draft-ietf-mip4-dynamic-assignment-05.txt   draft-ietf-mip4-dynamic-assignment-06.txt 
Mobile IP Working Group Milind Kulkarni Mobile IP Working Group Milind Kulkarni
INTERNET-DRAFT Alpesh Patel INTERNET-DRAFT Alpesh Patel
Category: Standards Track Kent Leung Category: Standards Track Kent Leung
Date : 12 August 2005 Cisco Systems Inc. Date : 12 October 2005 Cisco Systems Inc.
Mobile IPv4 Dynamic Home Agent Assignment Mobile IPv4 Dynamic Home Agent Assignment
draft-ietf-mip4-dynamic-assignment-05.txt draft-ietf-mip4-dynamic-assignment-06.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress". material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
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http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on February 13, 2006. This Internet-Draft will expire on April 12, 2006.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
Mobile IPv4 [1] uses the Home Agent (HA) to anchor sessions of a Mobile IPv4 [1] uses the Home Agent (HA) to anchor sessions of a
roaming Mobile Node (MN). This draft proposes a messaging mechanism roaming Mobile Node (MN). This draft proposes a messaging mechanism
for dynamic home agent assignment and HA redirection. The goal is to for dynamic home agent assignment and HA redirection. The goal is to
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
Mobile IPv4 [1] uses the Home Agent (HA) to anchor sessions of a Mobile IPv4 [1] uses the Home Agent (HA) to anchor sessions of a
roaming Mobile Node (MN). This draft proposes a messaging mechanism roaming Mobile Node (MN). This draft proposes a messaging mechanism
for dynamic home agent assignment and HA redirection. The goal is to for dynamic home agent assignment and HA redirection. The goal is to
provide a mechanism to assign an optimal HA for a Mobile IP session provide a mechanism to assign an optimal HA for a Mobile IP session
while allowing any suitable method for HA selection. while allowing any suitable method for HA selection.
Internet Draft Dynamic HA Assignment 12 August
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Table of Contents Table of Contents
1. Introduction................................................3 1. Introduction................................................3
2. Requirements Terminology...................................3 2. Requirements Terminology....................................3
3. Problem Statement..........................................4 3. Problem Statement...........................................4
3.1 Scope......................................................5 3.1 Scope.......................................................5
3.2 Dynamic Home Agent Discovery in Mobile IPv4................5 3.2 Dynamic Home Agent Discovery in Mobile IPv4.................5
3.3 NAI usage and dynamic HA assignment........................5 3.3 NAI usage and dynamic HA assignment.........................6
3.4 Dynamic HA Extension.......................................6 3.4 Dynamic HA Extension........................................6
3.4.1 Requested HA Extension...................................6 3.4.1 Requested HA Extension....................................6
3.4.2 Redirected HA Extension..................................7 3.4.2 Redirected HA Extension...................................7
4. Messaging mechanism for dynamic HA assignment/redirection..7 4. Messaging mechanism for dynamic HA assignment/redirection...7
4.1 Messaging for dynamic HA assignment........................7 4.1 Messaging for dynamic HA assignment.........................7
4.1.1 Example with Message Flow Diagram........................8 4.1.1 Example with Message Flow Diagram.........................8
4.2 Messaging for HA redirection..............................10 4.2 Messaging for HA redirection...............................10
4.2.1 Example with Message Flow Diagram.......................10 4.2.1 Example with Message Flow Diagram........................11
5. Mobility Agent Considerations.............................12 5. Mobility Agent Considerations..............................12
5.1 Mobile Node Considerations................................12 5.1 Mobile Node Considerations.................................12
5.1.1 MN using FA CoA.........................................13 5.1.1 MN using FA CoA..........................................13
5.1.2 MN using Co-located CoA.................................13 5.1.2 MN using Co-located CoA..................................14
5.1.3 Refreshing Assigned HA Address on Mobile Node...........14 5.1.3 Refreshing Assigned HA Address on Mobile Node............14
5.2 Foreign Agent Considerations..............................14 5.2 Foreign Agent Considerations...............................15
5.3 Home Agent Considerations.................................15 5.3 Home Agent Considerations..................................15
5.3.1 Assigned Home Agent Considerations......................15 5.3.1 Assigned Home Agent Considerations.......................16
6. Requested Home Agent Selection............................17 6. Requested Home Agent Selection.............................17
7. Error Values .............................................18 7. Error Values...............................................18
8. IANA Considerations.......................................18 8. IANA Considerations........................................18
9. Security Considerations ..................................18 9. Security Considerations....................................19
10. Backward Compatibility Considerations....................19 10. Backward Compatibility Considerations.....................20
11. Change Log from previous versions .......................20 11. Change Log from previous versions.........................21
12. Acknowledgements.........................................21 12. Acknowledgements..........................................22
13. Normative References.....................................21 13. Normative References......................................22
Authors' Addresses............................................22 Authors' Addresses.............................................22
Intellectual Property Statement...............................22 Intellectual Property Statement................................23
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1. Introduction 1. Introduction
This document adds to the Mobile IP protocol [1], by proposing a This document adds to the Mobile IP protocol [1], by proposing a
messaging mechanism for dynamic home agent assignment and home agent messaging mechanism for dynamic home agent assignment and home agent
redirection during initial registration. The goal is to assign an redirection during initial registration. The goal is to assign an
optimal HA for a Mobile IP session. The mobile node MUST use the optimal HA for a Mobile IP session. The mobile node MUST use the
Network Access Identifier (NAI) extension [2] when requesting a Network Access Identifier (NAI) extension [2] when requesting a
dynamically assigned HA. dynamically assigned HA.
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The Mobile IP related terminology described in RFC 3344 [1] is used The Mobile IP related terminology described in RFC 3344 [1] is used
in this document. In addition, the following terms are used: in this document. In addition, the following terms are used:
ALL-ZERO-ONE-ADDR: IP address 0.0.0.0 or 255.255.255.255. An ALL-ZERO-ONE-ADDR: IP address 0.0.0.0 or 255.255.255.255. An
address of 255.255.255.255 indicates a preference address of 255.255.255.255 indicates a preference
for an HA in the home domain. An address of for an HA in the home domain. An address of
0.0.0.0 indicates no preference for home vs. 0.0.0.0 indicates no preference for home vs.
visited domain. visited domain.
