draft-ietf-mip4-dynamic-assignment-00.txt   draft-ietf-mip4-dynamic-assignment-01.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 : 8 January 2004 Cisco Systems Inc. Date : 28 April 2004 Cisco Systems Inc.
Mobile IPv4 Dynamic Home Agent Assignment Mobile IPv4 Dynamic Home Agent Assignment
draft-ietf-mip4-dynamic-assignment-00.txt draft-ietf-mip4-dynamic-assignment-01.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026. with all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Internet-Drafts are working documents of the Internet
Engineering Task Force (IETF), its areas, and its working Engineering Task Force (IETF), its areas, and its working
groups. Note that other groups may also distribute working groups. Note that other groups may also distribute working
documents as Internet-Drafts. documents as Internet-Drafts.
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Mobile IP (RFC 3344) uses the Home Agent (HA) to anchor Mobile IP (RFC 3344) uses the Home Agent (HA) to anchor
sessions of a roaming Mobile Node (MN). This draft proposes a sessions of a roaming Mobile Node (MN). This draft proposes a
messaging mechanism for dynamic home agent assignment and HA messaging mechanism for dynamic home agent assignment and HA
redirection. The goal is to provide a mechanism to assign an redirection. The goal is to provide a mechanism to assign an
optimal HA for a Mobile IP session while allowing any suitable optimal HA for a Mobile IP session while allowing any suitable
method for HA selection. method for HA selection.
Table of Contents Table of Contents
1. Introduction......................................................2 1. Introduction.....................................................2
2. Terminology.......................................................3 2. 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 RFC 3344.........................5 3.2 Dynamic Home Agent Discovery in RFC 3344.........................5
3.3 NAI usage and dynamic HA assignment..............................5 3.3 NAI usage and dynamic HA assignment..............................5
3.4 Redirected HA address extension..................................5 3.4 Dynamic HA extension.............................................5
4. Messaging mechanism for dynamic HA assignment/redirection.........6 3.4.1 Redirected HA extension........................................6
4.1 Messaging for dynamic HA assignment..............................6 3.4.2 Requested HA extension.........................................6
4.1.1 Example with Message Flow Diagram..............................6 4. Messaging mechanism for dynamic HA assignment/redirection.........7
4.2 Messaging for HA redirection.....................................8 4.1 Messaging for dynamic HA assignment..............................7
4.2.1 Example with Message Flow Diagram..............................9 4.1.1 Example with Message Flow Diagram..............................7
4.2.2 HA Rejects Registration Request and suggests redirection.......9 4.2 Messaging for HA redirection.....................................9
5. Mobility Agent Considerations for dynamic HA assignment..........10 4.2.1 Example with Message Flow Diagram.............................10
5.1 Mobile Node Considerations......................................10 5. Mobility Agent Considerations for dynamic HA assignment..........11
5.1.1 MN using FA CoA...............................................11 5.1 Mobile Node Considerations......................................11
5.1.2 MN using Collocated CoA.......................................11 5.1.1 MN using FA CoA...............................................12
5.1.3 Refreshing Assigned HA Address on Mobile Node.................12 5.1.2 MN using Collocated CoA.......................................12
5.2 Foreign Agent Considerations....................................12 5.1.3 Refreshing Assigned HA Address on Mobile Node.................13
5.3 Home Agent Considerations.......................................12 5.2 Foreign Agent Considerations....................................13
5.3.1 Assigned Home Agent Considerations............................13 5.3 Home Agent Considerations.......................................13
6. Requested Home Agent Selection...................................15 5.3.1 Assigned Home Agent Considerations............................14
7. Error Values.....................................................16 6. Requested Home Agent Selection...................................16
8. IANA Considerations..............................................16 7. Error Values.....................................................17
8. IANA Considerations..............................................17
9. Security Considerations..........................................17 9. Security Considerations..........................................17
9.1 Message Authentication Codes....................................17 9.1 Message Authentication Codes....................................17
9.2 Areas of Security Concern in this Protocol......................17 9.2 Areas of Security Concern in this Protocol......................18
10. Backward Compatibility Considerations...........................18 10. Backward Compatibility Considerations...........................18
11. Change Log......................................................18 11. Change Log from previous version................................19
12. Intellectual Property Rights....................................18 12. Intellectual Property Rights....................................19
13. Acknowledgements................................................19 13. Acknowledgements................................................19
14. References......................................................19 14. References......................................................19
Authors' Addresses..................................................20 Authors' Addresses..................................................20
Full Copyright Statement............................................20 Full Copyright Statement............................................20
Intellectual Property...............................................21
Acknowledgement.....................................................21
1. Introduction 1. Introduction
This document adds to the Mobile IP protocol [1], by proposing This document adds to the Mobile IP protocol [1], by proposing
a messaging mechanism for dynamic home agent assignment and a messaging mechanism for dynamic home agent assignment and
home agent redirection during initial registration. The goal is home agent redirection during initial registration. The goal is
to assign an optimal HA for a Mobile IP session. The mobile to assign an optimal HA for a Mobile IP session. The mobile
node MUST use Network Access Identifier (NAI) extension for node MUST use Network Access Identifier (NAI) extension for
home address assignment. home address assignment.
MN requests the network to dynamically assign an HA by setting MN requests the network to dynamically assign an HA by setting
HA field to ALL-ZERO-ONE-ADDR (defined in next section) in HA field to ALL-ZERO-ONE-ADDR (defined in next section) in
initial Registration Request. If the request is accepted, the initial Registration Request. If the request is accepted, the
HA field in successful Registration Reply contains the HA HA field in successful Registration Reply contains the HA
address. The requested HA can suggest an alternate HA and if address. The requested HA can suggest an alternate HA and if
so, the Registration Reply is rejected with a new error code so, the Registration Reply is rejected with a new error code
(REDIRECT-HA-REQ) and the alternate HA address is specified in (REDIRECT-HA-REQ) and the alternate HA address is specified in
a new extension (REDIRECTED-HA-ADDRESS). a new extension (Redirected HA extension).
Alternately, MN can set the HA field to a unicast address. The If the RRQ is rejected with Redirected HA extension or if the
HA receiving the Registration Request can suggest an alternate MN wishes to register at a specific HA, MN can put the HA
HA and if so, the Registration Reply is rejected with a new address in the Requested HA extension in Registration Request.
error code (REDIRECT-HA-REQ) and the alternate HA address is The HA address in Requested HA extension is a hint to the
specified in a new extension (REDIRECTED-HA-ADDRESS). The HA network where the MN may be anchored. The HA field is set to
can reject the request if the HA in request does not match any ALL-ZERO-ONE-ADDRESS for dynamic HA assignment.
of its own addresses.
