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This Internet-Draft will expire on August 15, 2008.
This document specifies protocol enhancements that allow Mobile IPv4 entities to send and receive explicit notification messages using a new Mobile IPv4 message type designed for this purpose.
1.
Introduction
2.
Terminology
3.
Notification message - Usage Scenario's
3.1.
Notification message from a Home Agent to a Mobile Node
3.1.1.
Mobile Registered using a Foreign Agent Care-of Address
3.1.2.
Mobile Registered using a Co-located Care-of Address
3.2.
Notification message from a Foreign Agent to a Mobile Node
3.3.
Notification message from a Home Agent to a Foreign Agent
4.
Generic Notification Message and Considerations
4.1.
Generic Notification Message
4.2.
Generic Notification Acknowledgment Message
4.3.
Mobile Node Consideration
4.3.1.
Receiving Generic Notification Messages
4.3.2.
Sending Generic Notification Acknowledgement Message
4.4.
Foreign Agent Consideration
4.4.1.
Receiving Generic Notification Message
4.4.2.
Sending Generic Notification Acknowledgement Messages
4.4.3.
Sending Generic Notification Messages
4.4.4.
Receiving Generic Notification Acknowledgement Messages
4.5.
Home Agent Consideration
4.5.1.
Sending Generic Notification Messages
4.5.2.
Receiving Generic Notification Acknowledgement Messages
4.5.3.
Receiving Generic Notification Messages
4.5.4.
Sending Generic Notification Acknowledgement Messages
5.
Usage Example
5.1.
Revocation Extension
5.2.
Generic String Extension
6.
Security Considerations
7.
IANA Considerations
8.
Normative References
§
Authors' Addresses
§
Intellectual Property and Copyright Statements
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In some situations, there is a need for Mobile IPv4 entities, such as the home agent, foreign agent and mobile node to send and receive asynchronous notification messages during a mobility session. The base Mobile IP Specification [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.) does not have a provision for this.
This document defines a generic message and a notification model that can be used by Mobile IPv4 entities to send various notifications. However, this specification does not define any specific notification message or the actions that the receiving entity is required to perform on receiving that message. Specific extensions and the corresponding handler actions are outside the scope of this document.
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It is assumed that the reader is familiar with the terminology used in [RFC3543] (Glass, S. and M. Chandra, “Registration Revocation in Mobile IPv4,” August 2003.), [RFC4917] (Sastry, V., Leung, K., and A. Patel, “Mobile IPv4 Message String Extension,” June 2007.), [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). In addition, the following terms are defined:
Notification Message
A message from a mobility agent to a mobile node or other mobility agent to asynchronously notify it about an event that is relevant to the mobility service it is currently providing.
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119, [RFC2119] (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.).
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There are several scenarios where a mobility agent could initiate notification events. Some of these are described in the following sections.
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In this case, the home agent cannot directly notify the mobile node, but must send the notification via the foreign agent.
+----+ notification +----+ notification +----+ | MN |<================| FA |<=============| HA | +----+ +----+ +----+
| Figure 1: Home Agent notifies Mobile Node through Foreign Agent |
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In this case, the mobile node has registered with the home agent directly, so the notification message can go directly to the mobile node.
The notification mechanism as specified here does not support the case of Co-located CoA mode with registration through a foreign agent (due to the 'R' bit being set in the foreign agent's advertisement messages).
+----+ notification +----+ | MN |<===================================| HA | +----+ +----+
| Figure 2: Home Agent directly notifies Mobile Node |
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There are two cases where a foreign agent may send notification messages to a mobile node, one where it is relaying a message, the other where the notification is triggered by a message from another network entity, for example a AAA node(notification messages between a AAA entity and the foreign agent could be based on RADIUS or Diameter, but this is out of scope for this document). If the notification is initiated by a foreign agent, the foreign agent may need to also notify the home agent about the event.
+----+ notification +----+ notification +--------+
| MN |<================| FA |<=============| AAA/HA |
+----+ +----+ +--------+
|| notification +----+
================>| HA |
+----+
| Figure 3: Foreign Agent notifies Mobile Node |
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The home agent may also need to send a notification to the foreign agent, but not to the mobile node, as illustrated below:
+----+ notification +----+ | FA |<=============| HA | +----+ +----+
| Figure 4: Home Agent notifies Foreign Agent |
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This section describes in detail the generic notification message, generic notification acknowledgement message, and some considerations related to the handling of these messages in the mobile node, foreign agent and home agent.
