Good day, I'm Brian Ferrill, and welcome to PACE-IT's session on troubleshooting wireless networks part II. Today, I'm going to be discussing
wireless environmental factors. Then, we are going to conclude with wireless standard related
factors. There is a whole lot of ground to cover, so let's go ahead and begin this session.
Of course I'm going to begin by talking about wireless environmental factors.
When planning and setting up a wireless network, quite often, environmental factors that may
impact the wireless network are disregarded. It is easy to get distracted by all the moving
pieces of the wireless network, as in the SSID configuration, encryption, and which
standards to use. Dealing with these often leads to overlooking factors in the environment
that may impact the quality of the planned network. To get the most out of a wireless network, these factors need to be taken into consideration,
as they can have a major impact on the overall quality and performance of the installed network.
We don't think about it very often, but building materials can influence wireless networks.
A wireless network works by sending and receiving radio frequency waves across a given area.
Anything that can interrupt the signal or change the path of the waves can create a
problem in the network.
This is called signal bounce. The signal may return to the wireless
access point out of phase, leading to poor performance or dropped packets.
Alternatively, the signal may end up being bounced into areas where coverage was not
planned, leading to a security issue or an interference issue with other wireless networks.
Some building materials of concern include concrete walls, metal studs, and window films,
particularly window tinting with a metallic content. When evaluating environmental factors, it is important to consider more than just the
building materials. All hard surfaces have the potential to create an out-of-phase or
bounced signal, including office furnishings and file cabinets. Using a wireless analyzer
and wireless survey tools during the planning stage of a wireless network will lead to better
placement of the wireless equipment, which, ultimately, leads to a better performing network. Let's move on to some wireless standard related factors. First up is wireless standard compatibility. Not all of the 802.11 standards are compatible
with each other.
This is partially due to the RF frequencies that are used, with the
most common frequencies being the 2.4-gigahertz or the 5-gigahertz radio frequency band. The
problem with compatibility can also be because of the type of modulation that is employed.
Modulation is the encoding of information to be placed on a carrier wave. It's employed
to put the signal on the network. The most common forms of modulation are orthogonal
frequency division multiplexing, OFDM, and direct sequence spread spectrum, or DSSS.
Let's look at a compatibility list for 802.11. 802.11a is not compatible with most other
standards.
802.11b is compatible with 802.11g and n. 802.11g is compatible with 11b and
11n. 802.11n is compatible with 802.11b, g, and ac. 802.11ac is compatible with 802.11n.
Let's talk about the wireless standards. 802.11b uses the 2.4-gigahertz RF band and DSSS as
its form of modulation. It offers up to 11 megabits per second networking with a maximum
indoor range of 115 feet and a maximum outdoor range of 460 feet.
802.11a uses the 5-gigahertz RF band and OFDM as its method of modulation.
11a offers up
to 54 megabits per second networking with a maximum indoor range of 115 feet and a maximum
outdoor range of 390 feet. Then, there is 802.11g. It uses the 2.4-gigahertz
RF band and it can use both OFDM and DSSS as its methods of modulation. 11g offers up
to 54 megabits per second networking with a maximum indoor range of 125 feet and a maximum outdoor range of 460 feet. Then, we have 802.11n. It can use both the
2.4 and the 5-gigahertz radio frequency bands with OFDM as its method of modulation. 802.11n
can offer up to 600 megabits per second networking with a maximum indoor range of 230 feet and
a maximum outdoor range of 820 feet. Finally, we have 802.11ac. It uses the 5-gigahertz
radio frequency band with OFDM as its method of modulation. It's expected to offer up to
1 gigabit per second networking with a maximum indoor range of 115 feet.
At this point in
time, we do not have a maximum outdoor range as they're still working on establishing that.
That concludes this session on troubleshooting wireless networks part II. We talked about
some wireless environmental factors. Then, we concluded with a brief discussion on wireless
standard related factors. On behalf of PACE-IT, thank you for watching this session, and I hope to do another one soon..
