Dectecting and analyzing network speed

[ljCharlie]

Recently we have our 10Mbps switch replaced with a 10/100Mbps switch. However, users experienced the speed has decreased instead of increasing. I actually feel that our network speed has decreased quite a bit. Is there a way to measure this? And if there is, how or what do I compare the data against? We no longer have the 10Mbps switch anymore so once I have the data and analyzed it, how do I know if the speed we get is normal or not? Currently I have used Ethereal, but I'm still not sure if this will do what I wanted it to do. Secondly, I'm not sure to analyze the data once I have the data from using the Ethereal program. Any suggestion or links to explanation or documentation is much appreciated!

ljCharlie

 

[plucnik]

Ethereal is a packet analyzer (and a nice freebie) that gives very specific info on the data flowing over the network. Are you on a Windows server? If so, I would try the Network Monitor that comes with Windows server to see where the heavy usage is. The monitor gives a little broader view of what's occuring.There may be a lot of broadcasts going out or one of the machines may have a bad NIC that won't negotiate up to 100 mbs. Try to isolate what's eating up the bandwidth with Network Monitor and then use Ethereal to analyze it.

 

[ljCharlie]

Thank you for the response. We have Windows 2000 Pro. If I use the Performance Monitor to monitor the network, what do I monitor and for how long? I don't believe it's the NIC or the cable because I was able to verify on the LAN connection that it is 100Mbps. The problem is many users felt that it's slower than when it was at 10Mbps and how do I verify that fact.

ljCharlie

 

[Bob Cerelli]

One not very techically elegant way is to simply copy a fairly large file or directory and time how long it takes. Using something with around 200-500 megs or so is good enough.

 

[ljCharlie]

That is a good idea; however, once I have that timed, what do I compare that number against?

Somehow it seemed that it's not the continous transmission of data that is slow...it seemed to be initial start of transmitting information that is slow. Once the transmission has started and going, it's not too bad.

ljCharlie

 

[Bob Cerelli]

You would compare the time on a 10 MB hub vs. the 100. I usually do this for customers before making the change so they can see the difference.

You also want to make sure the network cards are set for 100 MB Full Duplex. I kinda like setting them manually since the autodetect does not always work. Most of the times but not always.

 

[plucnik]

Great suggestions by Bob. I especially agree with his full duplex insight. To answer the network monitor question......I guess the "right" way to do it is to have some sort of a performance benchmark for comparison. But....you could just run the monitor for any amount of time and it will show "who's sending what where and how much". What I meant by looking for broadcasts is that the network "objects" send queries out on the line saying "hello, who's out there?" (usually more from the server, router and switch than the PC's). Unfortunately, if you have an unmanaged switch (without a network address), you won't really be able to tell what it's doing. Oh, one thing about the network monitor, it tracks by the MAC address of the objects so you'll have to resolve those to IP's or names (and save that file) for easier monitoring.