Center for Applied Internet Data Analysis
projects : ark : statistics

Archipelago (Ark): CAIDA's active measurement infrastructure serving the network research community since 2007.

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# dtw2-us

MERIT

Ann Arbor, MI, US (72)

IPv6 data used (switch to IPv4)

### CCDF of destination RTTs

• percentile 10th 25th 50th 75th 90th
RTT (ms) 27.081 56.742 113.288 156.681 232.085
Use the following link to download the data used to render this graph in ASCII, comma-separated values format here: (CSV output)

### Description

This graph shows the complementary cumulative distribution function (CCDF) of round-trip times (RTTs) to the destination host.

### Motivation

By showing the distribution of RTT values to all responding destinations, we can get a sense of how varied the speeds are for connecting to different points in the Internet.

### Background

The complementary cumulative distribution function shows the fraction of collected data points that are greater than a given value. This is backwards from how percentiles are given, as those show the percentage lower than a given value. On this graph, you would find the 80th percentile at the 0.2 Y value. The round trip time of a probe is the time (in milliseconds) that it takes for a packet to be sent from an Ark monitor to a destination and for that destination's response to be received by the monitor. Therefore, no RTT values are recorded when a probe does not reach a destination.

### Analysis

When the CCDF graph has a nearly vertical dropoff point, that indicates that RTT values fall within a narrow range. This tends to mean that a bottleneck exists within the monitor's connectivity that dominates over individual destination path variation. A more gradual curve, on the other hand, indicates greater variability in the response times of destinations, which tends to scale directly with the path length distribution.