FMIPv6 Handoff TCP Packet Interception via Previous Access Router
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In FMIPv6 environments, handoff delays lead to communication cutoff events during TCP-based communications for mobile nodes, as they roam, resulting in reduced packet transmission rates due to TCP protocol characteristics, particularly during handoff periods where mobile nodes are not physically connected to a wireless access point.
Innovation Solution
A handoff method in FMIPv6 where the previous access router intercepts TCP packets from the correspondent node, generates and sends TCP ACKs to the correspondent node through a bi-directional tunnel, ensuring seamless TCP packet transmission by maintaining packet flow and preventing communication cutoffs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Fast Mobile IPv6 (FMIPv6) is used to reduce handoff delays, then handoff speed is improved, but TCP communication cutoff events occur during handoff due to mobile nodes being physically disconnected from access points
Solution Approach 1:
The patent introduces the previous access router as an intermediary that intercepts TCP packets destined for the mobile node and forwards them through a bi-directional tunnel to the new access router. This mediator ensures TCP communication continuity by preventing packet loss during the handoff transition period when the mobile node is physically disconnected.
Solution Approach 2:
The patent establishes a bi-directional tunnel between the previous access router and the new access router before the mobile node completes its handoff. This preliminary action ensures that the packet forwarding path is ready in advance, allowing seamless TCP communication without interruption when the mobile node switches access points.
2Reliability
If TCP packets are intercepted and forwarded through a bi-directional tunnel by the previous access router, then TCP communication continuity is maintained, but network protocol complexity increases
Solution Approach 1:
The previous access router acts as a mediator that handles TCP packet interception and forwarding, centralizing the complexity in a single network element rather than requiring changes to multiple devices. This approach maintains TCP continuity while concentrating protocol complexity management.
Solution Approach 2:
The patent modifies packet routing parameters by intercepting TCP packets at the previous access router and changing their destination through the bi-directional tunnel. This parameter change approach maintains communication continuity by redirecting packets through an alternative path during handoff.
3Productivity
If the TCP window stops sliding during handoff due to lack of ACK receipts, then packet transmission rate decreases, but implementing traditional TCP handoff solutions increases handoff delay
Solution Approach 1:
The bi-directional tunnel is established in advance before handoff completion, preparing the packet forwarding path preliminarily. This allows TCP ACKs to be forwarded immediately when the mobile node reconnects, preventing the TCP window from stopping and maintaining packet transmission rate without incurring handoff delay.
Solution Approach 2:
The patent ensures continuous TCP packet forwarding through the bi-directional tunnel during handoff, preventing the TCP window from stopping. This maintains the continuity of useful action (packet transmission) without interruption, avoiding both handoff delay and transmission rate degradation.
Data Source
AI summary
A handoff apparatus and method in FMIPv6 for seamless TCP packet transmissions. The handoff method includes steps of intercepting by a previous access router certain TCP packets sent from a correspondent node to a previous temporary address of a mobile node; and creating a TCP ACK by the previous access router in response to the certain TCP packets and sending by the previous access router the created TCP ACK to the correspondent node every time the certain TCP packets are forwarded to a new access router through a bi-directional tunnel. The handoff method has an advantage in that the packet transmission rate can be secured at the same level as the mobile node stays still during the performance of the handoff of the mobile node since the previous access router instead of the mobile node creates and sends the TCP ACK to the correspondent node during the performance of the handoff of the mobile node.