The messaging mechanism proposed here is generic and can be The messaging mechanism proposed here is generic and can be
used as a common foundation to facilitate dynamic HA assignment used as a common foundation to facilitate dynamic HA assignment
using any suitable method. No specific method is either using any suitable method. No specific method is either
mandated or suggested. The HA receiving Registration Request mandated or suggested. The HA receiving Registration Request
may suggest an alternate HA (HA redirection) for a number of may suggest an alternate HA (HA redirection) for a number of
reasons; including but not limited to HA load-balancing, reasons; including but not limited to HA load-balancing,
geographical proximity, administrative policy etc. geographical proximity, administrative policy etc.
2. Terminology 2. Terminology
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be a unicast IP address. This address can be be a unicast IP address. This address can be
obtained as described in section 5.4. obtained as described in section 5.4.
Assigned HA: If registration is successful, this Home Assigned HA: If registration is successful, this Home
Agent address field is obtained from Agent address field is obtained from
successful Registration Reply. successful Registration Reply.
Redirected HA: If the registration is rejected with error Redirected HA: If the registration is rejected with error
code (REDIRECT-HA-REQ), the HA being referred code (REDIRECT-HA-REQ), the HA being referred
to is specified in a new extension to is specified in a new extension
(REDIRECTED-HA-ADDRESS). (Redirected HA extension).
AAA server: Authentication, Authorization and Accounting AAA server: Authentication, Authorization and Accounting
Server. Server.
DNS: Domain Name Service. DNS: Domain Name Service.
DHCP: Dynamic Host Configuration Protocol. DHCP: Dynamic Host Configuration Protocol.
MN: Mobile Node as defined in RFC 3344. MN: Mobile Node as defined in RFC 3344.
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3. Problem Statement 3. Problem Statement
Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept
of identifying a MN by the NAI and enabling dynamic home of identifying a MN by the NAI and enabling dynamic home
address assignment. When the home address is dynamically address assignment. When the home address is dynamically
assigned, it is desirable to discover the Home Agent assigned, it is desirable to discover the Home Agent
dynamically or inform the MN about an optimal HA to use for a dynamically or inform the MN about an optimal HA to use for a
multitude of reasons, such as: multitude of reasons, such as:
If the distance between the visited network and the home - If the distance between the visited network and the home
network of the mobile node is large, the signaling delay for network of the mobile node is large, the signaling delay for
these registrations may be long. In such a case the MN will be these registrations may be long. In such a case the MN will be
anchored to its distant home agent, resulting in tunneled anchored to its distant home agent, resulting in tunneled
traffic traveling a long distance between home agent and the traffic traveling a long distance between home agent and the
mobile node. When a Mobile IP session initiates, if the mobile mobile node. When a Mobile IP session initiates, if the mobile
node can be assigned an home agent which is close to the mobile node can be assigned a home agent, which is close to the mobile
node it can drastically reduce the latency between the home node, it can drastically reduce the latency between the home
agent and mobile node. agent and mobile node.
Also, in a large scale Mobile IP deployment, it is cumbersome - Also, in a large scale Mobile IP deployment, it is cumbersome
to provision MNs with multiple HA addresses. to provision MNs with multiple HA addresses.
It is desirable to achieve some form of load balancing between - It is desirable to achieve some form of load balancing
multiple HAs in the network. Dynamic HA assignment and/or HA between multiple HAs in the network. Dynamic HA assignment
redirection lets the network select the optimal HA from among a and/or HA redirection lets the network select the optimal HA
set of HAs and thus achieve load balancing among a group of from among a set of HAs and thus achieve load balancing among a
HAs. group of HAs.
Local administrative policies is yet another reason for dynamic - Local administrative policies is yet another reason for
HA assignment/HA redirection during the start of a Mobile IP dynamic HA assignment/HA redirection during the start of a
session. Mobile IP session.
The problem of discovering a Mobile nodeÆs HA address is - The problem of discovering a Mobile node’s HA address is
acknowledged in the MIPv6 working group as part of [8]. acknowledged in the MIPv6 working group as part of [8].
3.1 Scope 3.1 Scope
This specification assumes that the Mobile Node and Assigned This specification assumes that the Mobile Node and Assigned
Home Agent are in the same administrative domain. The scenario Home Agent are in the same administrative domain. The scenario
where the Mobile Node and its anchoring Assigned Home Agent are where the Mobile Node and its anchoring Assigned Home Agent are
in different administrative domain is beyond the scope of this in different administrative domain is beyond the scope of this
specification. specification.
The draft introduces the terms Requested/Assigned/Redirected HA The draft introduces the terms Requested/Assigned/Redirected HA
(section 5.4). These terms are merely HA addresses and used for (section 5.4). These terms are merely HA addresses and used
depending upon the direction of the registration request or depending upon the direction of the registration request or
reply. The discovery of Requested/Assigned/Redirected HA can be reply. The discovery of Requested/Assigned/Redirected HA can be
done by various means, which are network and/or deployment done by various means, which are network and/or deployment
specific and hence this discovery/assignment of specific and hence this discovery/assignment of
Requested/Assigned/Redirected HA is kept outside the scope of Requested/Assigned/Redirected HA is kept outside the scope of
this specification. this specification.
3.2 Dynamic Home Agent Discovery in RFC 3344 3.2 Dynamic Home Agent Discovery in RFC 3344
Mobile IP RFC 3344 specifies the mechanism for discovering the Mobile IP RFC 3344 specifies the mechanism for discovering the
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Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept Mobile IPv4 NAI Extension for IPv4 [2] introduced the concept
of identifying a MN by the NAI and enabling dynamic home of identifying a MN by the NAI and enabling dynamic home
address assignment. This document mandates that while using address assignment. This document mandates that while using
dynamic HA assignment, MN MUST use NAI and obtain a home dynamic HA assignment, MN MUST use NAI and obtain a home
address. MN can still suggest a static home address in address. MN can still suggest a static home address in
Registration Request, but must take the address in Registration Registration Request, but must take the address in Registration
Reply as the home address for the session. This reference to Reply as the home address for the session. This reference to
obtaining home address using NAI is as per [2]. obtaining home address using NAI is as per [2].
3.4 Redirected HA address extension 3.4 Dynamic HA extension
The Dynamic HA extension, shown in figure 1, contains the
The Redirected HA address extension, shown in figure 1, address of the HA. This is a generic extension and can be used
contains the address of the HA where the MN should attempt the in Registration Request and Reply messages. It is a skippable
next registration. It is a skippable extension and MUST be extension.
included in Registration Reply when the reply code is REDIRECT-
HA-REQ.
