Multicast Handoff Fast Tree Reconstruction in Mobile IP
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Solution Overview
Problem
In mobile IP communication systems, the handoff of a source node providing a multicast service results in significant time delays and packet data loss due to the reconstruction of a source-based tree, which degrades the overall performance of the system.
Innovation Solution
A method is introduced to minimize multicast service data loss by requesting fast handoff information, notifying access routers, and controlling receivers to reconstruct a new multicast tree during the handoff process, ensuring seamless service continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a source-based tree scheme is used to establish paths between transmitter and receivers, then optimal paths are maintained and time delay decreases, but when the source node hands off, the tree must be reconstructed which causes time delay and packet data loss
Solution Approach 1:
The patent applies preliminary action by having receivers proactively detect source node handoff through monitoring IP address changes, and by having the new access router proactively construct a new source-based tree before actual data transmission resumes. This提前 detection and tree construction minimizes the time delay during handoff, as the tree is already ready when data transmission needs to continue.
Solution Approach 2:
The patent implements feedback mechanisms where receivers monitor and detect source node handoff events by tracking IP address changes. When handoff is detected, this feedback information triggers the reconstruction process. Additionally, the new access router receives feedback about the handoff event and uses it to initiate tree construction, ensuring the system responds dynamically to handoff conditions.
2Reliability
If a source-based tree scheme is used to establish paths between transmitter and receivers, then optimal paths are maintained and time delay decreases, but packet data loss occurs during tree reconstruction after handoff
Solution Approach 1:
The patent applies preliminary action by having the new access router construct the source-based tree in advance before actual multicast data transmission resumes. By preparing the tree structure beforehand, the system ensures that when data arrives, the transmission path is already established, preventing packet data loss and maintaining service reliability.
Solution Approach 2:
The patent implements skipping by rapidly detecting handoff events through IP address monitoring and quickly transitioning to the new access router. The system rushes through the handoff process by immediately initiating tree construction at the new router, minimizing the window during which packet data loss could occur.
3Loss of time
If fast handoff scheme is used to minimize time delay, then time delay is reduced, but the source node is still obliged to reconstruct a source-based tree which causes inevitable multicast service data loss
Solution Approach 1:
The patent introduces an intermediary mechanism where the access router plays a mediating role in the handoff process. The router detects handoff events, manages the tree reconstruction process, and coordinates data transmission during the transition. This intermediary approach allows the system to maintain fast handoff while preventing data loss through controlled tree reconstruction at the router level rather than requiring source node involvement.
Data Source
AI summary
Disclosed is a method for providing a multicast service when an MN performs handoff from a first AR to a second AR in a mobile IP communication system including the first AR and second AR. The MN is a source node for providing the multicast service to a number of receivers and currently performs communication with the first AR. The second AR is different from the first AR. The method includes the steps of sending a request for information for fast handoff to the first AR at the MN, notifying the MN at the first AR whether the second AR can provide the multicast service in response to the fast handoff information request, notifying the first AR at the MN that the second AR must transmit subsequently-occurring multicast service data after the MN is notified whether the second AR can provide the multicast service, notifying the second AR of handoff initiation of the MN at the first AR when the MN is notified that the second AR must transmit subsequently-occurring multicast service data, notifying the first AR of handoff initiation notification acknowledgement at the second AR after the second AR is notified of the handoff initiation, and notifying the receivers at the first AR that the MN has performed handoff from the first AR to the second AR when the first AR is notified of the handoff initiation notification acknowledgement so that the receivers are controlled to rejoin a multicast tree to be provided with the multicast service.