TCP Traffic Management via Satellite PEP Window Adjustment
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Solution Overview
Problem
TCP traffic optimization is challenging in networks with high transit latency or packet loss, such as satellite networks, as standard TCP protocols are optimized for wired networks and lead to bandwidth wastage and congestion issues.
Innovation Solution
A Performance Enhancing Proxy (PEP) system adjusts and replaces window size advertisements in TCP signaling and traffic packets to match available satellite bandwidth, optimizing traffic flow and avoiding congestion by manipulating receive window sizes based on real-time link conditions and bandwidth availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard TCP protocols are used in satellite networks, then reliable endpoint-to-endpoint transport is achieved, but bandwidth wastage and congestion issues occur due to high transit latency and packet loss
Solution Approach 1:
The patent introduces a Performance Enhancing Proxy (PEP) as an intermediary device in the satellite network path. The PEP intercepts and modifies TCP window size advertisements between endpoints, acting as a mediator that optimizes traffic flow control. This intermediary adjusts the receive window size to match actual satellite link conditions, preventing bandwidth wastage while maintaining reliable transport through the high-latency satellite channel.
Solution Approach 2:
The patent dynamically changes the TCP receive window size parameter based on real-time satellite link conditions. The PEP modifies the window size advertisement in TCP packets to reflect actual available bandwidth and link state, rather than using standard TCP window sizing. This parameter adjustment prevents congestion and packet loss while maintaining efficient data flow through the satellite network.
2Productivity
If TCP window size is increased to improve throughput, then more data can be transmitted, but congestion drops occur due to traffic overrun in satellite networks
Solution Approach 1:
The patent implements a feedback mechanism where the PEP continuously monitors satellite link conditions, bandwidth availability, and traffic flow state. Based on this feedback, the PEP dynamically adjusts the TCP window size advertisement to match current network capacity. This feedback loop prevents traffic overrun by ensuring the window size never exceeds what the satellite link can reliably handle, thus avoiding congestion drops while maximizing throughput.
Solution Approach 2:
The patent makes the TCP window size dynamic rather than static. The PEP continuously adapts the window size advertisement based on changing satellite link conditions, bandwidth availability, and traffic patterns. This dynamic adjustment allows the system to optimize throughput under varying conditions while automatically preventing congestion drops when the link becomes saturated or experiences packet loss.
3Reliability
If traditional GEO satellite network protocols are used, then TCP performance is maintained, but overhead is excessive compared to LEO/MEO systems
Solution Approach 1:
The patent extracts only the essential TCP window size advertisement modification function from complex traditional GEO satellite protocols. Instead of implementing full GEO protocol stacks with their extensive overhead, the PEP selectively applies window size manipulation to TCP packets passing through LEO/MEO satellite networks. This extraction approach maintains TCP performance benefits while eliminating unnecessary protocol complexity and overhead specific to GEO systems.
Data Source
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AI summary
A terrestrial terminal enables communications, over a network connection through a satellite, between a local host of one or more connected local hosts and a remote host. The terrestrial terminal is configured to perform operations comprising: receiving, from the remote host, a network packet for the local host; obtaining, from the network packet, an included TCP segment; determining, from the TCP segment, a receive window size advertised by the remote host; computing, using one or more characteristics of the network connection, a target receive window size; comparing the target receive window size with the advertised receive window size; and in response to determining that the target receive window size is different from the advertised receive window size: modifying the TCP segment by replacing the advertised receive window size with the target receive window size, and forwarding the network packet with the modified TCP segment to the local host.