Diameter Mobile IPv6 (MIPv6) (application id: 7 / 8)

(application id: 7 in IKEv2 scenarios, 8 in Mobile IPv6 Authentication Protocol scenarios)
The Diameter Mobile IPv6 (MIPv6) interface, as specified in RFC 5778, is a crucial component in supporting Mobile IPv6 operations within a Diameter-based Authentication, Authorization, and Accounting (AAA) infrastructure. The interface ensures that mobile nodes (MNs), which move across different networks while maintaining a consistent IP address, are properly authenticated, authorized, and accounted for.

The primary purpose of the Diameter MIPv6 interface is to facilitate the interaction between the Home Agent (HA) and the AAA server to support secure and efficient Mobile IPv6 operations. This interaction includes verifying the identity of the MN, authorizing its access to Mobile IPv6 services, and accounting for its usage of these services.
In Mobile IPv6, an MN must register with its HA to maintain its reachability as it moves across networks. The HA manages the association between the MN’s Home Address (a permanent IP address) and its Care-of Address (the IP address it acquires in the visited network). The Diameter MIPv6 interface ensures that the AAA infrastructure can verify the MN's identity and service entitlements throughout this process.

The architecture of the Diameter MIPv6 interface involves several key entities:

• Mobile Node (MN): The device that changes its point of attachment across different networks but retains a consistent Home Address.
• Home Agent (HA): The entity responsible for maintaining the binding between the MN’s Home Address and its current Care-of Address, facilitating the routing of packets to the MN’s current location.
• AAA Server: The server that provides the necessary authentication, authorization, and accounting services. It ensures that the MN is authorized to use Mobile IPv6 services and that its usage is properly accounted for.

Diameter Applications in MIPv6

• RFC 5778 defines two specific Diameter applications for MIPv6:
• MIP6I (Application ID 7): Used when the MN is authenticated and authorized using IKEv2 (Internet Key Exchange version 2).
• MIP6A (Application ID 8): Used when the MN is authenticated and authorized using the Mobile IPv6 Authentication Protocol.

These applications handle the signaling between the HA and the AAA server to ensure secure and authorized Mobile IPv6 operations.

Diameter MIPv6 interface workflow:

1. Registration Request:
   • The MN initiates a registration process with the HA. This process may involve exchanging security credentials and setting up IPsec security associations between the MN and the HA.
   • The HA, acting as a Diameter client, sends a Diameter request to the AAA server to authenticate and authorize the MN. This request includes relevant information such as the MN’s identity and any necessary credentials.
2. Authentication and Authorization:
   • The AAA server processes the request, validating the MN's credentials and verifying its authorization to use Mobile IPv6 services. The type of authentication (e.g., IKEv2 or Mobile IPv6 Authentication Protocol) dictates the specific Diameter application (MIP6I or MIP6A) used.
   • If successful, the AAA server sends a response back to the HA, confirming the MN's authentication and authorization.
3. Session Management:
   • The HA manages the session state for the MN, ensuring that the MN remains authenticated and authorized as it moves between networks. This involves maintaining the binding between the MN's Home Address and its current Care-of Address.
   • If the MN's session state changes (e.g., due to movement across networks), the HA updates the session information with the AAA server.
4. Accounting:
   • The HA reports the MN's usage of Mobile IPv6 services to the AAA server. This accounting information is critical for billing purposes and for ensuring that service providers can track and manage the MN’s resource usage.
5. Service Termination:
   • When the MN no longer requires Mobile IPv6 services, the HA terminates the session. The final accounting information is sent to the AAA server to close the session and finalize the billing records.

For complete technical specification of Diameter MIPv6 interface in Diameter protocol please refer to: [RFC5778]