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Requested HA: Destination IP address of Home Agent that the Requested HA: Destination IP address of Home Agent that the
Registration Request is sent to. Must be a Registration Request is sent to. Must be a
unicast IP address. This address can be unicast IP address. This address can be
obtained as described in section 6. obtained as described in section 6.
Note that this specification defines a new Note that this specification defines a new
"Requested HA Extension" in section 3.4, which "Requested HA Extension" in section 3.4, which
is different from the term "Requested HA". is different from the term "Requested HA".
Assigned HA: The HA that accepts an MN's Registration Request Assigned HA: The HA that accepts an MN's Registration Request
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CCoA: Co-located Care of Address. CCoA: Co-located Care of Address.
MN HoA: Mobile Node's Home Address. MN HoA: Mobile Node's Home Address.
NAI: Network Access Identifier [2]. NAI: Network Access Identifier [2].
Src IP: Source IP address of the packet. Src IP: Source IP address of the packet.
Dest IP: Destination IP address of the packet. Dest IP: Destination IP address of the packet.
RRQ: Registration Request.
3. Problem Statement 3. Problem Statement
The Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept of The Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept of
identifying a MN by the NAI and enabling dynamic home address identifying a MN by the NAI and enabling dynamic home address
assignment. When the home address is dynamically assigned, it is assignment. When the home address is dynamically assigned, it is
desirable to discover the Home Agent dynamically or inform the MN desirable to discover the Home Agent dynamically or inform the MN
about an optimal HA to use for a multitude of reasons, such as: about an optimal HA to use for a multitude of reasons, such as:
Internet Draft Dynamic HA Assignment 12 August
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- If the distance between the visited network and the home network of - If the distance between the visited network and the home network of
the mobile node is large, the signaling delay for these registrations the mobile node is large, the signaling delay for these registrations
may be long. In such a case the MN will be anchored to its distant may be long. In such a case the MN will be anchored to its distant
home agent, resulting in tunneled traffic traveling a long distance home agent, resulting in tunneled traffic traveling a long distance
between home agent and the mobile node. When a Mobile IP session between home agent and the mobile node. When a Mobile IP session
initiates, if the mobile node can be assigned a home agent that is initiates, if the mobile node can be assigned a home agent that is
close to the mobile node it can drastically reduce the latency close to the mobile node it can drastically reduce the latency
between the home agent and mobile node. between the home agent and mobile node.
- In a large scale Mobile IP deployment, it is cumbersome to - In a large scale Mobile IP deployment, it is cumbersome to
provision MNs with multiple HA addresses. provision MNs with multiple HA addresses.
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home agent field of the Registration Request. This mechanism was home agent field of the Registration Request. This mechanism was
designed for mobile nodes with a static home address and subnet designed for mobile nodes with a static home address and subnet
prefix, anchored on fixed home network. However, using subnet prefix, anchored on fixed home network. However, using subnet
directed broadcast as the destination IP address of the Registration directed broadcast as the destination IP address of the Registration
Request, it is unlikely that the Registration Request will reach the Request, it is unlikely that the Registration Request will reach the
home subnet because routers will drop these packets by default. See home subnet because routers will drop these packets by default. See
CERT Advisory CA-1998-01 Smurf IP Denial-of-Service Attacks [3]. CERT Advisory CA-1998-01 Smurf IP Denial-of-Service Attacks [3].
3.3 NAI usage and dynamic HA assignment 3.3 NAI usage and dynamic HA assignment
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The Mobile IPv4 NAI Extension for IPv4 [2] introduced the The Mobile IPv4 NAI Extension for IPv4 [2] introduced the
concept of identifying a MN by the NAI and enabling dynamic concept of identifying a MN by the NAI and enabling dynamic
home address assignment. This document requires that while home address assignment. This document requires that while
using dynamic HA assignment, MN MUST use the NAI and obtain a home using dynamic HA assignment, MN MUST use the NAI and obtain a home
address. MN can still suggest a static home address in the address. MN can still suggest a static home address in the
Registration Request, but must take the address in the Registration Registration Request, but must take the address in the Registration
Reply as the home address for the session. This is compatible with Reply as the home address for the session. This is compatible with
the procedures documented in the NAI specification [2]. the procedures documented in the NAI specification [2].
3.4 Dynamic HA Extension 3.4 Dynamic HA Extension
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Length is always 4 bytes. Length is always 4 bytes.
HA-Address Address of the Home Agent. HA-Address Address of the Home Agent.
3.4.1 Requested HA Extension 3.4.1 Requested HA Extension
The Requested HA Extension is a Dynamic HA Extension of subtype 1. The Requested HA Extension is a Dynamic HA Extension of subtype 1.
The MN may include the Requested HA Extension in the registration The MN may include the Requested HA Extension in the registration
request as a hint to the network where it wishes to be anchored. request as a hint to the network where it wishes to be anchored.
This extension contains the address of the HA. A valid unicast IP This extension contains the address of the HA. A valid unicast IP
address MUST be used as HA address in this extension. address MUST be used as HA address in this extension.
Internet Draft Dynamic HA Assignment 12 August In absence of an FA, the Registration Request is forwarded to this
2005 HA. In presence of an FA, the FA MUST forward Registration Request
to the HA address in this extension.
In absence of an FA, the RRQ is forwarded to this HA. In presence of
an FA, the FA MUST forward RRQ to the HA address in this extension.
3.4.2 Redirected HA Extension 3.4.2 Redirected HA Extension
The Redirected HA Extension is a Dynamic HA Extension of subtype 2. The Redirected HA Extension is a Dynamic HA Extension of subtype 2.
The Redirected HA Extension contains the address of the HA where the The Redirected HA Extension contains the address of the HA where the
MN should attempt the next registration. The HA receiving a MN should attempt the next registration. The HA receiving a
Registration Request can suggest an alternate HA and, if so, the Registration Request can suggest an alternate HA and, if so, the
Registration Reply is sent with a new error code REDIRECT-HA-REQ and Registration Reply is sent with a new error code REDIRECT-HA-REQ and
the alternate HA address is specified in this extension. the alternate HA address is specified in this extension.
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The MN sets the Home Agent address field in the Registration The MN sets the Home Agent address field in the Registration
Request to the HA address (instead of setting it to ALL-ZERO-ONE- Request to the HA address (instead of setting it to ALL-ZERO-ONE-
ADDR). The MN also adds the same HA address in the Requested HA ADDR). The MN also adds the same HA address in the Requested HA
Extension in the Registration Request. Extension in the Registration Request.