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A generic notification message is sent by a mobility agent to inform another mobility agent, or a mobile node, of MIP-related information. These messages must use the same IP and UDP headers as any previous Registration Request or Reply message to the same entity. The generic notification message is defined as follows:
IP Fields:
- Source Address
- Sender's address.
- Destination Address
- Receiver's address.
UDP Fields:
- Source Port
- variable.
- Destination Port
- Same as the last Registration Reply/Request message.
The UDP header is followed by the Mobile IP fields shown below:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Subtype | MD |A| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Home Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Home Agent Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Care-of Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Identification +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions...
+-+-+-+-+-+-+-+-+-+-+-+-+-
Type (TBD)
Subtype
This field describes the particular type of notification which is carried in the notification message. The following values are reserved in this document.
0 Reserved
1 Information carried in Vendor specific extensions
The value 0 is reserved and should not be used. The value 1 indicates that the actual information is carried in vendor specific extensions. Other values are reserved for future extensions.
MD: Message Direction
This memo defines the semantics of the following MD field value:
0 -- Message sent by the home agent to the mobile node
1 -- Message sent by the home agent to the foreign agent
2 -- Message sent by the mobile node to the home agent
3 -- Message sent by the mobile node to the foreign agent
4 -- Message sent by the foreign agent to the mobile node
5 -- Message sent by the foreing agent to the home agent
A
This bit indicates whether the notification message MUST be acknowledged by the recipient.
Set to "1" to indicate that acknowledgement is required.
Set to "0" to indicate that acknowledgement is optional.
Reserved
MUST be sent as 0, and ignored when received.
Home Address
The home IP address of the mobile node.
Home Agent Address
The IP address of the mobile node's home agent.
Care-of Address
The mobile node's care-of address, either the Co-located Care-of Address or the foreign agent care-of address.
Identification
A 64-bit number, constructed by the sender, used for matching Generic Notification with Generic Notification Acknowledgement, and for protecting against replay attacks of notification messages. See Sections 5.4 and 5.7 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
Extensions
The fixed portion of the Generic Notification Message is followed by one or more extensions which may be used with this message, and by one or more authentication extensions (as defined in Section 3.5 of [RFC3344]). See Sections 3.6.1.3 and 3.7.2.2 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.) for information on the relative order in which different extensions, when present, must be placed in a Generic Notification Message.
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A generic notification acknowledgement message is sent by mobility agents or mobile nodes to indicate the successful receipt of a generic notification message.
IP Fields:
- Source Address
- Typically copied from the destination address of the Generic Notification to which the agent is replying.
- Destination Address
- Copied from the source address of the Generic Notification to which the agent is replying.
UDP Fields:
- Source Port
- variable.
- Destination Port
- Copied from the source port of the corresponding Generic Notification.
The UDP header is followed by the Mobile IP fields shown below:
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | MD | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Agent Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Care-of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions... +-+-+-+-+-+-+-+-+-+-+-+-+-
Type (TBD)
Subtype
This field specifies the particular type of notification acknowledgement message. The following values are reserved in this document.
0 Reserved
1 Information carried in Vendor specific extensions
The value 0 is reserved and should not be used. The value 1 indicates that the actual information is carried in vendor specific extensions. Other values are reserved for future extensions.
MD: Message Direction
This memo defines the semantics of the following MD field value:
0 -- Message sent by the home agent to the mobile node
1 -- Message sent by the home agent to the foreign agent
2 -- Message sent by the mobile node to the home agent
3 -- Message sent by the mobile node to the foreign agent
4 -- Message sent by the foreign agent to the mobile node
5 -- Message sent by the foreing agent to the home agent
Reserved
MUST be sent as 0, and ignored when received.
Home Address
The home IP address of the mobile node.
Home Agent Address
The IP address of the sender's home agent.
Care-of Address
The mobile node's care-of address, either the Co-located Care-of Address or the foreign agent care-of address.
