Adaptive Packet Sending Rate Control for Low-Latency Networks
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Solution Overview
Problem
Existing active congestion control mechanisms in communication networks require all devices to support a committed access rate (CAR) mechanism, which is not feasible on live networks, leading to congestion, increased delay, and packet loss when devices without CAR are present.
Innovation Solution
A data sending method that determines sending rates based on round-trip times (RTTs) and packet loss rates of probe packets to adjust transmission intervals, using a combination of passive and active congestion control to reduce congestion and delay, with feedback packets carrying ACK messages for fast retransmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active congestion control mechanism is used, then packet loss is reduced and delay is lowered, but all devices must support CAR mechanism which is not feasible on live networks
Solution Approach 1:
The patent implements feedback mechanisms by measuring RTT and packet loss rates of probe packets, then using this feedback to dynamically adjust the sending rate of data packets. The system continuously monitors network conditions and adapts the transmission rate based on observed congestion indicators, enabling effective congestion control without requiring CAR mechanism support on intermediate devices.
Solution Approach 2:
The patent changes the sending rate parameter dynamically based on measured RTT and packet loss rates. By adjusting this key parameter in response to network conditions, the system achieves congestion control adaptability across diverse network environments with different device capabilities, resolving the contradiction between reliability and device compatibility.
2Productivity
If sending rate is increased to improve transmission efficiency, then productivity increases, but congestion occurs on devices without CAR support causing packet loss
Solution Approach 1:
The system uses packet loss rate measurements as feedback to control the sending rate. When packet loss is detected, the sending rate is reduced; when packet loss is low, the sending rate can be increased. This feedback loop enables the system to maximize transmission productivity while maintaining reliability by avoiding congestion-induced packet loss on non-CAR devices.
Solution Approach 2:
The sending rate is made dynamic rather than fixed, allowing the system to adapt to changing network conditions. The rate fluctuates based on real-time measurements of RTT and packet loss, enabling the system to achieve high productivity during good conditions while maintaining reliability during congestion, effectively resolving the contradiction between these two parameters.
3Loss of time
If probe packets are sent at high rates to quickly determine sending interval, then time is reduced, but congestion and delay increase on the transmission link
Solution Approach 1:
The patent sends a limited number of probe packets at controlled rates to gather sufficient information for determining the sending interval, rather than continuously sending probes at maximum rate. This partial action approach achieves the necessary measurement in reasonable time without causing excessive congestion and delay on the transmission link.
Solution Approach 2:
The system uses periodic probe packet transmission at controlled intervals to measure RTT and packet loss rates. This periodic action allows the system to periodically update its knowledge of network conditions and adjust the data packet sending interval accordingly, balancing the need for timely information with the need to avoid congestion-induced delay.
Data Source
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AI summary
This application provides a data sending method and a communication apparatus, to reduce a data transmission delay. The method includes: determining a first sending rate based on multiple round-trip times RTTs, where the multiple RTTs include RTTs of a plurality of first probe packets sent at different sending rates, and the first sending rate is a sending rate corresponding to an RTT that is in the multiple RTTs and that is less than a first preset threshold; determining a second sending rate based on a plurality of packet loss rates, where the plurality of packet loss rates include packet loss rates of a plurality of second probe packets sent at different sending rates, and the second sending rate is a sending rate corresponding to a packet loss rate that is less than a second preset threshold; and sending a third probe packet at a third sending rate, where the third probe packet is used to determine a sending interval of a data packet, and the third sending rate is a smaller value of the first sending rate and the second sending rate.