Edge Router RWND Modification for 5G Buffer Bloat
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Solution Overview
Problem
Next Generation mobile networks, such as 5G, face challenges with congestion control due to high capacity millimeter wave radio links, leading to buffer bloat and increased retransmission rates, which existing protocols like TCP struggle to manage effectively.
Innovation Solution
An active congestion control scheme that modifies the receiver advertised window size (RWND) based on traffic shaping policy parameters, implemented at edge routers, to reduce data sending rates without increasing packet dropping or retransmission rates, using a congestion control agent that adjusts the RWND according to maximum round trip delay time (RTT) and throughput (Rate) values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If existing TCP congestion control protocols are used in Next Generation mobile networks with high capacity millimeter wave radio links, then data transfer rates can be increased, but buffer bloat and retransmission rates increase
Solution Approach 1:
The congestion control agent performs preliminary actions by modifying the receiver advertised window size (RWND) in advance based on traffic shaping policy parameters (maximum RTT and throughput Rate) before congestion fully develops. This proactive adjustment prevents buffer bloat and excessive retransmissions by controlling the sender's data transmission rate ahead of time, rather than reacting after congestion occurs
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring network conditions and using traffic shaping policy parameters to dynamically adjust the RWND. The congestion control agent receives feedback about maximum RTT and throughput Rate, then modifies the RWND accordingly, creating a closed-loop control system that adapts to changing network conditions and maintains optimal performance
2Productivity
If data transmission rates are increased to utilize high capacity millimeter wave links, then network throughput improves, but congestion and packet dropping increase
Solution Approach 1:
The invention changes the RWND parameter dynamically based on traffic shaping policy parameters. By modifying the RWND (receiver advertised window size) according to maximum RTT and throughput Rate values, the system adjusts the effective data transmission rate to optimize network throughput while preventing congestion and packet dropping through controlled parameter modification
3Loss of energy
If TCP congestion control mechanisms are applied to maximize link utilization, then bandwidth efficiency increases, but packet dropping and retransmission rates increase
Solution Approach 1:
The congestion control agent acts as an intermediary between the TCP protocol and the network. It modifies the RWND parameter that TCP uses for congestion control, translating network conditions (maximum RTT and throughput Rate) into appropriate window size adjustments. This intermediary function allows TCP to maintain its bandwidth efficiency while preventing excessive packet dropping and retransmissions through controlled window size modification
Data Source
AI summary
A network device receives, from a congestion controller, traffic policy information associated with a data stream between a sender and a receiver, where the traffic policy information includes a maximum round trip delay time (RTT) and a maximum throughput rate (Rate). The network device obtains a receiver advertised window size (RWND) for the receiver for the data stream. The network device modifies the RWND based on the RTT and the Rate to produce a modified receiver window size (RWND′) and sends the RWND′ to the sender for use in controlling congestion on the data stream between the sender and the receiver.