Identification
A 64-bit number used for matching Generic Notification with Generic Notification Acknowledgement, and for protecting against replay attacks of generic notification messages. The value is based on the Identification field from the Generic Notification message from the sender, and on the style of replay protection used in the security context between the receiver and sender (defined by the mobility security association between them, and SPI value in the authorization-enabling extension). See Sections 5.4 and 5.7 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
Extensions
The fixed portion of the generic notification acknowledgement message is followed by one or more of the Extensions listed in Section 3.5 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). See Sections 3.6.1.3 and 3.7.2.2 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.) for information on the relative order in which different extensions, when present, MUST be placed in a Generic Notification message.
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It is possible that the mobile node MAY receive a generic notification message from a foreign agent or home agent. Both in the case of FA-CoA and Co-located CoA, the mobile node MAY reply with a Generic Notification Acknowledgement message based on the "A" flag in the notification message.
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When the mobile node is using FA-CoA and receives a Notification message, if the "MD" value is 0, it means that the notification message came from the home agent. If the "MD" value is 4, the notification came from the foreign agent.
If this notification message came from a foreign agent and the mobile node accepts the foreign agent's generic notification message, it will process the notification extension according to the specific rules for that extension. After that, the mobile node MAY reply with a Generic Notification Acknowledgement message back to the foreign agent. If the "A" flag is set in the notification message, then the mobile node MUST send the acknowledgement.
If this notification message came from the home agent, relayed by the foreign agent, or is a Co-located CoA, the Mobile-Home Authentication extension MUST be checked and the mobile node MUST check the Authenticator value in the Extension. If no Mobile-Home Authentication Extension is found, or if more than one Mobile-Home Authentication Extension is found, or if the Authenticator is invalid, the mobile node MUST silently discard the Notification message. If the mobile node accepts the home agent's generic notification message, it will process it according to the specific rules for that extension. After that, the mobile node MAY reply with a Generic Notification Acknowledgement message back to the home agent based on the "A" flag in the notification message.
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Both in the case of a Co-located CoA and FA-CoA, the mobile node MAY reply with a Generic Notification Acknowledgement Message based on the "A" flag in the notification message as follows:
If the notification message was initiated from the foreign agent to the mobile node ("MD" value is set to 4), the ordering of the extension is: any non-authentication Extensions used only by the foreign agent, followed by The Mobile-Foreign Authentication extension defined in section 3.5.3 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
In the case of a FA-CoA, the source address is the mobile node's address, the destination address is the foreign agent's address.
If the notification message was initiated from the home agent to the mobile node ("MD" value is set to 0) and in the case of Co-located CoA, the ordering of the extension is: any non-authentication Extensions used only by the home agent, followed by the Mobile-Home Authentication extension defined in section 3.5.2 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.)
In the case of a FA-CoA, the source address is the mobile node's CoA address and the destination address is the home agent's address ("MD" value is set to 2), the ordering of the extension is: any non-authentication Extensions used only by the home agent, followed by the Mobile-Home Authentication Extension defined in section 3.5.2. of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.), followed by any non-authentication Extensions used only by the foreign agent, followed by The Mobile-Foreign Authentication extension defined in section 3.5.3 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
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The foreign agent cannot only relay generic notification message from the home agent and mobile node, but it can also initiate a generic notification message to the mobile node or home agent, but only when there is a binding for the mobile node.
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If the foreign agent receives a notification message, and the "MD" value is set to 0, it means that the home agent is asking the foreign agent to relay the message to the mobile node. Otherwise, it means that the target of the notification is the foreign agent.
If the "MD" value is set to 1, the Foreign-Home Authentication extension MUST be checked, and the foreign agent MUST check the Authenticator value in the Extension. If no Foreign-Home Authentication Extension is found, or if more than one Foreign-Home Authentication Extension is found, or if the Authenticator is invalid, the foreign agent MUST silently discard the Notification message. If foreign agent accepts the home agent's generic notification message, it will process it based on the specific rules for that extension. The foreign agent MAY then reply with a Generic Notification Acknowledgement message back to the home agent based on the "A" flag in the notification message.