3. The MN (if using co-located CoA and registering directly with the 3. The MN (if using co-located CoA and registering directly with the
HA) or the FA (if the MN is registering via the FA) sends the HA) or the FA (if the MN is registering via the FA) sends the
Registration Request to the "Requested HA". If the Requested HA Registration Request to the "Requested HA". If the Requested HA
Extension is present, Requested HA is specified in the "HA Extension is present, Requested HA is specified in the "HA
Address" of this extension. Address" of this extension.
Internet Draft Dynamic HA Assignment 12 August
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Per section 10, in case of a legacy FA, legacy FA forwards the Per section 10, in case of a legacy FA, legacy FA forwards the
Registration Request to the address in the HA field of the Registration Request to the address in the HA field of the
Request (thus, MN uses step 2 above in case of legacy FA instead Request (thus, MN uses step 2 above in case of legacy FA instead
of step 1). of step 1).
4. The "Requested HA" is the home agent that processes the 4. The "Requested HA" is the home agent that processes the
Registration Request in accordance with Mobile IPv4 [1] and as Registration Request in accordance with Mobile IPv4 [1] and as
per the specification in this document. It creates mobility per the specification in this document. It creates mobility
binding for successful Registration Request. It also sends a binding for successful Registration Request. It also sends a
Registration Reply to the MN. Registration Reply to the MN.
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| | | | | |
| | | | | |
| | 3 | | | 3 |
| 4 |<---------------| | 4 |<---------------|
|<------------| | |<------------| |
| | | | | |
| | 5 | | | 5 |
|----------------------------->| |----------------------------->|
| | | | | |
Internet Draft Dynamic HA Assignment 12 August
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Figure 2: Example message flow for dynamic HA assignment Figure 2: Example message flow for dynamic HA assignment
1. The MN sets the Home Agent address field in the Registration 1. The MN sets the Home Agent address field in the Registration
Request to ALL-ZERO-ONE-ADDR. Since the MN is using FA CoA in this Request to ALL-ZERO-ONE-ADDR. Since the MN is using FA CoA in this
example, it sends the Registration Request to the FA. The example, it sends the Registration Request to the FA. The
Registration Request is formatted as follows: Registration Request is formatted as follows:
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
| MN | FA | | ALL-ZERO-ONE-ADDR |FA CoA | | MN | FA | | ALL-ZERO-ONE-ADDR |FA CoA |
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| HA | the RRQ | | | | | HA | the RRQ | | | |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
4. The FA relays the Registration Reply to the MN, as follows. 4. The FA relays the Registration Reply to the MN, as follows.
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
| FA | MN | | Assigned HA |FA CoA/| | FA | MN | | Assigned HA |FA CoA/|
+-----------------------------------------------------------+ +-----------------------------------------------------------+
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5. The MN obtains the Assigned HA address from the HA field in the 5. The MN obtains the Assigned HA address from the HA field in the
successful Registration Reply and uses it for the remainder of the successful Registration Reply and uses it for the remainder of the
session. The MN sends subsequent Re-Registration or De-Registration session. The MN sends subsequent Re-Registration or De-Registration
Requests for the remainder session directly to the Assigned HA. Note Requests for the remainder session directly to the Assigned HA. The
Home Agent address field in this Registration Request is set to
that the Assigned HA is the same as the Requested HA. ALL-ZERO-ONE-ADDR. Note that the Assigned HA is the same as the
Requested HA.
4.2 Messaging for HA redirection 4.2 Messaging for HA redirection
This section describes the events that occur when the Requested HA This section describes the events that occur when the Requested HA
does not accept the Registration Request and redirects the mobile does not accept the Registration Request and redirects the mobile
node to another HA (aka Redirected HA) instead. This behavior is not node to another HA (aka Redirected HA) instead. This behavior is not
exhibited by a legacy HA and so is not referred in the description exhibited by a legacy HA and so is not referred in the description
below. In presence of a legacy FA, please refer to section 4.1 for below. In presence of a legacy FA, please refer to section 4.1 for
the specific field in the Registration Request. the specific field in the Registration Request.
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5. If the error code is set to REDIRECT-HA-REQ, MN obtains the HA 5. If the error code is set to REDIRECT-HA-REQ, MN obtains the HA
address from Redirected HA Extension. The MN then sends a address from Redirected HA Extension. The MN then sends a
Registration Request to Redirected HA, unless it has already Registration Request to Redirected HA, unless it has already
received a redirection response from this HA while processing this received a redirection response from this HA while processing this
Registration Request. The MN may choose to add Requested HA Registration Request. The MN may choose to add Requested HA
extension in this new Registration Request. extension in this new Registration Request.
4.2.1 Example with Message Flow Diagram 4.2.1 Example with Message Flow Diagram
Figure 3 shows one specific example of a Mobile Node using FA-located Figure 3 shows one specific example of a Mobile Node using FA-located
Care of Address, where the FA is not a legacy FA. Care of Address, where the FA is not a legacy FA.
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MN FA Requested HA Redirected HA MN FA Requested HA Redirected HA
| 1 | | | | 1 | | |
|------------>| 2 | | |------------>| 2 | |
| |--------------->| | | |--------------->| |
| | | | | | | |
| | | | | | | |
| | 3 | | | | 3 | |
| 4 |<---------------| | | 4 |<---------------| |
|<------------| | | |<------------| | |
| | | | | | | |
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+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
| FA |Requested HA| | ALL-ZERO-ONE-ADDR |FA CoA | | FA |Requested HA| | ALL-ZERO-ONE-ADDR |FA CoA |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
3. The HA processes the Registration Request in accordance with 3. The HA processes the Registration Request in accordance with
Mobile IPv4 [1] and the messaging defined in this specification. If Mobile IPv4 [1] and the messaging defined in this specification. If
the registration is successful, but local configuration/ the registration is successful, but local configuration/
administrative policy etc. directs HA to refer the MN to another HA, administrative policy etc. directs HA to refer the MN to another HA,
the HA rejects the Request with error code REDIRECT-HA-REQ. The HA the HA rejects the Request with error code REDIRECT-HA-REQ. The HA
fills in the address of the Redirected HA in the Redirected HA fills in the address of the Redirected HA in the Redirected HA
Internet Draft Dynamic HA Assignment 12 August
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Extension. The HA then sends Registration Reply reject to the FA, Extension. The HA then sends Registration Reply reject to the FA,
which is formatted as follows: which is formatted as follows:
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
| | Src IP of | | HA |FA CoA | | | Src IP of | | HA |FA CoA |
| HA | the RRQ | | | | | HA | the RRQ | | | |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Redirected HA Extension ... | | Redirected HA Extension ... |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
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5.1 Mobile Node Considerations 5.1 Mobile Node Considerations
The mobile node MUST use the NAI extension for home address The mobile node MUST use the NAI extension for home address
assignment when using the messaging mechanism in this document. assignment when using the messaging mechanism in this document.
