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Q6-2 What Network Technology Supports the Cloud?

Laptop 1 Laptop 2 247
Phone 1

Phone 2

Wireless connections (dotted lines)
Computer 1 use IEEE 802.11

LAN devices acts as a router,
switch, and wireless access point
(AP)

Internet Internet Wired connections (solid lines) use
Service IEEE 802.3
Provider

Figure 6-5
Typical Small Office/Home Office
(SOHO) LAN Computer 2 Computer 3 Printer Fax

The IEEE 802.3 protocol is used for wired LAN connections. This protocol standard, also
called Ethernet, specifies hardware characteristics, such as which wire carries which signals.
It also describes how messages are to be packaged and processed for wired transmission over
the LAN.
Most personal computers today support what is called 10/100/1000 Ethernet. These prod-
ucts conform to the 802.3 specification and allow for transmission at a rate of 10, 100, or 1,000
Mbps (megabits per second). Switches detect the speed a given device can handle and communi-
cate with it at that speed. If you check computer listings at Dell, Lenovo, and other manufacturers,
you will see PCs advertised as having 10/100/1000 Ethernet. Today, speeds of up to 1 Gbps are
possible on wired LANs.
By the way, the abbreviations used for communications speeds differ from those used for
computer memory. For communications equipment, K stands for 1,000, not 1,024 as it does for
memory. Similarly, M stands for 1,000,000, not 1,024 * 1,024; G stands for 1,000,000,000,
not 1,024 * 1,024 * 1,024. Thus, 100 Mbps is 100,000,000 bits per second. Also, communica-
tions speeds are expressed in bits, whereas memory sizes are expressed in bytes. These are different
units of measurement. One byte consists of eight bits. This means a 1 MB file would consist of
8,388,608 bits. If you sent a 1 MB file over a 1 Mbps connection, it would take more than 8 sec-
onds to send because your connection speed is measured in bits per second, not bytes per second.
Wireless LAN connections use the IEEE 802.11 protocol. Several versions of 802.11 exist,
and as of 2015, the most current one is IEEE 802.11ac. The differences among these versions are
beyond the scope of this discussion. Just note that the current standard, 802.11ac, allows speeds
of up to 1.3 Gbps, though few users have an Internet connection fast enough to take full advan-
tage of that speed.
Bluetooth is another common wireless protocol used to make PAN connections. It is designed
for transmitting data over short distances, replacing cables. Devices, such as wireless mice,
keyboards, printers, and headphones, use Bluetooth to connect to desktop computers. Other