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

The Department of Defense Networking Model 81
Hardware involved in the network at the network interface level are as follows:
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Network medium, which can be coaxial, fiber optic or twisted-pair cabling,
or wireless networking
NIC, which has both a physical MAC address and a logical IP address.
MEDIA ACCESS CONTROL
MAC refers to the method used to allocate use of the medium among the computers
and devices on the network. In networking, access control is important since
many devices share a common medium, such as a coaxial cable or twisted-pair
cable.
Access control method lays out rules defining how access is allocated and is
performed by MAC layer protocols. The most common access control methods
today are:
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Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
Token passing
NETWORK INTERFACE HARDWARE/SOFTWARE
The network interface is established through the NIC, which employs both hardware
and software in connecting the device to the network media. Each type of
NIC uses a different type of connector to connect to the physical medium. The
connector types are delineated in the IEEE 802 specifications. The three most
prominent are Ethernet, which is defined in 802.3, Token Ring, defined in 802.5,
and wireless networking defined in 802.11.
The TCP/IP network interface layer defines protocols used by the NIC to receive,
assemble, address, and transmit. The Ethernet NIC is also responsible for
receiving/sending and assembling/disassembling data to and from the network
connection. The network interface layer in the DoD model encompasses the
functions of the OSI model’s physical and data link control layers and controls
media access and the assembly/disassembly of data at the lowest level of the
hierarchy.
EXAM WARNING
For the Network+ exam, it’s imperative that you understand the Institute of Electrical
and Electronics Engineers, Inc. (IEEE) 802 model and its specific standards. Focus on
the newer ones affecting today’s current technologies, such as Ethernet, wireless, and
security. Most significantly, Ethernet is defined in 802.3, Token Ring in 802.5, and wireless
networking in 802.11.
The standards vary depending on the network technology, but because TCP/IP works
independently of network technology, it can be used with networks such as Ethernet, Token
Ring, Asynchronous Transfer Mode (ATM), and Frame Relay interchangeably.