Since MN uses the NAI extension, the Home Address field is set to Since MN uses the NAI extension, the Home Address field is set to
0.0.0.0. 0.0.0.0.
While dynamic HA assignment is in progress and the MN has not While dynamic HA assignment is in progress and the MN has not
successfully anchored at a Home Agent, the MN MUST set the Home Agent successfully anchored at a Home Agent, the MN MUST set the Home Agent
field in the Registration Request to an ALL-ZERO-ONE-ADDR, which is field in the Registration Request to an ALL-ZERO-ONE-ADDR, which is
either 255.255.255.255 or 0.0.0.0. either 255.255.255.255 or 0.0.0.0.
The Registration Request MUST be protected by a valid authenticator The Registration Request MUST be protected by a valid authenticator
as specified in Mobile IPv4 [1] or Mobile IPv4 Challenge/Response as specified in Mobile IPv4 [1] or Mobile IPv4 Challenge/Response
Extensions [5]. Configuring security associations is deployment Extensions [5]. Configuring security associations is deployment
specific and hence outside the scope of this specification. The specific and hence outside the scope of this specification. The
security associations between a MN and an individual HA may also be security associations between a MN and an individual HA may also be
Internet Draft Dynamic HA Assignment 12 August
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dynamically derived during the dynamic HA assignment, based on a dynamically derived during the dynamic HA assignment, based on a
shared secret between MN and AAA infrastructure [7]. shared secret between MN and AAA infrastructure [7].
The mobile node MUST maintain the remaining Mobile IP session with The mobile node MUST maintain the remaining Mobile IP session with
the Assigned HA. the Assigned HA.
As mentioned in the Security Considerations (Section 9), there is a
possibility of more than one HA create a mobility binding entry for
a given MN, if a rogue node in the middle captures the Registration
Request and forwards it to other Home Agents. MN can mitigate such
condition by using a short lifetime (e.g. 5 seconds) in the
Registration Request with Home Agent field set to ALL-ZERO-ONE-ADDR.
The following sections describe MN behavior in FA CoA mode and co- The following sections describe MN behavior in FA CoA mode and co-
located CoA mode. located CoA mode.
5.1.1 MN using FA CoA 5.1.1 MN using FA CoA
When a mobile node initiates a Mobile IP session requesting dynamic When a mobile node initiates a Mobile IP session requesting dynamic
HA assignment, it MUST set the home agent address field in the HA assignment, it MUST set the home agent address field in the
Registration Request to ALL-ZERO-ONE-ADDR. The destination IP Registration Request to ALL-ZERO-ONE-ADDR. The destination IP
address of the Registration Request is the FA. The FA will determine address of the Registration Request is the FA. The FA will determine
the Requested HA and forward the Registration Request to the the Requested HA and forward the Registration Request to the
Requested HA. Registration Request processing takes place on the Requested HA. Registration Request processing takes place on the
Requested HA as per the specification in this draft. Requested HA as per the specification in this draft.
The Registration Request MUST be appropriately authenticated for the The Registration Request MUST be appropriately authenticated for the
HA to validate the Request. HA to validate the Request.
If a successful Registration Reply is received, the MN obtains the If a successful Registration Reply is received, the MN obtains the
Assigned HA from the HA field of Reply. The Assigned HA address will Assigned HA from the HA field of Reply. The Assigned HA address will
be the same as the Requested HA Extension, if it was included in the be the same as the Requested HA Extension, if it was included in the
Registration Request by the MN. Registration Request by the MN.
If a Registration Reply is received with code REDIRECT-HA-REQ, the MN If a Registration Reply is received with code REDIRECT-HA-REQ, the MN
MUST authenticate the Reply based on HA address in HA field of Reply MUST authenticate the Reply based on HA address in HA field of Reply
and attempt Registration with the HA address specified in the and attempt Registration with the HA address specified in the
Redirected HA Extension. The MN MUST put the Redirected HA address Redirected HA Extension. The MN MUST put the Redirected HA address
as the Requested HA Extension of the new Registration Request. as the Requested HA Extension of the new Registration Request.
In some cases, for the first Registration Request the MN may want to In some cases, for the first Registration Request the MN may want to
hint to the network to be anchored at a specific HA. The MN SHOULD hint to the network to be anchored at a specific HA. The MN SHOULD
put that address in the HA address of the Requested HA Extension. put that address in the HA address of the Requested HA Extension.
5.1.2 MN using Co-located CoA 5.1.2 MN using Co-located CoA
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In some cases, for the first Registration Request the MN may want to In some cases, for the first Registration Request the MN may want to
hint to the network to be anchored at a specific HA. The MN SHOULD hint to the network to be anchored at a specific HA. The MN SHOULD
put that address in the HA address of the Requested HA Extension. put that address in the HA address of the Requested HA Extension.
5.1.2 MN using Co-located CoA 5.1.2 MN using Co-located CoA
An MN in co-located CoA mode requesting dynamic HA assignment MUST An MN in co-located CoA mode requesting dynamic HA assignment MUST
set the home agent address field in the Registration Request to ALL- set the home agent address field in the Registration Request to ALL-
ZERO-ONE-ADDR. The destination IP address of the Registration ZERO-ONE-ADDR. The destination IP address of the Registration
Request is the Requested HA. Some ideas on how to select a Requested Request is the Requested HA. Some ideas on how to select a Requested
HA are briefly covered in section 6. HA are briefly covered in section 6.
