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How to tune your company's network

Posted on 1 Dec 2009 at 11:01

Steve Cassidy explains how to properly tune a business network

No sooner had I written a recent Ten Rules for Small Businesses article than I started tripping up over my own advice.

It seems that a lot of net guys out there have been bruised by users who cavalierly change the settings of their network cards and thereby converge upon the worst possible combination of parameters.

These bruised warriors are nursing such painful psychic wounds that my article provoked great outpourings of angst from them: first I said that properly up-to-date kit doesn’t need altering from its default settings, and second I suggested that in any case they weren’t being paid to fix mistakes their clients had made by fiddling in places where ignorant little mice really shouldn’t fiddle...

The technical basics supporting this advice are simple enough. If you have an unmanaged switch – and the vast majority of you do, even though I keep trying to tell you to spend a bit more for a managed one – then you may well discover that certain manually chosen settings in your network card’s setup will make your network traffic run slower than the default, while others will make it run faster.

My critics took the view that people should just leave the kit well alone unless they’ve had at least 20 years of experience

My critics, still smarting under their flagellant’s wounds, took the view that people should just leave the kit well alone unless they’ve had at least 20 years of experience (okay, I’m exaggerating, but only slightly). This reaction is based on their own experiences of course, where either their wretched users, or that misguided techie they’ve just replaced in a small business, had read some piece of advice and gone round applying it without any experimentation.

I now see that rashly throwing around words such as “experiment” or “tune” (which is what I did in the aforementioned article, space being short) and expecting users to live with the consequences may be a mistake. It only takes one breath to say “you need to tune your network”, and I suppose that’s why people jump to the conclusion that the tuning process itself should be equally brief. It’s not. I allow a couple of hours for a basic network tuning exercise, and longer if it’s a teach-in session.

To tune your network you need two fully representative PC workstations: ideally, these should be in factory-default-restored state with all patches and updates loaded, set up on the same switch (that alone can take a day: I expect in-house techies to be able to reach that starting point – if not, there’s a whole different conversation to be had), and your standard suite of applications should all be installed. Then one of the pair should have the vendor’s very latest device-specific drivers added for its LAN card, motherboard and any other specific peripherals. Only then does it make sense to begin the tuning process, which will require that you find or create at least three or four different sizes of file – roughly 10MB, 100MB and 1GB make a good starting place.

File copying

Each PC should copy these files down from the same file server and the machines shouldn’t do this copying at the same time. That’s the test suite, and various LAN card settings can be varied between each copy operation to see what effect they may have.

In certain cases, each time a parameter is altered the machine will have to be powered off – not just rebooted – to get the card’s firmware to act on the change, and in extreme cases with poorly behaved wake-on-LAN cards, you may have to physically pull the power cable out of the machine for the change to be accepted at the next power-up.

I hope my critics will agree that this is a good definition of a perfectly achievable test, but that it would have been impossible to spell it out in so many words in the space available, given that there were nine further rules to cover.

It saddens me to learn how many consultants keep encountering users whose efforts at network tuning resemble prodding a wasp’s nest with a stick, but that’s only a shadow of the sadness I feel on discovering that they don’t feel confident enough to charge extra for tackling such howlers. Lads, if your single-mouse-click remedy really does save the whole company then you shouldn’t be settling for your normal monthly retainer, but should be demanding a seat on the board.