0 1 2 3 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 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Redirected-HA-Address | Type | Sub-Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HA-Address...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The Redirected HA address Extension Figure 1: The Dynamic HA address Extension
Type REDIRECTED-HA-ADDRESS (skippable) [1] Type DYNAMIC-HA-ADDRESS (skippable) [1] (to be
assigned by IANA) is the type, which specifies the
dynamic HA address.
Length 4 Sub-Type is a unique number given to each member in the
aggregated type.
HA-Address The address of redirected HA Length Indicates the length of the extension not including
the type, sub-type and length fields.
HA-Address The address of HA
3.4.1 Redirected HA extension
The format of the Redirected HA extension is as defined in
section 3.4. This extension uses the subtype value of 1. This
extension has the length field set to 4.
The Redirected HA extension, contains the address of the HA
where the MN should attempt the next registration. The HA
receiving a Registration Request can suggest an alternate HA
and if so, the Registration Reply is rejected with a new error
code (REDIRECT-HA-REQ) and the alternate HA address is
specified in this extension.
It MUST be included in Registration Reply when the reply code
is REDIRECT-HA-REQ.
3.4.2 Requested HA extension
The format of the Requested HA address extension is as defined
in section 3.4. This extension uses the subtype value of 2.
This extension has the length field set to 4.
MN may include the Requested HA extension in the registration
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 address MUST be used as HA address in this
extension.
In absence of an FA, the RRQ is forwarded to this HA. In
presence of an FA, FA MUST forward RRQ to the HA address in
this extension.
4. Messaging mechanism for dynamic HA assignment/redirection 4. Messaging mechanism for dynamic HA assignment/redirection
4.1 Messaging for dynamic HA assignment 4.1 Messaging for dynamic HA assignment
1. MN sets the Home Agent address field in the Registration 1. MN sets the Home Agent address field in the Registration
Request to ALL-ZERO-ONE-ADDR. Request to ALL-ZERO-ONE-ADDR.
If the MN is aware of an HA address, it can add that
address in the Requested HA extension in Registration
Request.
2. The MN (if using collocated CoA) or FA (if using FA CoA) 2. The MN (if using collocated CoA) or FA (if using FA CoA)
sends the Registration Request to the "Requested HA". sends the Registration Request to the "Requested HA".
If the Requested HA extension is present, Requested HA is
the HA address in this extension.
3. "Requested HA" is the home agent, which processes the 3. "Requested HA" is the home agent, which processes the
Registration Request in accordance with RFC 3344 and as Registration Request in accordance with RFC 3344 and as
per the specification in this document. It creates per the specification in this document. It creates
mobility binding for successful Registration Request. It mobility binding for successful Registration Request. It
also sends Registration Reply to the MN. also sends Registration Reply to the MN.
4. The MN obtains an "Assigned HA" address from the HA field 4. The MN obtains an "Assigned HA" address from the HA field
in the successful Registration Reply and uses it for the in the successful Registration Reply and uses it for the
remainder of the session. remainder of the session.
5. Subsequent Registration Request messages for renewal are 5. Subsequent Registration Request messages for renewal are
sent to the Assigned HA. sent to the Assigned HA.
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1. MN sets the Home Agent address field in the Registration 1. MN sets the Home Agent address field in the Registration
Request to ALL-ZERO-ONE-ADDR. Since MN is using FA CoA in this Request to ALL-ZERO-ONE-ADDR. Since 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 looks as follows: Registration Request looks 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 |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
If the MN is aware of an HA address, it can add that address in
the Requested HA extension in Registration Request. That
extension is not shown above.
2. The FA sends the Registration Request to the Requested HA. 2. The FA sends the Registration Request to the Requested HA.
The Registration Request looks: The Registration Request looks as follows:
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| 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 |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
If MN had included the Requested HA extension, the Registration
Request is sent to the HA address in that extension.
3. HA processes the Registration Request in accordance with RFC 3. HA processes the Registration Request in accordance with RFC
3344 and the messaging defined in this document and creates 3344 and the messaging defined in this document. HA creates
mobility binding for successful request. HA then sends mobility binding for successful request. HA then sends
Registration Reply to the FA, which looks as follows. The Registration Reply to the FA, which looks as follows. The
Assigned HA address corresponds to the HA receiving and Assigned HA address corresponds to the HA receiving and
processing the request (and is same as Requested HA, only the processing the request (and is same as Requested HA, only the
name is changed for registration reply). name is changed for registration reply).
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
|Assigned|CoA or NATed| | Assigned HA |FA CoA/| |Assigned|CoA or NATed| | Assigned HA |FA CoA/|
| HA | Src IP | | | | | HA | Src IP | | | |
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5. The MN obtains Assigned HA address from the HA field in the 5. The MN obtains Assigned HA address from the HA field in the
successful Registration Reply and uses it for the remainder of successful Registration Reply and uses it for the remainder of
the session. MN sends subsequent Re-Registration or De- the session. MN sends subsequent Re-Registration or De-
Registration Requests for the remaining session directly to the Registration Requests for the remaining session directly to the
Assigned HA. Assigned HA.
4.2 Messaging for HA redirection 4.2 Messaging for HA redirection
1. MN sets the Home Agent address field in the Registration 1. MN sets the Home Agent address field in the Registration
Request to ALL-ZERO-ONE-ADDR or unicast address. Request to ALL-ZERO-ONE-ADDR.
2. The MN (if using collocated CoA) or FA (if using FA CoA) 2. The MN (if using collocated CoA) or FA (if using FA CoA)
sends the Registration Request to the "Requested HA". sends the Registration Request to the "Requested HA". If
3. When HA receives the Registration Request, if the unicast the MN is aware of an HA address, it can add that address
HA address in Request does not match any of its addresses, in the Requested HA extension in Registration Request.
HA can reject the request with Reply code REDIRECT-HA-REQ
and suggest an alternate HA.
If the HA field is set to ALL-ZERO-ONE-ADDR, HA may reject 3. When HA receives the Registration Request, if the HA field
the request with Reply code REDIRECT-HA-REQ and suggest an is set to ALL-ZERO-ONE-ADDR, HA may reject the request
alternate HA. with Reply code REDIRECT-HA-REQ and suggest an alternate
HA.
