Thursday, June 16, 2011

Things Seem Slow... Back to Basics on Troubleshooting

With school out for a brief time, I've talked to several districts about various projects and have found more than one that has had concerns about network speed and throughput. Any 'tech at heart' loves this type of challenge, though getting to the bottom of the issue(s) can be a frustrating process. Perhaps for my own benefit as much as anyone else's, I am typing random thoughts and suggestions in the event that you're working through problems of a similar nature.

Get a baseline - On some of our networks, this is a challenge. For now, let's just assume that "the Internet is slow" is the gist of your issue. You need to have a feel for what the normal browsing experience should be in your environment. You need to know the bandwidth capacity of your outgoing circuit(s). You need to be aware of the network routes and devices that are traversed as Internet traffic leaves the workstation and makes its way to the Internet. Are you wireless or wired? Are you passing through gigabit ports, slower wired ports, N-series wireless versus B/G or B? Do you pass through Internet filtering solution(s)? All of this needs to be determined and you can take a few samples of Internet browsing from the problem stations or stations in a similar configuration.

Know your 'best case scenario'
- When I'm helping a district with thhttp://www.blogger.com/img/blank.gifis issue, it's nice to be able to set a station to bypass any Internet filter and to connect via wire to a point as close to your Internet connection as possible. If you can take quite a few hops and devices out of the loop, you can then determine if the speed issue is related to the devices you manage or if you have a larger problem with your provider.

Pick a few reliable sites/tools and stick with them
- Often, I'll browse to a news site as a test since several images, ads and banners need to load. I also use sites like Speedtest.net to get an actual bandwidth readout. Note, though, that the figures you see here can vary based on several factors, including other traffic on your own network, delays or capacity issues on the testing site's end, etc. That said, if you run a test several times from the same facility, it may give you a general idea of what throughput can be expected.

Make sure you know what you're troubleshooting - I'm writing this from the perspective of Internet access being slow. Sometimes, the user may be reporting slow Internet from their workstation that has problems like malware, limited hardware capacity or poor connectivity. Veterans of the industry can tell you that it could be any number of other problems when someone simply says that 'things are slow'. It could be one particular program that they use. They could be clicking the wrong icon. If you're chasing your tail, have the user show you their problem or perhaps at least get a screen capture of an error message. Basic stuff, I know, but how many times have technicians rushed to the super-technical layer of troubleshooting only to find that a patch cable was removed?

Know your own environment as best you can
- This is a challenge if you're working with limited staff as many school district tech departments often are. Suppose that your speed issue is definitely related to your Internet filter. Do you have a support relationship with the vendor? Is there someone you can leanhttp://www.blogger.com/img/blank.gif on for suggestions or other support? Do you have a firm grasp of how the users authenticate and are processed by this device? Is there an alternate configuration that might increase speed? (I mention this because many of these devices have different installation methods that can offer better throughput, better security or other enhanced capabilities.)

Can you look at the traffic - I'll end this post on a topic that isn't basic at all, but it can be an option. A network protocol analyzer like Wireshark can be used (with appropriate port mirroring) to capture traffic on a portion of your network. I'm not an advanced user of this type of tool, but the capabilities are getting better and you may simply need to confirm if traffic is ever leaving the network or if it's entering the network in a timely fashion. Without being an expert, seeing timestamps on network packets might help you determine where a delay could be.

The ramblings will continue at a later time... take care!
[image:Library of Congress]

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