Table Of Contents
Table Of Contents

Measuring Transmission Time

Goals

In this example we explore the packet transmission time statistics of network interfaces for wired and wireless transmission mediums.

INET version: 4.4

The Model

The packet transmission time is measured from the moment the beginning of the physical signal encoding the packet leaves the network interface up to the moment the end of the same physical signal leaves the same network interface. This time usually equals with the packet reception time that is measured at the receiver network interface from the beginning to the end of the physical signal. The exception would be when the receiver is moving relative to the transmitter with a relatively high speed compared to the propagation speed of the physical signal, but it is rarely the case in communication network simulation.

Packet transmission time is measured from the beginning of the physical signal encoding the packet leaves the network interface up to the moment the end of the same physical signal leaves the same network interface.

Packet transmission time is the time difference between the start and th end of the physical signal transmission on the outgoing interface.

Here is the network:

../../../../_images/Network9.png

Here is the configuration:

[General]
network = TransmissionTimeMeasurementShowcase
description = "Measure packet transmission time on the channel"
sim-time-limit = 1s

# source application ~96Mbps throughput
*.source.numApps = 1
*.source.app[0].typename = "UdpSourceApp"
*.source.app[0].source.packetLength = int(truncnormal(800B, 200B))
*.source.app[0].source.productionInterval = exponential(100us)
*.source.app[0].io.destAddress = "destination"
*.source.app[0].io.destPort = 1000

# destination application
*.destination.numApps = 1
*.destination.app[0].typename = "UdpSinkApp"
*.destination.app[0].io.localPort = 1000

# enable modular Ethernet model
*.*.ethernet.typename = "EthernetLayer"
*.*.eth[*].typename = "LayeredEthernetInterface"

# data rate of all network interfaces
*.*.eth[*].bitrate = 100Mbps

Results

TODO should the packet length be variable ? so the transmission time is not the same

Here are the results:

../../../../_images/TransmissionTimeHistogram.png
../../../../_images/TransmissionTimeVector.png

Sources: omnetpp.ini, TransmissionTimeMeasurementShowcase.ned

Discussion

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