Thursday 30 January 2014

2.4GHz/5GHz (802.11n)

802.11n builds upon previous 802.11 standards by adding Multiple-Input Multiple-Output (MIMO), which employs multiple transmitters and receiver antennas to increase data throughput. 802.11n can have up to eight antennas, but most of today’s access points use four. These are sometimes referred to as smart antennas, and if you do have four of them, two would be used for transmitting simultaneously with the other two receiving simultaneously. This setup would allow for much higher data rates than 802.11a/b/g. In fact, the marketing people claim it will provide about 250Mbps, but personally, I’m not buying it. I just don’t believe that’s what our actual throughput levels can be, and even if what they’re saying is true, exactly how would that help if all you’ve got is a 1 or 2Mbps cable or DSL connection to the Internet?

Keep in mind that the 802.11n standard hasn’t yet been ratified and isn’t expected to be until sometime in 2008—maybe later. This means that the products on the shelf today are proprietary,
and they are called “pre-N” products.

With all this in mind, let’s move on and take a look at Cisco’s solution to the growing wireless market.

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