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IEEE · Radio & mobile networksCurated

IEEE 802.11b: Wi-Fi at 11 Mbit/s

Summary

On 16 September 1999 the IEEE Standards Board approved the 802.11b amendment, which sped up Wi-Fi in the 2.4 GHz band from 2 to 11 Mbit/s. This made wireless networks fast enough for everyday use for the first time, and cheap cards and access points turned them into a mass product within a few years. The standard shaped how Wi-Fi works to this day, but also brought the weak WEP encryption into living rooms.

What 802.11b changed

The original 802.11 standard of 1997 managed 1 to 2 Mbit/s. 802.11b used the same 2.4 GHz band and the same CSMA/CA access method but reached up to 11 Mbit/s with a new modulation scheme. That was enough for the DSL connections of the time and for file transfers on the home network.

Because channels in the 2.4 GHz band overlap, only three networks fit side by side without interference, typically on channels 1, 6 and 11. Microwave ovens, Bluetooth and neighbouring networks share the same band. The included WEP encryption was considered broken from 2001.

Ideas

  • A standard only succeeds through cheap devices.
  • The 2.4 GHz band is free to use and therefore crowded.
  • Only three non-overlapping channels limit dense wireless networks.
  • Weak encryption stays in devices for years because nobody replaces them.

Insights

  • 802.11b shows the typical path of a network standard: speed first, then adoption, and only after that security. WPA came in 2003 as a stopgap, WPA2 in 2004.
  • Many problems of today’s Wi-Fi, from crowded channels to old devices with weak encryption, originate here.

Facts

  • Approved on 16 September 1999 by the IEEE-SA Standards Board.
  • Maximum data rate 11 Mbit/s in the 2.4 GHz band, access method CSMA/CA.
  • The content was later incorporated into the IEEE 802.11-2007 standard.

References

Remarks

  • The IEEE product page for 802.11b is no longer available; the approval date is on the cover page of the standard.

Recommendations

  • In the 2.4 GHz band, only use channels 1, 6 or 11.
  • Separate devices that only support WEP or WPA from the rest of the network or replace them.

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