Wireless Networking

One common confusion relates to the variety of wireless networking options available and what the available options are. Pretty all of today’s wireless networking technologies are call 802.11x where x is a letter. The first six characters are not that important, and while the final letter is vitally important. The common technologies are 802.11A, 802.11B, 802.11G, 802.11N. The differences between these technologies are substantial.

First, you should be aware that all performance specifications provided by any of these standards are woefully overstated. Generally you will see substantially less bandwidth than promised by the standard. That said, here are the various standards and performance and radio frequency used:

  1. 802.11A – 54 Mb/sec, 5 GHz
  2. 802.11B – 11 Mb/sec, 2.4 GHz
  3. 802.11G – 54 Mb/sec, 2.4 GHz
  4. 802.11N – 540 Mb/sec, 2.4 or 5 GHz

The first thing that you should notice is the frequency differences between the standards. The first standards were A and B and they differed by both bandwidth and frequency. At the time, there was a question about which would prevail given the performance trade off. The G standard was released to solve the performance issues of B and leverage 2.4 GHz. The future standard is N which will bring an entirely new level of performance.

The other issue is that initially wireless cards only worked with A or G and not both. At the time there was a big question about which of the two technologies would prevail. Today there are cards that can do both frequencies, but it does not really matter since the 2.4 GHz technologies prevailed and A is seen infrequently.

As you look at the above performance numbers, you should always remember that they are overstated. I just ran some specific tests to illustrate. (Note all tests were running using the iPerf utility and each performance run was completed twice.)

 
Performance Spec
Actual
802.11G 20 Feet
54 Mb/sec
16.5 Mb/sec
802.11G 2 Feet
54 Mb/sec
20.6 Mb/sec
100 Base-T (wired
100 Mb/sec
93.7 Mb/sec

As you can see, the wireless standards underperformed their specs. It is also interesting to compare them to wired which is spec’d at approximately 2x the performance of wireless. Yet even with that spec, we saw performance that was almost 5x faster than wireless. A very big difference.

What should I buy?
The industry has standardized on 2.4 GHz technologies and so must customers are buying 802.11G wireless devices today. This is the safe choice and is recommended.

Should I buy 802.11N since faster is usually better?
The clear answer here is no. The issue is that the N standard has not been ratified by the standards thus it is unclear if N products shipping today will be compatible with the final standard. Thus if you purchase a unit today you not only pay a premium, but you run the risk of your hardware becoming obsolete and not supporting the standard. This particularly important since in the future it is likely that this technology will be embedded in laptops.

If I have 802.11B is vitally important that I upgrade to G?
The typical answer is no unless you have very bandwidth intensive applications. I find B/G wireless to be more than adequate for every day use. The only issue is transferring large files. I sometimes copy photos across the network and notice a major performance degradation with wireless. (I use G and B would likely be even more painfully slow.) If you are working with large files over the network, you are better off sticking with wired than trying to use any of the wireless standards. I would consider upgrading to N once the standard is ratified as that technology looks like it will bring new levels of wireless performance that were previously unattainable.

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