If a successful Reply is received, the MN obtains the Assigned HA If a successful Reply is received, the MN obtains the Assigned HA
address from the successful Registration Reply. The Assigned HA will address from the successful Registration Reply. The Assigned HA will
be the same as Requested HA to which the Registration Request was be the same as Requested HA to which the Registration Request was
sent. The MN MUST cache the Assigned HA address for the length of sent. The MN MUST cache the Assigned HA address for the length of
the Mobile IP session. The mobile node then MUST use this previously the Mobile IP session. The mobile node then MUST use this previously
Internet Draft Dynamic HA Assignment 12 August
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cached Assigned HA address as the home agent address in subsequent cached Assigned HA address as the home agent address in subsequent
re-registration and de-registration request(s). This will make sure re-registration and de-registration request(s). This will make sure
that for the duration of the Mobile IP session, the mobile node will that for the duration of the Mobile IP session, the mobile node will
always be anchored to the assigned home agent with which it was always be anchored to the assigned home agent with which it was
initially registered. initially registered.
If a Registration Reply is received with code REDIRECT-HA-REQ, the MN If a Registration Reply is received with code REDIRECT-HA-REQ, the MN
MUST authenticate the Reply based on HA address in HA field of Reply MUST authenticate the Reply based on HA address in HA field of Reply
and attempt Registration with the HA address specified in the and attempt Registration with the HA address specified in the
Redirected HA Extension. The MN MUST put the Redirected HA in the Redirected HA Extension. The MN MUST put the Redirected HA in the
Requested HA Extension of the new Registration Request. Requested HA Extension of the new Registration Request.
In some cases, for the first Registration Request MN may want to hint In some cases, for the first Registration Request MN may want to hint
to the network to be anchored at a specific HA and the MN SHOULD put to the network to be anchored at a specific HA and the MN SHOULD put
that address in the HA address of the Requested HA Extension. that address in the HA address of the Requested HA Extension.
While requesting dynamic HA assignment and registering directly with While requesting dynamic HA assignment and registering directly with
an HA, the Requested HA Extension MUST be included and MUST contain an HA, the Requested HA Extension MUST be included and MUST contain
the address of the HA to which the Registration Request is sent. the address of the HA to which the Registration Request is sent.
When using co-located CoA but registering via a legacy FA, the HA When using co-located CoA but registering via a legacy FA, the HA
field in Reqistration Request may be set to Requested HA. field in Reqistration Request may be set to Requested HA.
If the Registration Request contains the Requested HA Extension, the If the Registration Request contains the Requested HA Extension, the
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field in Reqistration Request may be set to Requested HA. field in Reqistration Request may be set to Requested HA.
If the Registration Request contains the Requested HA Extension, the If the Registration Request contains the Requested HA Extension, the
HA address in that extension MUST match the destination IP of the HA address in that extension MUST match the destination IP of the
Request. Request.
5.1.3 Refreshing Assigned HA Address on Mobile Node 5.1.3 Refreshing Assigned HA Address on Mobile Node
When the Mobile IP session terminates, the mobile node MAY clear the When the Mobile IP session terminates, the mobile node MAY clear the
Assigned HA address cached as the home agent address. It MAY request Assigned HA address cached as the home agent address. It MAY request
a new HA address for the new Mobile IP session by not including the a new HA address for the new Mobile IP session by not including the
Requested HA Extension. The advantage of this approach is that the Requested HA Extension. The advantage of this approach is that the
mobile node will be always anchored to an optimal home agent from mobile node will be always anchored to an optimal home agent from
where it initiated the Mobile IP session. where it initiated the Mobile IP session.
Alternately, the MN may save the Assigned HA address and use it in Alternately, the MN may save the Assigned HA address and use it in
the Requested HA Extension along with ALL-ZERO-ONE-ADDR HA address in the Requested HA Extension along with ALL-ZERO-ONE-ADDR HA address in
Registration Request for a new Mobile IP session. Registration Request for a new Mobile IP session.
5.2 Foreign Agent Considerations 5.2 Foreign Agent Considerations
When the mobile node is using a FA CoA it always registers via the When the mobile node is using a FA CoA it always registers via the
FA. When the MN is using a co-located CoA it may register through a FA. When the MN is using a co-located CoA it may register through a
FA or it may register directly with an HA, unless the R bit is set in FA or it may register directly with an HA, unless the R bit is set in
the FA's agent advertisement, in which case it always registers the FA's agent advertisement, in which case it always registers
through the FA. through the FA.
When the FA receives a Registration Request with HA address field set When the FA receives a Registration Request with HA address field set
to ALL-ZERO-ONE-ADDR that doesn't contain the Requested HA Extension, to ALL-ZERO-ONE-ADDR that doesn't contain the Requested HA Extension,
the FA obtains the Requested HA address to forward the Registration the FA obtains the Requested HA address to forward the Registration
Request using means outside the scope of this specification. Some Request using means outside the scope of this specification. Some
Internet Draft Dynamic HA Assignment 12 August
2005
ideas on how to select a Requested HA are briefly covered in section ideas on how to select a Requested HA are briefly covered in section
6. 6.
If the FA cannot obtain the Requested HA to which to forward a If the FA cannot obtain the Requested HA to which to forward a
Registration Request from MN, it MUST reject request with error code Registration Request from MN, it MUST reject request with error code
NONZERO-HA-REQD. NONZERO-HA-REQD.
If the MN has included the Requested HA Extension, the FA MUST If the MN has included the Requested HA Extension, the FA MUST
forward Registration Request to the address in this extension. If forward Registration Request to the address in this extension. If
the HA address in this extension is not a routable unicast address, the HA address in this extension is not a routable unicast address,
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Registration Request with error code 136. Registration Request with error code 136.
5.3.1 Assigned Home Agent Considerations 5.3.1 Assigned Home Agent Considerations
The HA that processes the incoming Registration Request fully in The HA that processes the incoming Registration Request fully in
accordance with Mobile IPv4 [1] and this specification becomes the accordance with Mobile IPv4 [1] and this specification becomes the
Assigned HA. The Registration Request terminates at the Assigned HA. Assigned HA. The Registration Request terminates at the Assigned HA.
The Assigned HA creates one mobility binding per MN and sends The Assigned HA creates one mobility binding per MN and sends
Registration Reply to the MN by copying its address in the home agent Registration Reply to the MN by copying its address in the home agent
field and as the source IP address of the Reply. field and as the source IP address of the Reply.
Internet Draft Dynamic HA Assignment 12 August
2005
The following table summarizes the behavior of the Assigned HA, based The following table summarizes the behavior of the Assigned HA, based
on the value of the destination IP address and Home Agent field of on the value of the destination IP address and Home Agent field of
the Registration Request. the Registration Request.
