Frequently Asked Questions
Q1. How do you measure the performance of my connection?
To measure the performance of your connection you must download and install a small program on your computer. This program runs in the background (it will not disturb other work on your computer) and monitors every piece of data that is sent across your connection. The applet calculates statistics from the data that it observes and sends these statistics back to our central server where further analysis is performed and the results are made available for you to view.
Q2. Does that mean that you know what sites I have been visiting?
Not directly. The information that the measurement applet sends back to our
server is aggregated so that individual connections are not identifiable.
The statistics are collected for each /24 netblock that you communicate
with. A /24 netblock contains 254 different computers. It is not possible
to identify an individual computer out of the 254 from the data that is
reported back to our server. These are further aggregated each day by looking
at network prefix data from a BGP feed and grouping together measurements made
to netblocks that are nearby to one another.
The statistics that are reported back to our server are numbers that the
application has observed from watching the connection. They do not contain
any of the actual data or information (such as site or page names) that was
transferred to/from your computer. The measurement application will try to
guess what sort of data was being transferred in order to provide a breakdown
of the different traffic types involved, but won't record any specific
information about what your traffic is.
To view the statistics from your individual connection you must know
your username, which allows you to keep them private or choose to share
your graphs with others. None of your personal information is viewable
even to those you share graphs with as you must be logged in with both your
username and password to have access. Your individual statistics may be
combined together with other data to use in aggregated performance reports
that will not individually identify your connection.
Q3. So exactly what information is being sent to your server?
For each /24 netblock that a data packet is sent to or received from, the following statistics are calculated and reported to our server.
- Number of normal (in-order) packets
- Number of out-of-window packets
- Number of retransmissions
- Number of packets reordered by the network
- Number of packets duplicated by the network
- Number of packets unable to be categorised
- Latency (RTT) estimation
- Hopcount (TTL) estimation
- Outgoing/Incoming throughput estimation
- Outgoing/Incoming 3 second peak throughput estimation
- Size of packets not matched to a session
- Number of TCP SYN packets observed
- Number of TCP FIN packets observed
- Number of TCP RST packets observed
- Number of Destination Unreachable errors observed
- Incoming/Outgoing WWW byte count
- Incoming/Outgoing Mail byte count
- Incoming/Outgoing Filesharing byte count
- Incoming/Outgoing Games byte count
- Incoming/Outgoing Chat byte count
- Incoming/Outgoing unclassified byte count
Q4. What do you do with the data you collect?
Your data is available to you in full for one week from collection via the Nettest URL you are given at sign-up. Individual data will not be published or shared with any one. After a day the data for each of the netblocks that you have been communicating with gets aggregated into even larger blocks based on their address and position within the network. After one week this is further consolidated into fewer time periods of longer length, which loses some resolution but also makes personal traffic harder to identify and allows us to store data for much longer. We aggregate and statistically analyse the data and the results of that process are available via the public Nettest pages. We aim to publish reports on Internet performance using the aggregated data.
Q5. How much does this cost and how long do I sign up for?
Use of nettest is free. You supply us with your data and we provide a comparison with the aggregate statistics so you can tell how well your ISP is doing. No money changes hands. You can use nettest for as long as you like and can stop at any time simply by un-installing the software.
Q6. I have a small data-cap. How much traffic does this use?
It depends on how much you are using your Internet connection. The more
sites you visit on the Internet the more data there is to report back to
the server. A report is generally sent to the server every 5 minutes.
The report data is compressed before it is sent back to our server to minimise
the amount that needs to be transmitted. However this also means that we don't
know for sure how much data needs to be sent each time, as the compression
ratios can vary.
In a worst case scenario, the report for each netblock requires 368 bytes
of data. If we assume that every 5 minutes there are 20 netblocks to report
back to the server then that is 7.2kB of data per report, which in turn is
86kB of data per hour and 2MB of data per day. This works out to a total
of roughly 60MB of report data per month. Compression generally improves it
to less than half that.
Q7. Where can I find more information about how this works?
The best place to start would be the nettest trac. This site provides a wiki and bug tracking functionality, as well as an interface to the nettest Subversion repository so you can explore the code to see exactly how we perform the measurements. Documentation to support the code is regularly added to the wiki. This is also the place to make bug reports and feature requests.
Q8. Who runs this site?
This site and the programs that are used to collect data for it was developed by Perry Lorier, Matt Brown, Brendon Jones of the WAND Network Research Group in the Department of Computer Science at the University of Waikato and Zach Bagnall. If you have any questions, comments or other feedback please send them to Brendon Jones (bcj3 at cs dot waikato dot ac dot nz). You could also visit the bug tracker and wiki at http://wand.net.nz/trac/nettest and help contribute!