Internet DRAFT - draft-perkins-mext-hatunaddr
draft-perkins-mext-hatunaddr
Mobility Extensions for IPv6 [mext] C. Perkins
Internet-Draft Tellabs Inc.
Expires: May 3, 2012 October 31, 2011
Alternate Tunnel Source Address for Home Agent
draft-perkins-mext-hatunaddr-02.txt
Abstract
Widely deployed mobility management systems for wireless
communications have isolated the path for forwarding data from the
control plane signaling for mobility management. To realize this
requirement with Mobile IP requires that the control functions of the
home agent be addressable at a different IP address than the source
IP address of the tunnel between the home agent and mobile node.
Similar considerations hold for mobility anchors implementing
Hierarchical Mobile IP or PMIP.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 3, 2012.
Copyright Notice
Copyright (c) 2011 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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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1. Introduction
Mobile IP [4] and Mobile IPv6 [5] associate the Home Agent's IP
address both with the target of control messages form the mobile
node, and the source IP address for packets tunneled to the mobile
node from the Home Agent. However, in most contemporary commercial
mobility management systems, these two IP addresses are not the same.
Thus, Mobile IP has been seen as missing an important feature, and
perhaps for that reason not fully integrated into the mobility
management systems for commercial wireless ISPs. In this document,
we specify a simple extension for Mobile IPv6 to enable a mobile node
to receive packets tunneled to it from an IP address different from
the IP address used for sending Binding Updates and other control
messages from Mobile IPv6. The extension is applied to the Binding
Acknowledgement message, which is expected to be processed by the
mobile node before any packets are tunneled to the mobile node from
the home agent. Almost identical considerations hold for Mobile
IPv4, Proxy MIP [2], Hierarchical Mobile IP [3]. Similar extensions
to the registration messages in those MIP variations will also be
specified in this document.
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2. Alternate Home Agent Tunnel Address for Mobile IPv6
The "Alternate Home Agent Tunnel Address" option may be included as
an extension to the Binding Acknowledgement message. The Alternate
Home Agent Tunnel Address option has an alignment requirement of
8n+6. Its format is as follows:
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 = TBD | Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Alternate Home Agent Tunnel Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The "Alternate Home Agent Tunnel Address" option may be included as
an extension to the Binding Acknowledgement message. When the mobile
node receives Binding Acknowledgement message including the Alternate
Home Agent Tunnel Address, it should enable decapsulation for packets
arriving from that alternate address. Moreover, the mobile node MUST
then use the alternate HA tunnel IP address whenever tunneling
packets (using IPv6-in-IPv6 encapsulation [1]) through that the home
agent.
If the Binding Acknowledgement message has the 'P' set, it is being
sent from the LMA to the MAG, and is called a "Proxy Binding
Acknowledgement" message. In this case, the "Alternate Home Agent
Tunnel Address" option may also be included. When the MAG receives
such a Proxy Binding Acknowledgement message including the Alternate
Home Agent Tunnel Address, it should enable decapsulation for packets
arriving from that alternate address. Moreover, the MAG MUST then
use the alternate HA tunnel IP address whenever tunneling the mobile
node's packets to that LMA.
If the mobile node sets the 'M' bit in the Binding Update, then the
effect is to register a regional care-of address with the local MAP
as defined in Hierarchical Mobile IP [3]. In this case, Binding
Acknowledgement message may also include the "Alternate Home Agent
Tunnel Address" option. When the mobile node receives such a Binding
Acknowledgement message including the Alternate Home Agent Tunnel
Address, it should enable decapsulation for packets arriving from
that alternate address. Moreover, the mobile node MUST then use the
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alternate HA tunnel IP address whenever tunneling the mobile node's
packets to that MAP.
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3. Alternate Home Agent Tunnel Address for Mobile IPv4
The "Alternate Home Agent Tunnel Address" option may be included as
an extension to the Registration Reply message. Its format is as
follows:
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 = TBD | Length = 6 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Alternate IPv4 Home Agent Tunnel Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reserved
Sent as zero; ignored on reception.
Alternate IPv4 Home Agent Tunnel Address
The Alternate IPv4 Home Agent Tunnel Address required by this home
agent.
The home agent may include the "Alternate IPv4 Home Agent Tunnel
Address" as an extension to the Registration Reply message. When the
mobile node receives Registration Reply message including the
Alternate IPv4 Home Agent Tunnel Address, it MUST enable
decapsulation for packets arriving from that alternate address.
Moreover, the mobile node MUST then use the alternate HA tunnel IP
address whenever tunneling packets through that the home agent.
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4. Security Considerations
This document does not introduce any security mechanisms, and does
not have any impact on existing security mechanisms. Since the
Binding Acknowledgement and Registration Reply messages to the mobile
node are required to be secured, including the Alternate Home Agent
Tunnel Address extension will not enable a malicious node to create
any disruption to the desired tunneling behavior along the data path.
In cases where confidentiality is required for traffic between the
mobile node and HA-D [i.e., the data-plane home-agent] tunnel
termination IP address, a security association will be required. For
this, there are at least two options:
IKEv2
The mobile node and HA-D can establish a security association
using IKEv2 [7]
Update to RFC 3957 (Authentication, Authorization, and Accounting
(AAA) Registration Keys for Mobile IPv4)
A new extension for the Binding Acknowledgement and/or
Registration Reply could be specified for use by the mobile node
to calculate a shared secret and establish a derived security
association with the HA-D. This extension would be similar to the
"Generalized MN Key Generation Nonce" extensions already specified
in RFC 3957 [6]
For the second option, a new calculation is needed in order to ensure
that the IP addresses of both the HA-D and the mobile node are
included in the input for the cryptographic hash function.
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5. IANA Considerations
This document creates a new Mobility Option for Mobile IPv6 that can
be included in the Binding Acknowledgement message. The protocol
number for this new Mobility Option, the "Alternate Home Agent Tunnel
Address" option, should be allocated from the space of Mobility
Options for Mobile IPv6.
This document creates a new Extension for Mobile IPv4 that can be
included in the Registration Reply message. The protocol number for
this new Extension, the "Alternate IPv4 Home Agent Tunnel Address"
option, should be allocated from the space of non-skippable
extensions for Mobile IPv4 (i.e., a number within the range 0--127).
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6. References
6.1. Normative References
[1] Conta, A. and S. Deering, "Generic Packet Tunneling in IPv6
Specification", RFC 2473, December 1998.
[2] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and
B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[3] Soliman, H., Castelluccia, C., ElMalki, K., and L. Bellier,
"Hierarchical Mobile IPv6 (HMIPv6) Mobility Management",
RFC 5380, October 2008.
[4] Perkins, C., "IP Mobility Support for IPv4, Revised", RFC 5944,
November 2010.
[5] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in
IPv6", RFC 6275, July 2011.
6.2. Informative References
[6] Perkins, C. and P. Calhoun, "Authentication, Authorization, and
Accounting (AAA) Registration Keys for Mobile IPv4", RFC 3957,
March 2005.
[7] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, "Internet Key
Exchange Protocol Version 2 (IKEv2)", RFC 5996, September 2010.
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Author's Address
Charles E. Perkins
Tellabs Inc.
3590 North, 1st Street, Suite 300
San Jose, CA 95134
USA
Email: charliep@computer.org
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