Dest IP Addr HA field Processing at Assigned HA Dest IP Addr HA field Processing at Assigned HA
------------ ------------ ---------------------------------- ------------ ------------ ----------------------------------
Unicast non-unicast Mobile IPv4 [1]: There is no change Unicast non-unicast Mobile IPv4 [1]: There is no change
in handling for this case from in handling for this case from
(Must be Mobile IPv4. It is mentioned here (Must be Mobile IPv4. It is mentioned here
equal to the for reference only. equal to the for reference only.
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Table 1: Registration Request handling at Assigned HA Table 1: Registration Request handling at Assigned HA
As per the messaging proposed here, the mobile node (or the foreign As per the messaging proposed here, the mobile node (or the foreign
agent) sends the Registration Request to the Requested HA address, agent) sends the Registration Request to the Requested HA address,
which is a unicast address. Therefore, this document does not which is a unicast address. Therefore, this document does not
specify any new behavior for the case where the HA receives a subnet specify any new behavior for the case where the HA receives a subnet
directed broadcast Registration Request as specified in section directed broadcast Registration Request as specified in section
3.8.2.1 of the Mobile IPv4 specification [1]. Although the Home 3.8.2.1 of the Mobile IPv4 specification [1]. Although the Home
Agent field in the Registration Request is not a unicast address, the Agent field in the Registration Request is not a unicast address, the
destination IP address is a unicast address. This avoids the destination IP address is a unicast address. This avoids the
problem associated with subnet-directed broadcast destination IP problem associated with subnet-directed broadcast destination IP
address that may result in multiple HAs responding. Thus, there is address that may result in multiple HAs responding. Thus, there is
no need to deny the registration as stated in Mobile IPv4 [1] section no need to deny the registration as stated in Mobile IPv4 [1] section
3.8.3.2. 3.8.3.2.
Internet Draft Dynamic HA Assignment 12 August
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When the destination IP address is a unicast address and the Home When the destination IP address is a unicast address and the Home
Agent field is ALL-ZERO-ONE-ADDR, the HA accepts/denies registration Agent field is ALL-ZERO-ONE-ADDR, the HA accepts/denies registration
and sets the HA field to its own IP address in the reply (i.e. the and sets the HA field to its own IP address in the reply (i.e. the
registration is not rejected with error code 136). registration is not rejected with error code 136).
The HA can reject the request with the error code REDIRECT-HA-REQ and The HA can reject the request with the error code REDIRECT-HA-REQ and
suggest an alternate HA. This redirection can be used for load suggest an alternate HA. This redirection can be used for load
balancing, geographical proximity based on care-of-address or other balancing, geographical proximity based on care-of-address or other
reasons. The HA puts its own address in HA field of the Registration reasons. The HA puts its own address in HA field of the Registration
Reply message and puts the address of the redirected HA in the Reply message and puts the address of the redirected HA in the
Redirected HA Extension. If the HA accepts the Request, it sets the Redirected HA Extension. If the HA accepts the Request, it sets the
HA field in the Registration Reply to its own address. HA field in the Registration Reply to its own address.
The Requested HA always performs standard validity checks on the The Requested HA always performs standard validity checks on the
Registration Request. If there is any error, the Registration Registration Request. If there is any error, the Registration
Request is rejected with error codes specified in Mobile IPv4 [1]. Request is rejected with error codes specified in Mobile IPv4 [1].
6. Requested Home Agent Selection 6. Requested Home Agent Selection
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HA. This address MUST be a unicast IP address. If the MN has HA. This address MUST be a unicast IP address. If the MN has
included a Requested HA Extension in Registration Request, the HA included a Requested HA Extension in Registration Request, the HA
address in this extension is the Requested HA. address in this extension is the Requested HA.
Some example methods by which the MN or the FA may select the Some example methods by which the MN or the FA may select the
Requested HA are briefly described below: Requested HA are briefly described below:
DHCP: DHCP:
MN performs DHCP to obtain an IP address on the visited network. The MN performs DHCP to obtain an IP address on the visited network. The
Requested HA is learned from the DHCP Mobile IP Home Agent Option 68 Requested HA is learned from the DHCP Mobile IP Home Agent Option 68
[4]. MN sends Registration Request directly to this HA and receives [4]. MN sends Registration Request directly to this HA and receives
the Assigned HA to be used for the remainder of the Mobile IP the Assigned HA to be used for the remainder of the Mobile IP
session. session.
AAA: AAA:
MN performs challenge/response [5] with the FA. The FA retrieves the MN performs challenge/response [5] with the FA. The FA retrieves the
Requested HA from the AAA server and forwards the Registration Requested HA from the AAA server and forwards the Registration
Request directly to this HA. The Assigned HA sends a Registration Request directly to this HA. The Assigned HA sends a Registration
Reply to the FA, which relays it to the MN. MN uses the Assigned HA Reply to the FA, which relays it to the MN. MN uses the Assigned HA
for the remainder of the Mobile IP session. for the remainder of the Mobile IP session.
DNS: DNS:
In this case the hostname of the HA is configured on the MN or In this case the hostname of the HA is configured on the MN or
obtained by some other means; e.g., using a service location obtained by some other means; e.g., using a service location
Internet Draft Dynamic HA Assignment 12 August
2005
protocol. MN performs DNS lookup on the HA hostname. The DNS protocol. MN performs DNS lookup on the HA hostname. The DNS
infrastructure provides a resource record with information to infrastructure provides a resource record with information to
identify the optimal HA to the MN. The MN sends a Registration identify the optimal HA to the MN. The MN sends a Registration
Request directly to the HA and receives the Assigned HA to be used Request directly to the HA and receives the Assigned HA to be used
for remainder of the Mobile IP session. for remainder of the Mobile IP session.
Static configuration: Static configuration:
The HA address is statically configured on the MN. The MN sends the The HA address is statically configured on the MN. The MN sends the
Registration Request to the configured address. The Requested HA may Registration Request to the configured address. The Requested HA may
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the section in which the error code is first mentioned in this the section in which the error code is first mentioned in this
document. document.
Error Name Value Section Description Error Name Value Section Description
--------------- ----- ------- ----------------------------- --------------- ----- ------- -----------------------------
NONZERO-HA-REQD XX 5.2 Non-zero HA address required NONZERO-HA-REQD XX 5.2 Non-zero HA address required
in Registration Request. in Registration Request.
REDIRECT-HA-REQ YY 5.3 Reregister with redirected HA. REDIRECT-HA-REQ YY 5.3 Reregister with redirected HA.
