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Apr 29 2009   12:25PM GMT

Did you see this? - Free Wireless LAN planning, deployment and management tools



Posted by: Troy Tate
tools, toolkit, wi-fi tools, network analysis, performance analysis, performance monitoring, wlan, 802.11, free, throughput, network throughput, throughput testing

Xirrus is a WLAN equipment manufacturer. They have some very cool products and if you have not checked them out and are looking for installing, adding or replacing any WLAN network gear, then I suggest you take a look at their offerings before making a decision.

Xirrus has a page on their website where they offer some cool free tools for planning, deploying and managing wireless networks. The tools will work on any 802.11 wireless network as well as on wired networks. Some of the tools available include:

Xirrus Wi-Fi Inspector
The Xirrus Wi-Fi Inspector is a powerful tool for managing and troubleshooting the Wi-Fi on a Windows XP or Vista laptop. Built in tests enable you to characterize the integrity and performance of your Wi-Fi connection.

Xirrus Wi-Fi Monitor Gadgets/Widgets
The Xirrus Wi-Fi Monitor allows you to monitor your Wi-Fi environment and connection in real time from your desktop in an easy-to-use mini-application. Nine different color skins allow you customize the Wi-Fi Monitor to your desktop

Iperf
Iperf is an easy to use and very popular tool that every IT professional should have that measures maximum throughput. Iperf provides you the data to tune TCP and UDP characteristics. Iperf reports throughput, delay jitter, and datagram loss in easy to understand tables and graphs. You can run Iperf from and command line or a GUI interface.

Qcheck
Qcheck is a must have and handy tool for any IT professional. It does much more than the traditional “ping” command

Other tools are available on this excellent website. I recommend that you take a few minutes, review the offerings and add to your toolbox those tools of value to you.

Thanks for reading and let’s continue to be good network citizens.

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Mar 6 2009   4:45PM GMT

Network speed & capacity are NOT the same



Posted by: Troy Tate
capacity, throughput, network speed, bandwidth, network band

There is often a misunderstanding of what network speed is versus capacity. The speed of data transfer is not just a function of the capacity (bandwidth) of the link, but of the distance between the endpoints. To find distances: Go to http://www.infoplease.com/atlas/calculate-distance.html to get distances between locations.

Considerations about the impact of latency and network throughput:
Networks do not transfer data in a continuous stream, as many people think, but in small packets. The server sends a packet to your computer, which sends an acknowledgement back (TCP/IP protocol). Upon receipt of the acknowledgement the server sends the next packet. This is called handshaking, it’s a little game of ping-pong.

The speed of light is 299792 kilometers per second. The maximum number of ping-pongs per second is therefore 299792 divided by twice the distance between you and the server. If the server is 1000 kilometers away that’s 149 ping-pongs per second. Every ping-pong is 1 packet, so if the packet size is 1 bit the server can only send you 149 bits per second. The speed of the network is immaterial, even a gigabit network cannot break the speed of light. The server is not sending data while waiting for the acknowledgement, waiting means less throughput, so the speed is reduced because of the distance. The further away,
the lower the speed.

Here’s some information that I came across but do not know the original source that will also help explain this situation.

Would you say that a Boeing 747 is three times “faster” than a Boeing 737? Of course not. They both cruise at around 500 miles per hour. The difference is that the 747 carries 500 passengers where as the 737 only carries 150. The Boeing 747 is three times bigger than the Boeing 737, not faster.

Now, if you wanted to go from New York to London, the Boeing 747 is not going to get you there three times faster. It will take just as long as the 737.

In fact, if you were really in a hurry to get to London quickly, you’d take Concorde, which cruises around 1350 miles per hour. It only seats 100 passengers though, so it’s actually the smallest of the three. Size and speed are not the same thing.

NOTE: In the internet world, there is no such thing as a Concorde. Data speed is limited to the speed of light. The speed of light in a vacuum is ~300,000 km/sec. – p.s. The Concorde jet service ceased operations in 2003  http://en.wikipedia.org/wiki/Concorde)

On the other hand, If you had to transport 1500 people and you only had one plane to do it, the 747 could do it in three trips where the 737 would take ten, so you might say the Boeing 747 can transport large numbers of people three times faster than a Boeing 737, but you would never say that a Boeing 747 is three times faster than a Boeing 737.

That’s the problem with communications devices today. Manufacturers say “speed” when they mean “capacity”. The other problem is that as far as the end-user is concerned, the thing they want to do is transfer large files quicker. It may seem to make sense that a high-capacity slow link might be the best thing for the job. What the end-user doesn’t see is that in order to manage that file transfer, their computer is sending dozens of little control messages back and forth. The thing that makes computer communication different from television is interactivity, and interactivity depends on all those little back-and-forth messages.

Thanks for reading and let’s continue to be good network citizens.

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Feb 27 2009   7:41PM GMT

Did you see this? - Internet Measurement Testing tools



Posted by: Troy Tate
network testing, network, testing, toolkit, research, throughput, analysis, Performance, performance monitoring

There will always be some user saying “the internet is slow”. There are many resources out there to test internet connections. The Measurement Lab is one I came across the other day. There are several useful tools under this page. Some of the tools and descriptions are listed below. Maybe one of these will be useful to you or your users some day. Just remember you heard about it on IT-Trenches! Thanks for reading and let’s continue to be good network citizens.

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