update message might affect where packets for a
given transport-layer session are sent, but an ILNP design objective
is to decouple transport protocols (e.g., TCP, UDP, SCTP) and
transport-layer sessions network-layer changes.
4. Implementation Considerations
Implementers may use any internal implementation they wish, provided
that the external appearance is the same as this implementation
approach.
To support ILNPv4, and to retain the incremental deployability and
backwards compatibility needed, the network layer needs a mode bit in
the Transport Control Block (or its equivalent) to track which IP
sessions are using the classic IPv4 mode and which IP sessions are
using ILNPv4 mode.
Further, when supporting ILNPv4, nodes will need to support a
Identifier Locator Communication Cache (ILCC) in the network layer as
described in [RFC 6741].
A node sending an ICMP Locator Update message MUST include all
currently valid Locator values in that message. A node receiving a
valid ICMP Locator Update message MUST replace the previously current
set of Locator values for that correspondent node in its own ILCC
with the newly received set of Locator values.
Every implementation needs to support a large number of Locator
values being sent or received in a single ICMP Locator Update
message, because a multihomed node or multihomed site might have a
large number of upstream links to different service providers, each
with its own Locator value.
It should be noted that as the ICMP Type uses an experimental value
from [RFC 4727], care should be taken when using with other protocols
also using experimental values.
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RFC 6745 ILNPv4 ICMP November 2012
5. Backwards Compatibility
This IPv4 ICMP message uses the same checksum calculations as any
other IPv4 ICMP message.
When ILNPv4 is not in use, the receiving IPv4 mode MUST discard the
ICMP Locator Update packet without processing the packet.
6. Security Considerations
Security considerations for the overall ILNP Architecture are
described in [RFC 6740]. Additional common security considerations
are described in [RFC 6741]. This section describes security
considerations specific to ILNPv4 topics discussed in this document.
The ICMPv4 Locator Update message MUST ONLY be used for ILNPv4
sessions.
The ILNPv4 Nonce Option [RFC 6746] MUST be present in packets
containing an ICMPv4 Locator Update message. Further, the received
Nonce Destination Option must contain the correct nonce value for the
packet to be accepted by the recipient and then passed to the ICMPv4
protocol for processing. If either of these requirements are not
met, the received packet MUST be discarded as a forgery, and a
security event SHOULD be logged by the system receiving the non-
authentic packet.
ILNP sessions operating in higher risk environments SHOULD use IP
Security for ILNP [RFC 6741] [RFC 4301] *in addition* to the ILNPv4
Nonce Option. Use of IP Security for ILNP to protect a packet does
NOT permit the packet to be sent without the Nonce Option.
Implementations need to support the case where a single ICMP Locator
Update message contains a large number of Locator and Preference
values and ought not develop a security fault (e.g., stack overflow)
due to a received message containing more Locator values than
expected.
If the ILNP Nonce value is predictable, then an off-path attacker
might be able to forge data or control packets. This risk also is
mitigated by the existing common practice of IP Source Address
filtering [RFC 2827] [RFC 3704].
Atkinson & Bhatti Experimental PAGE 9
RFC 6745 ILNPv4 ICMP November 2012
7. IANA Considerations
This document makes no request of IANA.
If in the future the IETF decided to standardise ILNPv4, then
allocation of a unique ICMP Type for the Locator Update as part of
the IETF standardisation process would be sensible.
8. References
8.1. Normative References
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC 4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", RFC 4443, March
2006.
[RFC 4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC 4727] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC
4272, January 2006.
[RFC 6740] Atkinson, R. and S. Bhatti, "Identifier-Locator Network
Protocol (ILNP) Architectural Description", RFC 6740,
November 2012.
[RFC 6747] Atkinson, R. and S. Bhatti, "Address Resolution Protocol
(ARP) Extension for the Identifier-Locator Network
Protocol for IPv4 (ILNPv4)", RFC 6747, November 2012.
[RFC 6741] Atkinson, R. and S. Bhatti, "Identifier-Locator Network
Protocol (ILNP) Engineering and Implementation
Considerations", RFC 6741, November 2012.
[RFC 6746] Atkinson, R. and S.Bhatti, "IPv4 Options for the
Identifier-Locator Network Protocol (ILNP)", RFC 6746,
November 2012.
Atkinson & Bhatti Experimental PAGE 10
RFC 6745 ILNPv4 ICMP November 2012
8.2. Informative References
[RFC 2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP
Source Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC 3704] Baker, F. and P. Savola, "Ingress Filtering for
Multihomed Networks", BCP 84, RFC 3704, March 2004.
[RFC 4984] Meyer, D., Ed., Zhang, L., Ed., and K. Fall, Ed., "Report
from the IAB Workshop on Routing and Addressing", RFC
4984, September 2007.
[RFC 6742] Atkinson, R., Bhatti, S. and S. Rose, "DNS Resource
Records for the Identifier-Locator Network Protocol
(ILNP)", RFC 6742, November 2012.
[RFC 6748] Atkinson, R. and S. Bhatti, "Optional Advanced Deployment
Scenarios for the Identifier-Locator Network Protocol
(ILNP)", RFC 6748, November 2012.
[RFC 6743] Atkinson, R. and S. Bhatti, "ICMPv6 Locator Update
Message", RFC 6743, November 2012.
[RFC 6744] Atkinson, R. and S. Bhatti, "IPv6 Nonce Destination
Option for the Identifier-Locator Network Protocol for
IPv6 (ILNPv6)", RFC 6744, November 2012.
9. Acknowledgements
Steve Blake, Stephane Bortzmeyer, Mohamed Boucadair, Noel Chiappa,
Wes George, Steve Hailes, Joel Halpern, Mark Handley, Volker Hilt,
Paul Jakma, Dae-Young Kim, Tony Li, Yakov Rehkter, Bruce Simpson,
Robin Whittle, and John Wroclawski (in alphabetical order) provided
review and feedback on earlier versions of this document. Steve
Blake provided an especially thorough review of an early version of
the entire ILNP document set, which was extremely helpful. We also
wish to thank the anonymous reviewers of the various ILNP papers for
their feedback.
Roy Arends provided expert guidance on technical and procedural
aspects of DNS issues.
Atkinson & Bhatti Experimental PAGE 11
RFC 6745 ILNPv4 ICMP November 2012
Authors' Addresses
RJ Atkinson
Consultant
San Jose, CA 95125
USA
EMail: rja.lists@gmail.com
SN Bhatti
School of Computer Science
University of St Andrews
North Haugh, St Andrews
Fife KY16 9SX
Scotland, UK
EMail: saleem@cs.st-andrews.ac.uk
Atkinson & Bhatti Experimental PAGE 12
RFC TOTAL SIZE: 25137 bytes
PUBLICATION DATE: Saturday, November 10th, 2012
LEGAL RIGHTS: The IETF Trust (see BCP 78)
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