8. IANA Considerations 8. IANA Considerations
The code value NONZERO-HA-REQD is a Mobile IP response code [1] taken The code value NONZERO-HA-REQD is a Mobile IP response code [1] taken
from the range of values associated with rejection by the foreign from the range of values associated with rejection by the foreign
agent (i.e. value in the range 64-127). agent (i.e. value in the range 64-127).
The code value REDIRECT-HA-REQ is a Mobile IP response code [1] taken The code value REDIRECT-HA-REQ is a Mobile IP response code [1] taken
from the range of values associated with rejection by the home agent from the range of values associated with rejection by the home agent
(i.e. value in the range 128-192). (i.e. value in the range 128-192).
The Dynamic HA Extension is assigned from the range of values The Dynamic HA Extension is assigned from the range of values
associated with skippable extensions at the home agent (i.e. value in associated with skippable extensions at the home agent (i.e. value in
the range 128-255). the range 128-255).
IANA should record the values as defined in Section 7 and 3.4. IANA should record the values as defined in Section 7 and 3.4.
9. Security Considerations 9. Security Considerations
This specification assumes that a security configuration has been This specification assumes that a security configuration has been
preconfigured between the MN and the HA or is configured along with preconfigured between the MN and the HA or is configured along with
the initial RRQ/RRP as per [7]. the initial Registration Request/Registration Reply as per [7].
Internet Draft Dynamic HA Assignment 12 August There is a possibility of more than one HA create a mobility
2005 binding entry for a given MN, if a man in the middle captures the
Registration Request with HA field set to ALL-ZERO-ONE-ADDR and
forwards it to other HAs. This scenario assumes that the rogue node
can find out the addresses of the HAs which are able to authenticate
the Registration Request. It also assumes that the rogue node has
the capability to store, duplicate, and send packets to the other HAs
within the limited time of the replay window. Otherwise these HAs
will reject the Registration Requests anyway. In addition, this type
of attack is only possible when the Requested HA Extension is not
included in the registration message. The Mobile Node can minimize
the duration of this condition by using a short lifetime (e.g. 5
seconds) in the Registration Request.
This specification does not change the security model established in This specification does not change the security model established in
Mobile IPv4 [1]. Mobile Nodes are often connected to the network via Mobile IPv4 [1]. Mobile Nodes are often connected to the network via
wireless links, which may be more prone to passive eavesdropping or wireless links, which may be more prone to passive eavesdropping or
replay attacks. Such an attack might lead to bogus registrations or replay attacks. Such an attack might lead to bogus registrations or
redirection of traffic or denial of service. redirection of traffic or denial of service.
As per the messaging in this draft, the Assigned Home Agent will As per the messaging in this draft, the Assigned Home Agent will
process the incoming Registration Request as per Mobile IPv4 [1]. process the incoming Registration Request as per Mobile IPv4 [1].
Hence the Assigned Home Agent will have same security concerns as Hence the Assigned Home Agent will have same security concerns as
that of the Home Agent in Mobile IPv4 [1]. They are addressed in that of the Home Agent in Mobile IPv4 [1]. They are addressed in
Section 5 "Security Considerations" of Mobile IPv4 [1]. Section 5 "Security Considerations" of Mobile IPv4 [1].
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Legacy Home Agent: Legacy Home Agent:
Legacy home agents may reject the Registration Request with error Legacy home agents may reject the Registration Request with error
code 136 because the Home Agent field is not a unicast address. code 136 because the Home Agent field is not a unicast address.
However, some legacy HA implementations may coincidentally process However, some legacy HA implementations may coincidentally process
the Registration Request in accordance with this draft, when the HA the Registration Request in accordance with this draft, when the HA
field in Registration Request is set to ALL-ZERO-ONE-ADDR. field in Registration Request is set to ALL-ZERO-ONE-ADDR.
Legacy Foreign Agent: Legacy Foreign Agent:
Internet Draft Dynamic HA Assignment 12 August
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Legacy foreign agents may forward a Registration Request with home Legacy foreign agents may forward a Registration Request with home
agent field set to ALL-ZERO-ONE-ADDR by setting the destination IP agent field set to ALL-ZERO-ONE-ADDR by setting the destination IP
address to ALL-ZERO-ONE-ADDR. This will result packet being dropped address to ALL-ZERO-ONE-ADDR. This will result packet being dropped
or incidentally handled by a next hop HA, adjacent to the FA. The MN or incidentally handled by a next hop HA, adjacent to the FA. The MN
may not be aware of the dropped Registration Request and may probably may not be aware of the dropped Registration Request and may probably
retry registration, thereby increasing the delay in registration. retry registration, thereby increasing the delay in registration.
To reduce the delay in registration, the MN should take following To reduce the delay in registration, the MN should take following
steps: steps:
1. The MN should send the Registration Request as specified in this 1. The MN should send the Registration Request as specified in this
specification. In other words, the MN should set the home agent specification. In other words, the MN should set the home agent
field in the Registration Request to ALL-ZERO-ONE-ADDR and also add field in the Registration Request to ALL-ZERO-ONE-ADDR and also add
the Requested HA Extension. the Requested HA Extension.
2. If the MN does not receive a Registration Reply within some time 2. If the MN does not receive a Registration Reply within some time
and/or after sending a few Registration Requests, it can assume and/or after sending a few Registration Requests, it can assume
that the Registration Request(s) has been dropped, either by a that the Registration Request(s) has been dropped, either by a
legacy FA or an incorrect HA. In addition, if the registration is legacy FA or an incorrect HA. In addition, if the registration is
denied with error code 70 (poorly formed Request), the MN can denied with error code 70 (poorly formed Request), the MN can
assume that the legacy FA cannot process this message. In either assume that the legacy FA cannot process this message. In either
case, the MN should fall back to a recovery mechanism. The MN case, the MN should fall back to a recovery mechanism. The MN
should quickly send a new Registration Request as mentioned in should quickly send a new Registration Request as mentioned in
section 4.1 step 2. This step will ensure that a legacy FA will section 4.1 step 2. This step will ensure that a legacy FA will
forward the Registration Request to the Home Agent thereby making forward the Registration Request to the Home Agent thereby making
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assume that the legacy FA cannot process this message. In either assume that the legacy FA cannot process this message. In either
case, the MN should fall back to a recovery mechanism. The MN case, the MN should fall back to a recovery mechanism. The MN
should quickly send a new Registration Request as mentioned in should quickly send a new Registration Request as mentioned in
section 4.1 step 2. This step will ensure that a legacy FA will section 4.1 step 2. This step will ensure that a legacy FA will
forward the Registration Request to the Home Agent thereby making forward the Registration Request to the Home Agent thereby making
dynamic HA assignment possible. dynamic HA assignment possible.
