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A popular recommendation from security providers is to ensure wireless networks achieve 'frequency separation' from other wireless networks.

What does 'frequency separation' mean in technical terms and what steps could an organisation take to achieve this?

A technical answer / link to an informative resource would be greatly appreciated.

KimberleyK
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2 Answers2

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Frequency separation addresses interference between an AP and other devices operating in an overlapping frequency. From a security perspective it supports the "availability" of the CIA triad. "Integrity" is not an issue since frequency separation deals with the layer 1 of the OSI model.

Long story short, you need to ensure that APs which cover overlapping areas are operating in different channels to eliminate interference (conflict) between them.

Sources:

  • "Wireless Networking: Know It All: Know It All" - page 347
  • "Certified Wireless Technology Specialist - Official Study Guide" - page 148
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Let's first understand basics about Wireless Radio Band

Wireless Networks works in ISM (Industrial, Scientific and Medical) Radio band, which is a part of radio spectrum.
ISM radio band is reserved internationally for unlicensed usage; Means anyone can use this radio band for setting up its wireless network.

In ISM radio band, frequency spectrum is reserved in two ranges -

  • 2.4 GHz
  • 5 GHz

Roughly, 80 MHz is reserved in 2.4 GHz band and 400 MHz is reserved in 5 GHz band (country-to-country this differs). In 2.4 Ghz band, we have 11 channels, out of those only 3 are non-overlapping. While, if we talk about 5 GHz band, we have 23 non-overlapping channels.

Now comes to your questions -
What does 'frequency separation' mean in technical terms and what steps could an organisation take to achieve this?

In wireless world, frequency separation means using non-overlapping channels. So, if you are using 2.4 GHz radio band, you have 3 non-overlapping channels; while in 5 GHz band, you have 23 non-overlapping channels.

About your first statement-
A popular recommendation from security providers is to ensure wireless networks achieve 'frequency separation' from other wireless networks.

This statement is no more relevant in present wireless world. If you are running WEP in your wireless network, and even if you are in different channel than your neighbour (or any other potential hacker), then chances are high that your wireless network is already screwed.

WPA2 (+802.1X) is the most secure protocol nowadays in wireless industry and a recommended one. Even if you are in same channel with any other user; then also, screwing up WPA2 is not easy.

To summarise, you will face interference if you are in same channel with your neighbour and this will reduce throughput and hence user experience. 'Frequency Separation' minimises the interference and hence high throughput and better user experience.

Hope this helps !!!

Gaurav Kansal
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  • This statement is no more relevant in present wireless world actually, it is still very relevant. The goal of security is threefold: Confidentiality, Integrity, and Availability. Achieving frequency separation is useful to reduce interference which can compromise Availability. – Lie Ryan Oct 22 '16 at 18:38
  • Even if i am on separate channel, an intruder (or sniffer) can sniff all the channels and can figure out that some communication is going on. Next step after figuring out is to find out, what is going in the medium, and this figuring out depends on the protocol i am using, be it WEP or WPA or WPA2. – Gaurav Kansal Oct 22 '16 at 18:43
  • you're talking still about C and I, which is what WEP/WPA/WPA2 mitigate. Even when using encryption, frequency separation is not irrelevant because encryption doesn't address A at all. – Lie Ryan Oct 22 '16 at 18:51
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    The attack scenario here is that you don't want an attacker to be able to disrupt your network remotely by attacking your neighbour which has weaker security and who shares the same channel with you. Frequency separation doesn't address local attacker with frequency jammer of course, for that you either need to do frequency hopping (which isn't available in consumer level devices) or just hope you have more transmit power than your attacker. – Lie Ryan Oct 22 '16 at 18:58