A Parallel Flow Monitoring Technique That Achieves Accurate Delay Measurement

Abstract

In this paper, a parallel flow monitoring technique that achieves accurate measurement of end-to-end delay of networks is proposed. In network monitoring tasks, network researchers and practitioners usually monitor multiple probe flows to measure delays on multiple paths in parallel. However, when they measure an end-to-end delay on a path, information of flows except for the flow along the path is not utilized in the conventional method. Generally, paths of flows share common parts in parallel monitoring. In the proposed method, information of flows on paths that share common parts, utilizes to measure delay on a path by partially converting the observation results of a flow to those of another flow. We perform simulations to confirm that the observation results of 72 parallel flows of active measurement are appropriately converted between each other. When the 99th-percentile of the end-to-end delay for each flow are measured, the accuracy of the proposed method is doubled compared with the conventional method.

Algorithms for composing communication protocols of wireless sensor networks with random access

“…Such control is not necessarily related to a collision; it may also be due to external interference. In any case, the protocol should be maximally limited from unnecessary redundant information [1,2,4]. Limiting the protocol in time is also useful because of the energy savings that the node spends on radio transmission.…”

“…For example, let's turn to the solution of using a provisioning device that works with FSK modulation. Then the transmission signal from the sensor will look like, as shown in Figure 2, and will consist of sinusoidal waves with two different approximate frequencies 𝑓𝑓 � and 𝑓𝑓 � , corresponding respectively to 𝑓𝑓 � logical zero (0) and 𝑓𝑓 � logical unit (1). Changes in significant states from 1→0 and 0→1 occur in compliance with the continuity of the phase of sinusoidal waves with frequencies f. The continuation time of sequences 𝑓𝑓 � and 𝑓𝑓 � corresponds to the length of the protocol and is 𝑡𝑡 � .…”