If the "MD" value is set to 0, the Foreign-Home Authentication extension MUST be checked, and the foreign agent MUST check the Authenticator value in the Extension. If no Foreign-Home Authentication Extension is found, or if more than one Foreign-Home Authentication Extension is found, or if the Authenticator is invalid, the foreign agent MUST silently discard the Notification message. If foreign agent accepts the home agent's generic notification message, it MUST relay the Generic Notification to the mobile node's home address as specified in the Home Address field of the Generic Notification. The foreign agent MUST NOT modify any of the fields beginning with the fixed portion of the Generic Notification message through and including the Mobile-Home Authentication Extension or other authentication extension supplied by the home agent as an authorization-enabling extension for the mobile node. Furthermore, the foreign agent MUST process and remove any Extensions following the Mobile-Home Authentication Extension and MAY append any of its own non-authentication Extensions of relevance to the mobile node, if applicable, and MUST append the Mobile-Foreign Authentication Extension, if the foreign agent shares a mobility security association with the Mobile Node.
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The foreign agent may need to either relay a Generic Notification Acknowledgemnt message between the mobile node and the home agent or send one as a response to a notification messsage that was sent to it. In both cases, the Generic Notification Acknowledgement Message is defined as follows:
The source address is the foreign agent address, the destination address is home agent address.
If the foreign agent is only relaying this message to the home agent, the foreign agent it MUST NOT modify any of the fields beginning with the fixed portion of the Generic Notification Acknowledgement through and including the Mobile-Home Authentication Extension or other authentication extension supplied by the home agent as an authorization-enabling extension for the mobile node. Furthermore, the foreign agent MUST process and remove any Extensions following the Mobile-Home Authentication Extension and MAY append any of its own non-authentication Extensions of relevance to the home agent, if applicable. It MUST also append the Foreign-Home Authentication Extension, if the foreign agent shares a mobility security association with the home agent.
If the notification message is from the home agent to the foreign agent then the "MD" value is set to 1 and the ordering of the extension is: any non-authentication Extensions used only by the home agent, followed by The Foreign-Home Authentication extension defined in section 3.5.4 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
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If the foreign agent is initiating a notification to the mobile node using the generic notification message, it MAY also notify the home agent as well.
In the message to the mobile node, the source address is the foreign agent address, the destination address is the mobile node's address, the "MD" value is set to 4, and the ordering of the extension is: the notification extension, followed by any non-authentication Extensions used only by the mobile node, followed by The Mobile-Foreign Authentication extension defined in section 3.5.3 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). Computing Authentication Extension Value is the same as section 3.5.1 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.) except the payload is the notification other than registration.
In the message to the home agent, the source address is the foreign agent's address, the destination address is the home agent's address (the "MD" value is set to 5), and the ordering of the extension is: notification extension, followed by any non-authentication Extensions used only by the home agent, followed by The Foreign-Home Authentication extension defined in section 3.5.4 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). Computing Authentication Extension Value is the same as section 3.5.1 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.) except the payload is the notification other than registration.
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In the case of a FA-CoA, if the foreign agent receives this message, and the "MD" value is set to 3, it means that the notification acknowledgement message came from the mobile node, otherwise it came from the home agent.
If the "MD" value is set to 1, and the foreign agent accepted this message, the Foreign-Home Authentication extension MUST be checked, and the home agent MUST check the Authenticator value in the Extension. If no Foreign-Home Authentication Extension is found, or if more than one Foreign-Home Authentication Extension is found, or if the Authenticator is invalid, the foreign agent MUST silently discard the Notification Acknowledgement message. If the foreign agent accepted this message, the home agent MAY also process it based on the notification event.
If the "MD" value is set to 3, and the foreign agent accepted this message, the Mobile-Foreign Authentication extension MUST be checked, and the foreign agent MUST check the Authenticator value in the Extension. If no Mobile-Foreign Authentication Extension is found, or if more than one Mobile-Foreign Authentication Extension is found, or if the Authenticator is invalid, the foreign agent MUST silently discard the Notification Acknowledgement message. If the foreign agent accepted this message, the foreign agent MAY also process it based on the notification event.
In the case of a FA-CoA and if the "MD" value is set to 2, if the foreign agent received this message, the Mobile-Foreign Authentication extension MUST be checked, and the foreign agent MUST check the Authenticator value in the Extension. If no Mobile-Foreign Authentication Extension is found, or if more than one Mobile-Foreign Authentication Extension is found, or if the Authenticator is invalid, the foreign agent MUST silently discard the Notification Acknowledgement message. If foreign agent accepted the mobile node's Generic Notification Acknowledgement message, it MUST relay this message to the home agent. The foreign agent MUST NOT modify any of the fields beginning with the fixed portion of the Generic Notification Acknowledgement message through and including the Mobile-Home Authentication Extension or other authentication extension supplied by the home agent as an authorization-enabling extension for the mobile node. Furthermore, the foreign agent MUST process and remove any Extensions following the Mobile-Home Authentication Extension and MAY append any of its own non-authentication Extensions of relevance to the home agent, if applicable, and MUST append the Foreign-Home Authentication Extension, if the foreign agent shares a mobility security association with the home agent.
