Traffic Shaping Node Capacity Estimation via Steady State Probe Packets
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Solution Overview
Problem
Existing methods for estimating available path capacity in data communication systems with traffic shaping nodes, such as those using token buckets, often result in overestimation due to the burst rate transmission of probe packets, which does not accurately reflect the average capacity.
Innovation Solution
The method involves sending setting packets to set the traffic shaping node in a steady state, allowing probe packets to be transmitted at an average rate, enabling accurate estimation of available path capacity by distinguishing between burst and average rate conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If probe packets are sent at high rate to measure available capacity, then measurement speed is improved, but the measured capacity is overestimated due to burst rate transmission
Solution Approach 1:
The patent applies preliminary action by first sending setting packets to establish a steady state in the traffic shaping node before sending the actual probe packets for measurement. This preliminary setup ensures that the traffic shaping node is in the correct operational state (steady state rather than burst mode), allowing the subsequent probe packet transmission to accurately reflect the average capacity rather than being skewed by burst rate transmission. The setting packets prepare the system in advance for accurate measurement.
2Measurement precision
If setting packets are sent to establish steady state, then measurement accuracy is improved, but measurement time is increased
Solution Approach 1:
The patent applies partial action by using a limited number of setting packets (e.g., 10 packets) rather than establishing steady state through extended periods or excessive packet transmission. This partial approach is sufficient to transition the traffic shaping node from burst mode to steady state, achieving the necessary measurement accuracy without requiring excessive time or resources. The invention finds the optimal balance point where a small number of setting packets achieves steady state without unnecessary delay.
3Measurement precision
If probe packets traverse the data transfer path during real-time operation, then available capacity is accurately estimated, but network traffic is affected
Solution Approach 1:
The patent applies local quality by making the probe packets distinguishable from normal network traffic through specific packet characteristics (such as IP precedence bits or packet markers). This allows the traffic shaping node to treat probe packets differently - specifically, to allow them to pass through at the steady state rate without blocking or dropping them, while other network traffic continues to be shaped according to normal QoS policies. This localized differentiation enables accurate measurement without disrupting overall network traffic flow.
Data Source
AI summary
A method of estimating available capacity of a data transfer path that transfers data between a sending and a receiving data communication node of a data communication system is disclosed. The method includes: sending one or more setting packets wherein the one or more setting packets is/are used to set a traffic shaping node arranged in the data transfer path in a steady state; transmitting, from the traffic shaping node, probe packets received from the sending node, towards the receiving node at an average rate for the traffic shaping node; providing, in response to traversal of the data transfer path by the probe packets, and during the real-time operation of the data transfer path, measured data for use in estimating the available capacity of the data transfer path; and estimating the available capacity of the data transfer path using the measured data from the probe packets.