Pre-handoff Registration for Mobile IP Tunnel Continuity
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Solution Overview
Problem
During hand-off transitions in mobile IP-based communication systems, there are disruptions in tunneled communication due to delays in updating care-of addresses, leading to dropped or misdirected packets, causing service interruptions.
Innovation Solution
Implementing a pre-handoff registration process that includes a registration message identifying itself as pre-handoff, specifying traffic direction, and setting a valid lifetime, allowing the home agent to recognize the new foreign network's care-of address and maintain communication continuity during the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mobile node performs standard care-of address updating during hand-off, then the mobile node can establish connectivity in the new foreign network, but communication continuity is disrupted during the transition period causing packet loss
Solution Approach 1:
The patent applies preliminary action by performing pre-handoff registration at the new foreign agent before the mobile node actually moves to the new network. The foreign agent sends a registration request to the home agent in advance, obtaining a provisional care-of address before the hand-off completes. This allows the home agent to prepare routing information beforehand, eliminating the communication disruption that would normally occur during the transition period.
2Reliability
If the home agent waits for standard registration completion before accepting traffic, then routing accuracy is maintained, but service interruptions occur during the registration process
Solution Approach 1:
The home agent performs preliminary routing setup by accepting the provisional care-of address from the foreign agent before the mobile node completes its hand-off. The home agent creates a binding cache entry with this provisional address in advance, so that when the mobile node arrives at the new network, traffic can immediately be routed to the correct location without service interruption.
Solution Approach 2:
The patent introduces a provisional care-of address as an intermediary mechanism. This temporary address serves as a placeholder that allows the home agent to begin routing traffic to the new foreign network before the mobile node is fully registered. The intermediary address bridges the gap between the old and new network locations, maintaining routing accuracy while enabling continuous service.
3Ease of operation
If packets are forwarded using the old care-of address during hand-off, then routing simplicity is maintained, but packets are misdirected causing communication failures
Solution Approach 1:
The system performs preliminary updating of the care-of address in the home agent's binding cache before the hand-off completes. The foreign agent sends the new care-of address to the home agent in advance, allowing the home agent to update its routing table proactively. This eliminates the need for complex packet forwarding rules during hand-off, as packets are automatically routed to the correct new address without misdirection.
Data Source
AI summary
The present invention solves communication disruption problems during the hand-off transition period by using a pre-handoff registration of a new foreign agent on behalf of the mobile node The pre-handoff registration message should: (1) identify itself as a pre-hand off registration message, (2) indicate direction of traffic for the pre-handoff registration time period, and (3) specify a lifetime or time period when the pre-handoff registration request will continue to be considered valid The local mobility anchor will accept traffic using the pre-handoff registration care-of address depending on the directionality indicator, but the communication traffic to or from the mobile node will not be disrupted during the transition period. Because the care-of address for the mobile node on the new foreign network can be used to direct communication traffic to or from the mobile node during this transition time period, no disruption of service will be encountered.