Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

Network Devices 45
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It is used to terminate the end of a leased T-carrier line, which is a high-speed
line that can be used to connect a LAN to a wide area network (WAN).
It can be a separate component that attaches to a router and provides an
interface.
Newer routers have more modular capabilities that allow you to purchase
what are sometimes referred to as WAN interface cards (WICs) that
incorporate the CSU/DSU into the actual port and cable connection.
Network Interface Cards
NICs, also referred to simply as network cards, provide an interface to the network
that allows data to be transmitted and received across the network media. Simply
put, the NIC performs the following functions:
■ It translates data from the parallel data bus to a serial bit stream for
transmission across the network.
■ It formats packets of data in accordance with protocol.
■ It transmits and receives data based on the hardware address of the card.
An NIC works as an interface between a computer’s expansion bus and the
medium that’s used to transmit and receive data across the network.
INSTALLING AN NIC
Installing an NIC is like installing any other interface card in a computer. You
have to determine the slot it will go in and have the right tools to remove the
expansion slot cover and to remove and insert screws. Newer computers do not
require any tools, not even screwdrivers.
NIC TYPES AND OPERATION
There are many different types of media and connectors that may be used on
a network, which is why there are different NICs and each NIC has its own
corresponding software drivers. Because of this, NICs are often defined by the
following criteria:
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The type of Data Link protocol they support, such as an Ethernet or Token
Ring
The type of media they connect to
The data bus for which they were designed
The NICs that exist in the various workstations on a network communicate with
each other using their own unique addresses. The MAC address, or hardware
address, is a 12-digit number consisting of digits 0 to 9 and letters A to F. It is
a hexadecimal (base16) number assigned to the card by the manufacturer. The
MAC address consists of two pieces: the first signifies which vendor it comes from
and the second is the serial number unique to that manufacturer. This address
must be unique on each network card on a network.