# Θεματολογία δικτύου > 5 GHz >  802.11a--Fast Wireless Networking

## wiresounds

Πηγή: extremetech

Are you ready for fast wireless networking? Well, it's (almost) ready for you. We got our hands on the first shipping 5GHz, 54Mbps 802.11a wireless networking adapter PC Cards from Proxim, and beta adapters from two other vendors. We also received a reference design 802.11a access point and pair of adapters from Atheros Communications, Inc., the company that produces the chipsets that will be used in all of the first round of 802.11a products that come to market. We completed initial objective and anecdotal performance testing and found that, even with many beta drivers for most products, we can make general observations about 802.11a performance. The quick and dirty answer: we found 802.11a to be almost five times faster than 802.11b (the current hands down wireless network standard) *at short distances*. 

802.11a and 802.11b aren't compatible because they operate on different frequencies, so a 2.4 GHz 802.11b access point, for example, won't work with a 5 GHz 802.11a network card - but the two standards can certainly co-exist. On our test network we're currently running both 11a and 11b, using separate access points and multiple clients for each, with both wireless access points connected to our wired network and router-based DHCP server. In this setup, all of our computers (wired, HomePNA, and both types of wireless) can see each other and share resources including broadband Internet access. 

So 802.11a is here, the first products are about as fast as expected, and during the next 6-9 months we'll see a whole slew of new consumer- and enterprise-level wireless network products based on this new standard. Will you throw out your existing 802.11b equipment to replace it with 802.11a? Probably not. Can you add 802.11a to an existing 802.11b wireless network? Sort of, but it will be like starting over, at least until bridging products are available (figure early- to mid-2002). If you're about to install a new wireless network which way should you go? If you need it right now you should stick with 802.11b because the 11a products are just trickling out, and right now they're about twice as expensive as comparable 11b products - but if you can wait three or four months, say until February or March of 2002, product availability and selection should be better, and prices should start to come down at least a little bit, and in that case we believe you should give serious consideration to 802.11a. 

Finally, you may be wondering about the other recently approved high-speed wireless standard 802.11g, and what it's all about and how it compares to 11a and 11b. Check out our sidebar that explores 802.11g in detail.

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