Policing Network Traffic

What to do when network traffic threatens service speed and quality

Chris CahoeAs an enterprise network engineer at Ball State University (IN), Chris Cahoe has seen the university network evolve into an ISP for the campus community. On the front lines of network management at BSU, Cahoe has wrestled with performance problems such as latency, packet loss, and bandwidth issues that frustrate users across the campus and precipitate demands for improved services. But his strategies for network optimization have allowed the university to deliver fast, reliable connections to internet-based services without major investments in new infrastructure. How does he do it? Here, Cahoe offers his Top 10 practical tips for better network traffic management.

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10

Monitor and baseline your network; get to know it well.

  • Knowing your network is the key element of a good management strategy.
  • Familiarity with your network will become your best management tool.
9

Maintain long-term graphs of latency, jitter, and packet loss.

  • Gone are the days of simply monitoring whether the network is up or down.
  • Keep detailed records as proof of proper network management.
8

Don't allow network links to become saturated by traffic from any single part of your organization.

  • Define maximums and minimums for traffic that traverses links that have limited capacity.
  • If links become saturated, make sure everyone gets a fair slice of the pie.
7

Subdivide network traffic by type of user or device.

  • Create maximum and minimum throughput priorities for user groups such as academic users, residence hall users, or data center devices.
  • Make sure low-priority users can't overrun higher-priority devices and vice versa, while competing for bandwidth to the commodity internet.
6

Prioritize traffic as real-time or non-real-time.

  • Do not prioritize based on the perceived "importance" of the application.
  • An H.264 packet that is two seconds late is useless for streaming video; an e-mail that is two seconds late is still an e-mail!
5

Create contingency plans that address external outages.

  • Make sure your network is multi-homed; use multiple providers.
  • Be ready to alter your users' bandwidth priorities when your internet capacity becomes drastically reduced during an outage.
4

Give users the option to secure their traffic over the wired and wireless networks.

  • Encryption might not always be necessary, but make sure the capability is there.
3

Limit or block protocols that under normal circumstances shouldn't be used.

  • Just because the network can transmit all types of traffic doesn't mean it should.
  • Bot-infected computers could be using up bandwidth you paid a pretty penny for.
2

Watch out for end devices with abnormally high numbers of connections or connection rates.

  • If a device has connections that number in the thousands, and it's not a server, it's time to start placing bets on just how many viruses the device has.
1

Plan ahead for network growth.

  • If anything is a certainty, it's that bandwidth requirements will increase each year.
  • Don't be caught off guard by next year's demands!

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