HA may reject the Request for a number of reasons, which HA may reject the Request for a number of reasons, which
are outside the scope of this specification. If the HA are outside the scope of this specification. If the HA
rejects the Request, the HA field in the Reply is set to rejects the Request, the HA field in the Reply is set to
this HAs address. The HA that is being referred to is this HAs address. The HA that is being referred to is
specified in REDIRECTED-HA-ADDRESS extension. The presence specified in Redirected HA extension. The presence of this
of this extension is mandatory when the reply code is set extension is mandatory when the reply code is set to
to REDIRECT-HA-REQ. HA sends the Reply to the FA/MN REDIRECT-HA-REQ. HA sends the Reply to the FA/MN
4. FA sends the Reply to the MN. 4. FA sends the Reply to the MN.
5. If the error code is set to REDIRECT-HA-REQ, MN obtains 5. If the error code is set to REDIRECT-HA-REQ, MN obtains
the HA address from REDIRECTED-HA-ADDRESS and sends a the HA address from Redirected HA extension and sends a
Registration Request to this HA. Registration Request to this HA.
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 Figure 3 shows one specific example of a Mobile Node using FA
Care of Address. Care of Address.
MN FA Requested HA Redirected HA MN FA Requested HA Redirected HA
| 1 | | | | 1 | | |
|------------>| 2 | | |------------>| 2 | |
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| | 3 | | | | 3 | |
| 4 |<---------------| | | 4 |<---------------| |
|<------------| | | |<------------| | |
| | | | | | | |
| | 5 | | | | 5 | |
|-------------------------------------------------> | |-------------------------------------------------> |
| | | | | | | |
Figure 3: Example of Message flows for the specification Figure 3: Example of Message flows for the specification
4.2.2 HA Rejects Registration Request and suggests redirection
1. MN sets the Home Agent address field in the Registration 1. MN sets the Home Agent address field in the Registration
Request to ALL-ZERO-ONE-ADDR or unicast HA address. Since MN is Request to ALL-ZERO-ONE-ADDR address. Since MN is using FA CoA
using FA CoA in this example, it sends the Registration Request in this example, it sends the Registration Request to the FA.
to the FA. The Registration Request looks as follows: The Registration Request looks 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 |
| | | | or unicast addr | |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
If the MN is aware of an HA address, it can add that address in
the Requested HA extension in Registration Request. That
extension is not shown above.
2. The FA sends the Registration Request to the Requested HA. 2. The FA sends the Registration Request to the Requested HA.
Note that the Requested HA could be different from the unicast If Requested HA extension is present, Requested HA is the HA
HA address in the Request. The Registration Request looks: address in this extension. The Registration Request looks as
follows:
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| 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 |
| | | | or unicast addr | |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
3. HA processes the Registration Request in accordance with RFC 3. HA processes the Registration Request in accordance with RFC
3344 and the messaging defined in this document. If the 3344 and the messaging defined in this document. If the
registration is successful, but local configuration/ registration is successful, but local configuration/
administrative policy etc. directs HA to refer the MN to administrative policy etc. directs HA to refer the MN to
another HA, HA rejects the Request with error code REDIRECT-HA- another HA, HA rejects the Request with error code REDIRECT-HA-
REQ. HA fills in the address of the directed HA in the REQ. HA fills in the address of the directed HA in the
REDIRECTED-HA-ADDRESS extension. HA then sends Registration Redirected HA extension. HA then sends Registration Reply
Reply reject to the FA, which looks as follows: reject to the FA, which looks as follows:
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| Src IP=| Dest IP = | MN HoA | HA Address = | CoA = | | Src IP=| Dest IP = | MN HoA | HA Address = | CoA = |
| |CoA or NATed| | HA |FA CoA | | |CoA or NATed| | HA |FA CoA |
| HA | Src IP | | | | | HA | Src IP | | | |
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| REDIRECTED-HA-ADDRESS extension | | Redirected HA extension ...
+-----------------------------------------------------------+ +-----------------------------------------------------------+
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 | | HA |FA CoA/| | FA | MN | | HA |FA CoA/|
+-----------------------------------------------------------+ +-----------------------------------------------------------+
| REDIRECTED-HA-ADDRESS extension | | Redirected HA extension ...
+-----------------------------------------------------------+ +-----------------------------------------------------------+
5. If MN can authenticate the Reply, MN extracts the HA address 5. If MN can authenticate the Reply, MN extracts the HA address
from REDIRECTED-HA-ADDRESS extension and sends Registration from Redirected HA extension and sends Registration Request to
Request to this HA. this HA.
5. Mobility Agent Considerations for dynamic HA assignment 5. Mobility Agent Considerations for dynamic HA assignment
Following sections describe the behavior of each mobility agent Following sections describe the behavior of each mobility agent
in detail. in detail.
5.1 Mobile Node Considerations 5.1 Mobile Node Considerations
The mobile node MUST use NAI extension for home address The mobile node MUST use NAI extension for home address
assignment when using the messaging mechanism in this document. assignment when using the messaging mechanism in this document.
A mobile node MUST set the Home Agent field in the Registration While dynamic HA assignment is in progress and MN has not
Request to a unicast address or an ALL-ZERO-ONE-ADDR, which is successfully anchored at a Home Agent, mobile node MUST set the
either 255.255.255.255 or 0.0.0.0. Home Agent field in the Registration Request to an ALL-ZERO-
ONE-ADDR, which is either 255.255.255.255 or 0.0.0.0.
The Registration Request MUST be protected by a valid The Registration Request MUST be protected by a valid
authenticator as specified in [1] or [5]. Configuring security authenticator as specified in [1] or [5]. Configuring security
associations is deployment specific and hence outside the scope associations is deployment specific and hence outside the scope
of this specification. The security associations between a MN of this specification. The security associations between a MN
and an individual HA may also be dynamically derived during the and an individual HA may also be dynamically derived during the
dynamic HA assignment, based on a shared secret between MN and dynamic HA assignment, based on a shared secret between MN and
AAA infrastructure. AAA infrastructure.
The mobile node must maintain the remaining Mobile IP session The mobile node must maintain the remaining Mobile IP session
with the Assigned HA. Following sections describe MN behavior with the Assigned HA. Following sections describe MN behavior
in FA CoA mode and collocated CoA mode. in FA CoA mode and collocated CoA mode.
5.1.1 MN using FA CoA 5.1.1 MN using FA CoA
When a mobile node initiates Mobile IP session, it MUST set the When a mobile node initiates Mobile IP session requesting
home agent address field in the Registration Request to unicast dynamic HA assignment, it MUST set the home agent address field
address or ALL-ZERO-ONE-ADDR. The destination IP address of in the Registration Request to ALL-ZERO-ONE-ADDR. The
Registration Request is the FA. The FA will determine the destination IP address of Registration Request is the FA. The
Requested HA and forward the Registration Request to the FA will determine the Requested HA and forward the Registration
Requested HA. Registration Request processing takes place on Request to the Requested HA. Registration Request processing
the Requested HA as per the specification in this draft. takes place on the Requested HA as per the specification in
this draft.