Legacy Mobile Node: Legacy Mobile Node:
A MN that sends a registration request to an FA which can do dynamic A MN that sends a registration request to an FA which can do dynamic
HA assignment, but does not set the HA field to ALL-ZERO-ONE-ADDR HA assignment, but does not set the HA field to ALL-ZERO-ONE-ADDR
will continue to be registered with its statically configured HA, will continue to be registered with its statically configured HA,
exactly according to RFC 3344. exactly according to RFC 3344.
11. Change Log from previous versions 11. Change Log from previous versions
Note: This section should be removed before publication. Note: This section should be removed before publication.
Changes from revision 5 to 6:
1. Updated section 4.2.1 bullet 5.
2. Fixed nits found by idnit tool.
3. Added text in section 5.1 outlining how to avoid the
possibility of multiple bindings on HAs by requiring short
lifetime for first registration request.
4. Added text in section 9 outlining possibility of multiple
bindings on HAs.
5. Added text in section 12 Acknowledgements.
Changes from revision 4 to 5: Changes from revision 4 to 5:
1. Legacy FA Considerations text was updated based on the WG 1. Legacy FA Considerations text was updated based on the WG
discussions which addressed IESG review feedback. discussions which addressed IESG review feedback.
Changes from revision 3 to 4: Changes from revision 3 to 4:
1. Text added to clarify the cases when MN is configured with HA 1. Text added to clarify the cases when MN is configured with HA
address and not configured with HA address and requests address and not configured with HA address and requests
dynamic HA assignment. dynamic HA assignment.
Internet Draft Dynamic HA Assignment 12 August
2005
2. Clarification on legacy FA section as suggested by Thomas 2. Clarification on legacy FA section as suggested by Thomas
Narten. Narten.
3. More editorial changes suggested by the chairs. 3. More editorial changes suggested by the chairs.
Changes from revision 2 to 3: Changes from revision 2 to 3:
1. More editorial changes suggested by the chairs. 1. More editorial changes suggested by the chairs.
Changes from revision 1 to 2: Changes from revision 1 to 2:
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2. Aligned the HA address at 4-byte world boundary. 2. Aligned the HA address at 4-byte world boundary.
3. The case of handling unicast HA field is removed in section 3. The case of handling unicast HA field is removed in section
5.3.1. 5.3.1.
12. Acknowledgements 12. Acknowledgements
The authors would like to thank Pete McCann for thorough review, The authors would like to thank Pete McCann for thorough review,
suggestions on security considerations and definition of ALL-ZERO- suggestions on security considerations and definition of ALL-ZERO-
ONE-ADDR. Thanks to Kuntal Chowdhury for extensive review and ONE-ADDR. Thanks to Kuntal Chowdhury for extensive review and
comments on this draft. Also thanks to Henrik Levkowetz for detailed comments on this draft. Also thanks to Henrik Levkowetz for detailed
reviews and suggestions. Thomas Narten highlighted issues for legacy reviews and suggestions. Thomas Narten highlighted issues for legacy
FA considerations. Thanks to Ahmad Muhanna for pointing out scenario
FA considerations. of multiple bindings on HAs, documented in the Security
Considerations section.
The authors would like to thank Mike Andrews, Madhavi Chandra and The authors would like to thank Mike Andrews, Madhavi Chandra and
Yoshi Tsuda for their review and suggestions. Yoshi Tsuda for their review and suggestions.
13. Normative References 13. Normative References
[1] C. Perkins, "IP Mobility Support for IPv4", RFC 3344, August [1] C. Perkins, "IP Mobility Support for IPv4", RFC 3344, August
2002. 2002.
[2] P. Calhoun and C. Perkins, "Mobile IP Network Access Identifier [2] P. Calhoun and C. Perkins, "Mobile IP Network Access Identifier
Extension for IPv4", RFC 2794, March 2000. Extension for IPv4", RFC 2794, March 2000.
skipping to change at page 22, line 5 skipping to change at page 22, line 50
Routers", RFC 2644, August 1999. Routers", RFC 2644, August 1999.
[4] S. Alexander and R. Droms, "DHCP Options and BOOTP Vendor [4] S. Alexander and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997. Extensions", RFC 2132, March 1997.
[5] C. Perkins and P. Calhoun, "Mobile IPv4 Challenge/Response [5] C. Perkins and P. Calhoun, "Mobile IPv4 Challenge/Response
Extensions", RFC 3012, November 2000. Extensions", RFC 3012, November 2000.
[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement [6] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[7] C. Perkins and P. Calhoun, "AAA Registration Keys for Mobile [7] C. Perkins and P. Calhoun, "AAA Registration Keys for Mobile
IP", draft-ietf-mip4-aaa-key-06.txt, June 2004. IP", draft-ietf-mip4-aaa-key-06.txt, June 2004.
Internet Draft Dynamic HA Assignment 12 August
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Authors' Addresses Authors' Addresses
Milind Kulkarni Milind Kulkarni
Cisco Systems Inc. Cisco Systems Inc.
170 W. Tasman Drive, 170 W. Tasman Drive,
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: mkulkarn@cisco.com Email: mkulkarn@cisco.com
Phone:+1 408-527-8382 Phone:+1 408-527-8382
Alpesh Patel Alpesh Patel
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San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: kleung@cisco.com Email: kleung@cisco.com
Phone: +1 408-526-5030 Phone: +1 408-526-5030
Intellectual Property Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. made any independent effort to identify any such rights.
Information on the procedures with respect to rights in RFC documents Information on the procedures with respect to rights in RFC documents
can be found in BCP 78 and BCP 79. can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
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specification can be obtained from the IETF on-line IPR repository specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr. at http://www.ietf.org/ipr.
Internet Draft Dynamic HA Assignment 12 August
2005
The IETF invites any interested party to bring to its attention The IETF invites any interested party to bring to its attention
any copyrights, patents or patent applications, or other any copyrights, patents or patent applications, or other
proprietary rights that may cover technology that may be required to proprietary rights that may cover technology that may be required to
implement this standard. Please address the information to the IETF implement this standard. Please address the information to the IETF
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Disclaimer of Validity Disclaimer of Validity
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
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