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The Home agent MAY initiate a generic notification message to both the mobile node and foreign agent, and it also MAY receive a generic notification acknowledgement message from both the foreign agent and mobile node. The home agent also MAY receive a generic notification message from the foreign agent, but only when there is a binding for a mobile node. If the home agent receives a notification message from a foreign agent and there is no corresponding mobile node registration, the home agent should drop the notification message.
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In the case of a FA-CoA, the home agent may either send a notification message to notify the foreign agent, or have the foreign agent relay the notification message to the mobile node if the mobile node needs to be notified.
If the message is from the home agent to the foreign agent, the source address is the home agent's address, and the destination address is the foreign agent's address
If the foreign agent is working only as a relay agent, the "MD" value is set to 0, and the ordering of the extension is: the notification extension, followed by any non-authentication extension expected to be used by mobile node, followed by Mobile-Home Authentication Extension defined in section 3.5.2. of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.), followed by any non-authentication Extensions used only by the foreign agent, followed by The Foreign-Home Authentication extension defined in section 3.5.4 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). Computing Authentication Extension Value is the same as section 3.5.1 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
If the foreign agent is the target of this notification message, then the "MD" value is set to 1, and the ordering of the extension is: the notification extension, followed by any non-authentication Extensions used only by the foreign agent, followed by The Foreign-Home Authentication extension defined in section 3.5.4 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.). Computing Authentication Extension Value is the same as section 3.5.1 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
In the case of a Co-located CoA, the home agent MAY send a notification message directly to the mobile node if it needs to be notified. The "MD" value is set to 0, and the ordering of the extension is: the notification extension, followed by any non-authentication extension expected to be used by mobile node, followed by Mobile-Home Authentication Extension defined in section 3.5.2. of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
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In the case of a FA-CoA, if the home agent receives this message, and the "MD" value is set to 2, it means that the notification acknowledgement message came from mobile node, otherwise it came from the foreign agent.
If the "MD" value is set to 5, and the home agent accepted this message, the home agent MAY also process it based on the notification event. The Foreign-Home Authentication extension MUST be checked, and the home agent MUST check the Authenticator value in the Extension. If no Foreign-Home Authentication Extension is found, or if more than one Foreign-Home Authentication Extension is found, or if the Authenticator is invalid, the home agent MUST silently discard the Notification Acknowledgement message.
If the "MD" value is set to 2, and the home agent accepted this message, the Mobile-Home Authentication extension MUST be checked, and the home agent MUST check the Authenticator value in the Extension. If no Mobile-Home Authentication Extension is found, or if more than one Mobile-Home Authentication Extension is found, or if the Authenticator is invalid, the home agent MUST silently discard the Notification Acknowledgement message. If the home agent accepted this message, the home agent MAY also process it based on the notification event.
In the case of a Co-located CoA, if the home agent received this message, the Mobile-Home Authentication extension MUST be checked, and the home agent MUST check the Authenticator value in the Extension. If no Mobile-Home Authentication Extension is found, or if more than one Mobile-Home Authentication Extension is found, or if the Authenticator is invalid, the home agent MUST silently discard the Notification Acknowledgement message.
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The home agent MAY receive a generic notification message sent from the foreign agent. When the home agent receives this message, the Foreign-Home Authentication extension MUST be checked, and the home agent MUST check the Authenticator value in the Extension. If no Foreign-Home Authentication Extension is found, or if more than one Foreign-Home Authentication Extension is found, or if the Authenticator is invalid, the home agent MUST silently discard the Notification message. If home agent accepts the foreign agent's generic notification message, it will process it based on the notification extension. Furthermore, the home agent MAY reply with a Generic Notification Acknowledgement message back to the foreign agent based on the "A" flag in the notification message.