The Registration Request MUST be appropriately authenticated The Registration Request MUST be appropriately authenticated
for the HA to validate the Request. for the HA to validate the Request.
If successful Registration Reply is received, MN obtains If successful Registration Reply is received, MN obtains
Assigned HA from the HA field of Reply. Assigned HA from the HA field of Reply.
If Registration Reply is received with code REDIRECT-HA-REQ, MN If Registration Reply is received with code REDIRECT-HA-REQ, MN
MUST authenticate the Reply based on HA address in HA field of MUST authenticate the Reply based on HA address in HA field of
Reply and attempt Registration with the HA address specified in Reply and attempt Registration with the HA address specified in
the REDIRECTED-HA-ADDRESS extension. the Redirected HA extension. In some cases, MN may want to hint
to the network to be anchored at a specific HA. In both these
cases, MN MUST put the HA address in the Requested HA extension
in Registration Request.
5.1.2 MN using Collocated CoA 5.1.2 MN using Collocated CoA
Mobile Node in collocated CoA mode MUST set the home agent Mobile Node in collocated CoA mode requesting dynamic HA
address field in the Registration Request to unicast address or assignment MUST set the home agent address field in the
ALL-ZERO-ONE-ADDR. The destination IP address of the Registration Request to ALL-ZERO-ONE-ADDR. The destination IP
Registration Request is the Requested HA. Some ideas to select address of the Registration Request is the Requested HA. Some
a Requested HA are briefly covered in section 6. ideas to select a Requested HA are briefly covered in section
6.
If successful Reply is received, the MN obtains Assigned HA If successful Reply is received, the MN obtains Assigned HA
address from successful Registration Reply. The MN MUST cache address from successful Registration Reply. The MN MUST cache
the Assigned HA address for the length of the Mobile IP the Assigned HA address for the length of the Mobile IP
session. The mobile node then MUST use this previously cached session. The mobile node then MUST use this previously cached
Assigned HA address as the home agent address in subsequent re- Assigned HA address as the home agent address in subsequent re-
registration and de-registration request(s). This will make registration and de-registration request(s). This will make
sure that the mobile node will always be anchored to the sure that the mobile node will always be anchored to the
assigned home agent with which it was initially registered. assigned home agent with which it was initially registered.
If Registration Reply is received with code REDIRECT-HA-REQ, MN If Registration Reply is received with code REDIRECT-HA-REQ, MN
MUST authenticate the Reply based on HA address in HA field of MUST authenticate the Reply based on HA address in HA field of
Reply and attempt Registration with the HA address specified in Reply and attempt Registration with the HA address specified in
the REDIRECTED-HA-ADDRESS extension. the Redirected HA extension. In some cases, MN may want to hint
to the network to be anchored at a specific HA. In both these
cases, MN MUST put the HA address in the Requested HA extension
in Registration Request.
While requesting dynamic HA assignment in collocated CoA mode,
Requested HA extension must always be included.
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 When the Mobile IP session terminates, the mobile node MAY
clear the Assigned HA address cached as the home agent address. clear the Assigned HA address cached as the home agent address.
It MAY request a new HA address for the new Mobile IP session. It MAY request a new HA address for the new Mobile IP session
The advantage of this approach is that the mobile node will be by not including the Requested HA extension. The advantage of
always anchored to an optimal home agent from where it this approach is that the mobile node will be always anchored
initiated Mobile IP session. to an optimal home agent from where it initiated Mobile IP
session.
Alternately, MN may save the Assigned HA address and use it in
the Requested HA extension along with ALL-ZERO-ONE HA address
in Registration Request.
5.2 Foreign Agent Considerations 5.2 Foreign Agent Considerations
When the mobile node is using foreign agent CoA, it sends the When the mobile node is using foreign agent CoA, it sends the
Registration Request to the foreign agent. When the FA receives Registration Request to the foreign agent. When the FA receives
a Registration Request with HA address field set to ALL-ZERO- a Registration Request with HA address field set to ALL-ZERO-
ONE-ADDR, it obtains the Requested HA address to forward the ONE-ADDR, it obtains the Requested HA address to forward the
Registration Request. Some ideas to select a Requested HA are Registration Request. Some ideas to select a Requested HA are
briefly covered in section 6. briefly covered in section 6.
If the FA cannot obtain the Requested HA to forward a If the FA cannot obtain the Requested HA to forward a
Registration Request from MN, it MUST reject request with error Registration Request from MN, it MUST reject request with error
code NONZERO-HA-REQD. code NONZERO-HA-REQD.
If the MN has included the Requested HA extension, FA MUST
forward Registration Request to the address in this extension.
If the HA address in this extension is not a routable unicast
address, FA MUST reject request with error code NONZERO-HA-
REQD.
Backward compatibility issues related to the mobility agents Backward compatibility issues related to the mobility agents
are addressed in section 9. are addressed in section 9.
5.3 Home Agent Considerations 5.3 Home Agent Considerations
Home Agent can process an incoming Registration Request in one Home Agent can process an incoming Registration Request in one
of the following three ways: of the following three ways:
MN or FA sends the Registration Request to the Requested HA. MN or FA sends the Registration Request to the Requested HA.
The term Requested HA has meaning in context of the The term Requested HA has meaning in context of the
Registration Request message. When the Requested HA Registration Request message. When the Requested HA
successfully processes Registration Request and creates a successfully processes Registration Request and creates a
binding and sends a Reply with its address, it becomes the binding and sends a Reply with its address, it becomes the
Assigned HA. The term Assigned HA is meaningful in context of a Assigned HA. The term Assigned HA is meaningful in context of a
Registration Reply message. Registration Reply message.
skipping to change at page 12, line 46 skipping to change at page 14, line 18
The term Requested HA has meaning in context of the The term Requested HA has meaning in context of the
Registration Request message. When the Requested HA Registration Request message. When the Requested HA
successfully processes Registration Request and creates a successfully processes Registration Request and creates a
binding and sends a Reply with its address, it becomes the binding and sends a Reply with its address, it becomes the
Assigned HA. The term Assigned HA is meaningful in context of a Assigned HA. The term Assigned HA is meaningful in context of a
Registration Reply message. Registration Reply message.
