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NetVanta 160 Series Wireless Configuration Guide Introduction to Wireless Technology

WLAN Standards

Wireless technology uses standards of IEEE 802.11, namely 802.11b, 802.11g, 802.11a, and 802.11n for

communication. Both the NetVanta 160 and 161 APs have two radios: one for receiving and transmitting

on 2.4 GHz and one for 5 GHz transmissions. The 2.4 GHz radio supports 802.11b/g/n standards, and the

5 GHz radio supports 802.11a/n standards. The decision of which radio and standard to use should be

based on a particular network’s needs. The standards are described in the following sections.

802.11b

802.11b is the earliest version of the 802.11 standard. In North America, 802.11b supports channels 1

through 11, which can be divided into three non-overlapping, non-interfering channel sets (channels 1, 6,

and 11). This allows three 802.11b APs to operate in close proximity without interference.

802.11b supports rate shifting bandwidths of 1, 2, 5.5, and 11 Mbps operating on the 2.4 GHz frequency.

The 802.11b signal range reaches approximately 100 meters in an unobstructed area and approximately

meters in an office environment.

Points to remember when considering the use of 802.11b are that (1) the frequency it uses is potentially

crowded by the use of other APs, cordless phones, and microwaves; (2) its speed capabilities are the lowest

of the WLAN implementations; and (3) it does not allow for more than three non-overlapping channel

assignments, thus restricting the number of users, as well as the data rate available.

802.11g

802.11g works on the same band as the 802.11b (2.4 GHz), but it operates at the higher data rate of

Mbps. 802.11g hardware is operable with 802.11b hardware; however, the presence of 802.11b

participants in an 802.11g network significantly reduces the speed of the network.

The 802.11g signal range is approximately 100 meters in unobstructed areas and approximately 75 meters

in an office environment.

One advantage to using 802.11g is that it has a higher data rate than the 802.11b, which provides more

bandwidth per user. Something to keep in mind with the 802.11g is that, like the 802.11b, its frequency can

be crowded by the interference of other APs, cordless phones, and microwaves.

802.11a

The 802.11a standard operates in the 5 GHz band, and provides 12 non-overlapping channels which are

separated into three ranges. The lowest range is 5.15 to 5.25 GHz, which allows four non-overlapping

channels; the middle range is 5.25 to 5.35

GHz, which also allows for four non-overlapping channels; and

the highest range is 5.725 to 5.825 GHz, which is used for outside point-to-point or point-to-multipoint

applications. Each range has its own regulated power and antenna requirements.

The 802.11a standard is inoperable with either 802.11b or 802.11g. The 802.11a uses a higher band

frequency than the 802.11b/g, so there is less interference to contend with. The 802.11a also provides more

total bandwidth, which allows more bandwidth per user.

The 802.11a signal range is approximately 50 meters in an unobstructed area, and approximately 25 meters

in an office environment.

Points to remember when considering the use of 802.11a include the fact that the higher frequency is more

easily absorbed by less dense objects, such as walls and ceiling tiles. Also, for larger coverage areas the

power input to the mobile device’s radio must be higher, resulting in reduced battery life and mobility

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ADTRAN NetVanta 160 Manual de usuario Pagina 3