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Infrastructure Security: Devices and Media • Chapter 6 405

Table 6.3 Categories and Descriptions of UPT/STP Cables
Category Description

Category 7 Rated at 600 MHz; suitable for Ethernet, Fast Ethernet,
Gigabit Ethernet, Token Ring, and 155 Mbps ATM.

Category 7 Similar to Category 7 but is a proposed international
(Class F) standard to be included in ISO/IEC 11801.

This type of cable typically uses a RJ-11 connector (like a telephone) to con-
nect to devices on the network, but can also use a RJ-45 connector. CAT-5 cable
contains four pairs of wires and uses RJ-45 connectors for its connections.This
type of cabling is typically used for newer token ring networks and Ethernet net-
works. Compared to coax, it is easier to run this type of cable and it takes up less
space in the cable runs. In addition, it allows for centralized connectivity points
such as hubs and switches. It is important to make sure that the hubs and switches
are physically secure so that unauthorized connections cannot be made by simply
plugging in a new cable.
Due to the ability to use hubs and switches with UTP/STP cable, it is possible
to support bus topology, star topology, and token-ring topology. Bus topology is sup-
ported with hubs, but even the support of a bus topology in a network using
UTP/STP has an advantage over a coax bus network. If a network device is
removed or a cable breaks, the hub detects the break and routes the circuit around
it.This keeps the network up even if these problems occur.
Star topology looks the same as bus topology using a hub on a network dia-
gram, but differs in the way the hub routes the circuit internally.A diagram illus-
trating the star topology is shown in Figure 6.18. In a hub using a star topology,
data is communicated to all ports simultaneously rather than flowing from one to
the next.
In addition, some hubs and switches allow administrators to disable ports that
are not in use. Using this capability is also a very good idea.

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