Home Agent receiving the request with HA field set to ALL-ZERO- Home Agent receiving the request with HA field set to ALL-ZERO-
ONE-ADDR MAY reject the request even if successfully ONE-ADDR MAY reject the request even if successfully
authenticated for a multitude of reasons and suggest an authenticated for a multitude of reasons and suggest an
alternate HA address in Reply. In such a case, the HA puts own alternate HA address in Reply. In such a case, the HA puts its
address in HA field of Reply and sets the Reply code to own address in HA field of Reply and sets the Reply code to
REDIRECT-HA-REQ and adds the REDIRECTED-HA-ADDRESS extension. REDIRECT-HA-REQ and adds the Redirected HA extension.
Home Agent receiving the request with HA field set to a unicast If the Registration Request contains the Requested HA
address not matching any of its addresses MUST reject the extension, the HA address in that extension must match the
request even if successfully authenticated. This rejected destination IP of the Request.
message has the code 136 as defined in RFC3344 (3.8.3.2). HA
may reject the message with code REDIRECT-HA-REQ and suggest
an alternate HA to use in the REDIRECTED-HA-ADDRESS extension.
5.3.1 Assigned Home Agent Considerations 5.3.1 Assigned Home Agent Considerations
The HA that processes the incoming Registration Request fully The HA that processes the incoming Registration Request fully
in accordance with RFC 3344 and this specification becomes the in accordance with RFC 3344 and this specification becomes the
Assigned HA. The Registration Request terminates at the Assigned HA. The Registration Request terminates at the
Assigned HA. Assigned HA.
The Assigned HA creates mobility bindings and sends The Assigned HA creates mobility bindings and sends
Registration Reply to the MN by copying its address in the home Registration Reply to the MN by copying its address in the home
skipping to change at page 13, line 30 skipping to change at page 14, line 49
destination IP address is unicast, only one HA receives the destination IP address is unicast, only one HA receives the
Registration Request. This HA should unambiguously accept or Registration Request. This HA should unambiguously accept or
deny the registration, regardless of the value in the Home deny the registration, regardless of the value in the Home
Agent field. When the Home Agent field is non-unicast, the HA Agent field. When the Home Agent field is non-unicast, the HA
should set the value to its own IP address in the Registration should set the value to its own IP address in the Registration
Reply. Reply.
The following table summarizes the behavior of Assigned HA. The following table summarizes the behavior of Assigned HA.
No. Dest IP Addr HA field Processing at Assigned HA No. Dest IP Addr HA field Processing at Assigned HA
-- ------------ ------------ ------------------------- -- ------------ ------------ -------------------------------
1 Unicast Unicast û RFC 3344: Normal HA processing 1 Unicast non-unicast RFC 3344: HA denies the
Same as Dest per RFC 3344.
IP addr
Unicast û RFC 3344: HA denies the
Different registration with error code
than Dest IP 136 and sets HA field to its
Addr own IP address in the reply as
per section 3.8.3.2.
OR
New Behavior: Dest IP
corresponds to the HA receiving
RRQ, if authentication is
successful, reject RRQ with a
new error code (REDIRECT-HA-
REQ). HA puts its address in HA
address field of Reject. HA
suggests an alternate HA to use
in the new REDIRECTED-HA-
ADDRESS extension.
2 Unicast non-unicast RFC 3344: HA denies the
registration with error code registration with error code
136 and sets HA field to its 136 and sets HA field to its
own IP address in the reply as own IP address in the reply as
per section 3.8.3.2. per section 3.8.3.2.
ALL-ZERO- New Behavior: Accept the RRQ as ALL-ZERO- New Behavior: Accept the RRQ as
ONE-ADDR per this specification. ONE-ADDR per this specification.
Authenticate the RRQ and create Authenticate the RRQ and create
mobility binding if the HA is mobility binding if the HA is
acting as Assigned HA. Set HA acting as Assigned HA. Set HA
skipping to change at page 14, line 29 skipping to change at page 15, line 24
OR OR
New Behavior: Dest IP New Behavior: Dest IP
corresponds to the HA receiving corresponds to the HA receiving
RRQ, if authentication is RRQ, if authentication is
successful, reject RRQ with a successful, reject RRQ with a
new error code (REDIRECT-HA- new error code (REDIRECT-HA-
REQ). HA puts its address in HA REQ). HA puts its address in HA
address field of Reject. HA address field of Reject. HA
suggests an alternate HA to use suggests an alternate HA to use
in the new REDIRECTED-HA- in the new Redirected HA
ADDRESS extension extension
3 Non-unicast Unicast RFC 3344: HA rejects with error
code 136 and sets HA field to
its own IP address in the reply
per section 3.8.2.1.
4 Non-unicast Non-unicast RFC 3344: HA rejects with error
code 136 and sets HA field to
its own IP address in the reply
per section 3.8.2.1.
Table 1: Registration Request handling at Assigned HA Table 1: Registration Request handling at Assigned HA
This specification proposes an enhancement to case #1 from RFC
3344. As per this specification, when a HA receives a
Registration Request and the HA address (unicast) does not
match its own address(es), HA can reject the request with the
error code REDIRECT-HA-REQ and suggest an alternate HA. This
redirection can be used for load-balancing, geographical
proximity based on care-of-address or a multitude of reasons.
HA puts its own address in HA field on Registration Reply
message and put the address of the redirected HA in the
REDIRECTED-HA-ADDRESS extension.
This specification also proposes a subtle difference in This specification also proposes a subtle difference in
behavior for case #2 above from RFC 3344. As per the messaging behavior for case #1 above from RFC 3344. As per the messaging
proposed here, the mobile node (or the foreign agent) sends the proposed here, the mobile node (or the foreign agent) sends the
Registration Request to the Requested HA address, which is a Registration Request to the Requested HA address, which is a
unicast address. Because HA does not receive Registration unicast address. Because HA does not receive Registration
Request that is sent to the subnet-directed broadcast address, Request that is sent to the subnet-directed broadcast address,
RFC 3344 section 3.8.2.1 doesn't apply. Although the Home RFC 3344 section 3.8.2.1 doesn't apply. Although the Home
Agent field in the Registration Request is not a unicast Agent field in the Registration Request is not a unicast
address, the destination IP address is a unicast address. This address, the destination IP address is a unicast address. This
avoids the problem associated with subnet-directed broadcast avoids the problem associated with subnet-directed broadcast
destination IP address that may result in multiple HAs destination IP address that may result in multiple HAs
responding. Thus, there is no need to deny the registration as responding. Thus, there is no need to deny the registration as
skipping to change at page 15, line 30 skipping to change at page 16, line 4
When the destination IP address is a unicast address and Home When the destination IP address is a unicast address and Home
Agent field is ALL-ZERO-ONE-ADDR, the HA accepts/denies Agent field is ALL-ZERO-ONE-ADDR, the HA accepts/denies
registration and sets HA field to its own IP address in the registration and sets HA field to its own IP address in the
reply (i.e. registration is not rejected with error code 136). reply (i.e. registration is not rejected with error code 136).