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If the generic notification message came from the foreign agent only, the home agent MAY reply with a generic notification acknowledgement message to the foreign agent based on the "A" flag in the notification message. If the "A" flag is set in the notification message, then the home agent MUST send a Notification Acknowledgement message. The message is as follows: The source address is home agent's address, the destination address is the foreign agent's address, the "MD" value is set to 1. The ordering of the extension is: any non-authentication Extensions used only by the foreign agent, followed by The Foreign-Home Authentication extension defined in section 3.5.4 of [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.).
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There are several applications that could use this generic notification message. for example, during handover between CDMA 2000 1x EV-DO and Wireless LAN, the PPP resource of CDMA side have to be removed on the foreign agent (PDSN) to avoid over-charging subscribers. Other applications such as registration revocation, home agent switch over, NEMO prefix changes, service or billing related events, load balancing where the home agent wants to move some of the registered mobile nodes to other home agents, service termination due to end of prepaid time, and service interruption due to system maintenance.
Here we give a example of using revocation extension and describe some possible event which could use the generic string extension [RFC3344] (Perkins, C., “IP Mobility Support for IPv4,” August 2002.)based on this notification mechanism also. There is also the possibility that this notification message could carry many extensions at once. A new VSE extension could be defined to support this notification message.
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If one agent wants to notify another agent about registration revocation [RFC3543] (Glass, S. and M. Chandra, “Registration Revocation in Mobile IPv4,” August 2003.), it could easily be carried by a generic notification message and generic notification acknowledgement by specifying the exact "Subtype" in the two messages.
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In some case, the home agent or foreign agent needs to notify the mobile node about service termination due to the end of prepaid time, or service interruption due to system maintenance. This information could be defined based on a string [RFC4917] (Sastry, V., Leung, K., and A. Patel, “Mobile IPv4 Message String Extension,” June 2007.)which is recognized by the mobile node easily. An example would be "Maintenance Stopping", "Prepaid Expire". These string MUST be strictly defined so they could be easily understood by all of the network entities. "Subtype" number would need to be decided by the working group.
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This specification operates in the security constraints and requirements of [RFC3344]. It extends the operations of mobile node, home agent and foreign agent defined in [RFC3344] to notify each other about some events. The Generic Notification message defined in the specification could carry information that modifies the mobility bindings. Therefore the message MUST be integrity protected. Replay protection MUST also be guaranteed.
RFC 3344 provides replay protection only for registration requests sent by the mobile node. There is no mechanism for replay protection for messages initiated by a Foreign Agent. The 64-bit Identification field specified in this document for the Generic Notification message is used to provide replay protection for the notification messages initiated by the Foreign Agent.
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This document describes two new messages, the Generic Notification message, section 4.1 and the Generic Notification Acknowledgement message, section 4.2. These two messages should be allocated from the same address space used by the Registration Request and Registration Reply messages in [RFC3344]. The subtype of these two messages indicate what kind of information is carried and will be under assigned by IANA namespace.
| TOC |
| [RFC2119] | Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997 (TXT, HTML, XML). |
| [RFC3344] | Perkins, C., “IP Mobility Support for IPv4,” RFC 3344, August 2002 (TXT). |
| [RFC3543] | Glass, S. and M. Chandra, “Registration Revocation in Mobile IPv4,” RFC 3543, August 2003 (TXT). |
| [RFC4917] | Sastry, V., Leung, K., and A. Patel, “Mobile IPv4 Message String Extension,” RFC 4917, June 2007 (TXT). |
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| Hui Deng | |
| China Mobile | |
| 53A,Xibianmennei Ave., | |
| Xuanwu District, | |
| Beijing 100053 | |
| China | |
| Email: | denghui@chinamobile.com |
| Henrik Levkowetz | |
| Ericsson Research | |
| Torshamsgatan 23 | |
| S-164 80, Stockholm | |
| SWEDEN | |
| Email: | henrik@levkowetz.com |
| Vijay Devarapalli | |
| Azaire Networks | |
| 4800 Great America Pkwy | |
| Santa Clara, CA 95054 | |
| USA | |
| Email: | vijay.devarapalli@azairenet.com |
| Sri Gundavelli | |
| Cisco Systems | |
| 170 W.Tasman Drive | |
| San Jose, CA 95134 | |
| USA | |
| Email: | sgundave@cisco.com |
| Brian Haley | |
| Hewlett-Packard Company | |
| 110 Spitbrook Road | |
| Nashua, NH 03062 | |
| USA | |
| Email: | brian.haley@hp.com |
| TOC |
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