802.11a—best migration path to higher speeds.
The advantages of 802.11a are numerous and obvious, but what of those corporations and institutions that have
already adopted 802.11b? Can they easily migrate to high-speed, high-capacity 802.11a wireless LAN connectivity?
Fortunately, the answer is that not only is there an easy migration to fast, robust 802.11a networking, but that
11a and 11b will be able to peacefully co-exist within the same organization, with users seamlessly switching
between systems as they roam.
802.11a is the easiest migration path to a higher speed wireless LAN because it operates in the uncongested
5 GHz frequency band. This means that it can be deployed alongside existing 802.11b installations without fear
of interference.
Some well-read managers may be aware of another wireless standard under development called IEEE 802.11g
that offers 54 Mbps speed. This standard is not ratified yet, so products are not yet available. The benefit touted
with 11g is that it offers backwards compatibility with existing 11b systems.
The downside to 11g is that it uses the same frequencies and same three channels as 802.11b in the 2.4 GHz
band. The result is interference between 11b and 11g systems, making them incompatible such that 11g cannot
be deployed simultaneously with an existing 11b network. This prevents network managers from adding users
who need higher speeds without first removing the entire original 11b network, even if low speed users will
continue to work wirelessly with their 11b client cards.
802.11a—achieving backwards compatibility with 802.11b networks.
While others may agree that 11a is a simpler migration to higher speed, they may wonder about compatibility
with 11b systems in other places. How do I connect to 11a at the office, and also connect simply and easily to
11b networks at home or in public hot spots at airports or cafes? Fortunately the answer to this question is not
to carry two wireless cards—an inconvenient solution at best. Dual-mode 802.11a/b client cards are already in
the pipeline ready for deployment. These cards function just as current laptop wireless networking cards do, but
have the ability to detect the wireless standard in use and automatically switch to that system. When a user
walks from an 802.11b cell to an 802.11a cell the card “sees” which system to use and makes the adjustment
on the fly.
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