HA can reject the request with the error code REDIRECT-HA-REQ HA can reject the request with the error code REDIRECT-HA-REQ
and suggest an alternate HA. This redirection can be used for and suggest an alternate HA. This redirection can be used for
load-balancing, geographical proximity based on care-of-address load-balancing, geographical proximity based on care-of-address
or a multitude of reasons. HA puts its own address in HA field or a multitude of reasons. HA puts its own address in HA field
on Registration Reply message and put the address of the on Registration Reply message and put the address of the
redirected HA in the REDIRECTED-HA-ADDRESS extension. If HA redirected HA in the Redirected HA extension. If HA accepts the
accepts the Request, HA field in Reply is set to this HA Request, HA field in Reply is set to this HA address.
address.
The Assigned HA performs standard validity checks on the The Assigned HA 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 RFC 3344. Request is rejected with error codes specified in RFC 3344.
6. Requested Home Agent Selection 6. Requested Home Agent Selection
The destination IP address of the first Registration Request in The destination IP address of the Registration Request when
the Mobile IP session is the Requested HA. This address MUST dynamic HA assignment is requested, is the Requested HA. This
be a unicast IP address. address MUST be a unicast IP address. If the MN has included a
Requested HA extension in Registration Request, the HA address
in this extension is the Requested HA.
Some ideas on how to select the Requested HA are briefly Some ideas on how to select the Requested HA are briefly
covered in this section, however this draft neither suggests covered in this section, however this draft neither suggests
nor mandates any specific mechanism. There can be more methods nor mandates any specific mechanism. There can be more methods
for selecting the HA to the MN. Here is a high level overview for selecting the HA to the MN. Here is a high level overview
of some possibilities: of some possibilities:
DHCP: DHCP:
MN performs DHCP to obtain an IP address on the visited MN performs DHCP to obtain an IP address on the visited
skipping to change at page 16, line 20 skipping to change at page 16, line 45
MN performs challenge/response [5] with the FA. The FA MN performs challenge/response [5] with the FA. The FA
retrieves the Requested HA from the AAA server and forwards the retrieves the Requested HA from the AAA server and forwards the
Registration Request directly to this HA. The Assigned HA Registration Request directly to this HA. The Assigned HA
sends Registration Reply to the FA, which relays it to the MN. sends Registration Reply to the FA, which relays it to the MN.
MN uses the Assigned HA for the remainder of the Mobile IP MN uses the Assigned HA for the remainder of the Mobile IP
session. session.
DNS: DNS:
In this case hostname of HA is configured on MN or obtained by In this case hostname of HA is configured on MN or obtained by
some other means û e.g. using a service location protocol. MN some other means e.g. using a service location protocol. MN
performs DNS lookup on the HA hostname. The DNS infrastructure performs DNS lookup on the HA hostname. The DNS infrastructure
provides resource record with information to identify the provides resource record with information to identify the
nearest HA to the MN. The MN sends Registration Request nearest HA to the MN. The MN sends Registration Request
directly to the HA and receives the Assigned HA to be used for directly to the HA and receives the Assigned HA to be used for
remainder of the Mobile IP session. remainder of the Mobile IP session.
Static configuration: Static configuration:
HA address is statically configured on MN. The MN uses the HA address is statically configured on MN. The MN uses the
configured address to send the Registration Request. configured address to send the Registration Request.
skipping to change at page 16, line 43 skipping to change at page 17, line 21
Each entry in the following table contains the name and value Each entry in the following table contains the name and value
for the error code to be returned in a Registration Reply. It for the error code to be returned in a Registration Reply. It
also includes the section in which the error code is first also includes the section in which the error code is first
mentioned in this document. mentioned in this 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 5.3.1 Reregister with suggested HA. REDIRECT-HA-REQ YY 5.3.1 Reregister with redirected HA.
8. IANA Considerations 8. IANA Considerations
The code value NONZERO-HA-REQD defined in Section 7 correspond The code value NONZERO-HA-REQD defined in Section 7, correspond
to error values conventionally associated with the rejection by to error values conventionally associated with the rejection by
the foreign agent (i.e. value in the range 64-127). The code the foreign agent (i.e. value in the range 64-127). The code
value REDIRECT-HA-REQ defined in Section 7 correspond to error value REDIRECT-HA-REQ defined in Section 7, correspond to error
values conventionally associated with the rejection by the home values conventionally associated with the rejection by the home
agent (i.e. value in the range 128-192). agent (i.e. value in the range 128-192).
The extension REDIRECTED-HA-ADDRESS defined in section 3.3 The Dynamic HA extension defined in section 3.4 corresponds to
corresponds to a skippable extension. a skippable extension.
IANA should record the values as defined in Section 7 and 3.3. IANA should record the values as defined in Section 7 and 3.4.
9. Security Considerations 9. Security Considerations
This specification assumes that the Mobile Node and Assigned This specification assumes that the Mobile Node and Assigned
Home Agent are in the same administrative domain. This Home Agent are in the same administrative domain. This
specification does not change or degrade the security model specification does not change or degrade the security model
established in RFC-3344. Most of the time Mobile Nodes will be established in RFC-3344. Most of the time Mobile Nodes will be
connected to the network via wireless link. Such links are connected to the network via wireless link. Such links are
vulnerable to passive eavesdropping, replay attacks or many vulnerable to passive eavesdropping, replay attacks or many
other types of attacks. They are considered below. other types of attacks. They are considered below.
9.1 Message Authentication Codes 9.1 Message Authentication Codes
The Registration Request and Reply messages are protected by a The Registration Request and Registration Reply messages are
valid authenticator as specified in RFC 3344. Configuring protected by a valid authenticator as specified in RFC 3344.
security associations is a deployment specific issue and is Configuring security associations is a deployment specific
covered by other specifications in Mobile IP WG. There can be issue and is covered by other specifications in Mobile IP WG.
many ways of configuring security associations, but this
specification does not mandate any specific way. There can be many ways of configuring security associations,
but this specification does not mandate any specific way.
An example is where the security association between a MN and An example is where the security association between a MN and
an individual HA (Dynamic or Assigned) is dynamically derived an individual HA (Dynamic or Assigned) is dynamically derived
during the dynamic HA assignment, based on a shared secret during the dynamic HA assignment, based on a shared secret
between MN and AAA infrastructure, as defined in [7]. The between MN and AAA infrastructure, as defined in [7]. The
Registration Request is protected with MN-AAA authentication Registration Request is protected with MN-AAA authentication
extension and Registration Reply is protected with MHAE. Since extension and Registration Reply is protected with MHAE. Since
the security association is shared between MN and AAA, any the security association is shared between MN and AAA, any
dynamically assigned HA in the local domain can proxy dynamically assigned HA in the local domain can proxy
authenticate the MN using AAA as per [7]. authenticate the MN using AAA as per [7].
skipping to change at page 17, line 52 skipping to change at page 18, line 29
the mobile node as specified in RFC-3344 and RFC-3012. The MN the mobile node as specified in RFC-3344 and RFC-3012. The MN
also authenticates the Registration Reply from the Assigned HA, also authenticates the Registration Reply from the Assigned HA,
thus the existing trust model in RFC 3344 is maintained. thus the existing trust model in RFC 3344 is maintained.
9.2 Areas of Security Concern in this Protocol 9.2 Areas of Security Concern in this Protocol
As per the messaging in this draft, the Assigned Home Agent As per the messaging in this draft, the Assigned Home Agent
will process the incoming Registration Request as per RFC-3344. will process the incoming Registration Request as per RFC-3344.
Hence the Assigned Home Agent will have same security concerns Hence the Assigned Home Agent will have same security concerns
as that of the Home Agent in RFC-3344. They are addressed in as that of the Home Agent in RFC-3344. They are addressed in
Section 5 ôSecurity Considerationsö of RFC-3344. Section 5 “Security Considerations” of RFC-3344.
10. Backward Compatibility Considerations 10. Backward Compatibility Considerations
Legacy Home Agent: Legacy Home Agent:
Legacy home agents may reject the Registration Request with Legacy home agents may reject the Registration Request with
error code 136 because the Home Agent field is not a unicast error code 136 because the Home Agent field is not a unicast
address. However, some legacy HA implementations may address. However, some legacy HA implementations may
coincidentally process the Registration Request in accordance coincidentally process the Registration Request in accordance
with this draft, when the HA field in RRQ is set to ALL-ZERO- with this draft, when the HA field in RRQ is set to ALL-ZERO-
skipping to change at page 18, line 31 skipping to change at page 19, line 7
packet being dropped or incidentally handled by a next hop HA, packet being dropped or incidentally handled by a next hop HA,
adjacent to the FA. adjacent to the FA.
Legacy Mobile Node: Legacy Mobile Node:
MN that does not set HA field to ALL-ZERO-ONE-ADDR will MN that does not set HA field to ALL-ZERO-ONE-ADDR will
continue to achieve its registrations through statically continue to achieve its registrations through statically
configured HA. In collocated mode, the endpoint of the MN's configured HA. In collocated mode, the endpoint of the MN's
tunnel is the Assigned HA. tunnel is the Assigned HA.
11. Change Log 11. Change Log from previous version
Version 2 is totally revamped from earlier version. The most
notable changes are:
Removed references to directed HA/assigned HA. There is no HA
redirection in the network to incorporate the feedback from
Pete McCann. The single entity is currently called Assigned HA.
Added a new error code for HA rejection when dst IP is unicast
and HA address is unicast and these two addresses are
different. The HA receiving RRQ rejects the RRQ and puts
another HA in RRP and its source address in RRP.
Also, when this new error code is used for HA redirection, a 1. Added subtype field in Redirected HA Address Extension.
new HA address is suggested in a new extension 2. Aligned the HA address at 4-byte world boundary.
3. The case of handling unicast HA field is removed in section
5.3.1.
12. Intellectual Property Rights 12. Intellectual Property Rights
The IETF takes no position regarding the validity or scope of The IETF takes no position regarding the validity or scope of
any intellectual property or other rights that might be claimed any intellectual property or other rights that might be claimed
to pertain to the implementation or use of the technology to pertain to the implementation or use of the technology
described in this document or the extent to which any license described in this document or the extent to which any license
under such rights might or might not be available; neither does under such rights might or might not be available; neither does
it represent that it has made any effort to identify any such it represent that it has made any effort to identify any such
rights. Information on the IETF's procedures with respect to rights. Information on the IETF's procedures with respect to
skipping to change at page 19, line 47 skipping to change at page 20, line 15
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.
[3] D. Senie, "Changing the Default for Directed Broadcasts in [3] D. Senie, "Changing the Default for Directed Broadcasts in
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] H. Levkowetz and S. Vaarala, "Mobile IP Traversal of Network [6] H. Levkowetz and S. Vaarala, "Mobile IP Traversal of Network
Address Translation (NAT) Devices", RFC 3519, July 803. Address Translation (NAT) Devices", RFC 3519, April 2003.
[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-mobileip-aaa-key-13.txt, 22 June 2003. IP", draft-ietf-mobileip-aaa-key-13.txt, 22 June 2003.
[8] Jari Arkko, et. al., ôThoughts on bootstrapping mobility [8] Jari Arkko, et. al., “Thoughts on bootstrapping mobility
securelyö as presented at 57th IETF in Vienna, Austria, 16th securely” as presented at 57th IETF in Vienna, Austria, 16th
July, 2003 July, 2003
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
skipping to change at page 20, line 34 skipping to change at page 21, line 4
Kent Leung Kent Leung
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: kleung@cisco.com Email: kleung@cisco.com
Phone: +1 408-526-5030 Phone: +1 408-526-5030
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is
subject to the rights, licenses and restrictions contained in
BCP 78 and except as set forth therein, the authors retain all
their rights.
Copyright (C) The Internet Society (2002). All Rights This document and the information contained herein are provided
Reserved. on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION
HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET
SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
This document and translations of it may be copied and Intellectual Property
furnished to others, and derivative works that comment on or
otherwise explain it or assist in its implementation may be
prepared, copied, published and distributed, in whole or in
part, without restriction of any kind, provided that the above
copyright notice and this paragraph are included on all such
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not be modified in any way, such as by removing the copyright
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organizations, except as needed for the purpose of developing
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defined in the Internet Standards process must be followed, or
as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will The IETF takes no position regarding the validity or scope of
not be revoked by the Internet Society or its successors or any Intellectual Property Rights or other rights that might be
assigns. claimed to pertain to the implementation or use of the
technology described in this document or the extent to which
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