A protocol is a set of rules that governs the communications between computers on a network. These rules include guidelines that regulate the following characteristics of a network access method, allowed physical topologies, types of cabling, and speed of data transfer.
The most common protocols are:
Ethernet:
The Ethernet protocol is by far the most widely used Ethernet uses an access method, called CSMNCD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit, If some other node is already transmitting on the cable, the computer will wait and try again, when the line is clear. Sometimes, two computers attempt to transmit at the same instant. When this happens a collision occurs. Each computer then backs off and waits a random amount of time before attempting to re-transmit, With this access method, it IS normal to have collisions. However, the delay caused by collisions and re-transmitting Is very small and does not normally affect the speed of transmission on the network.
The Ethernet protocol allows for linear bus, star, or tree topologies. Data can be transmitted over twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps.
Token Ring:
The Token Ring protocol was developed by IBM in the mid-1980. The access method used involves token-passing. In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, 4 simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer. The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable. It can operate at transmission speeds of 4 Mbps or 16 Mbps
FDDI:
Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances. The access method used by FDDI involves token-passing FDDI uses a dual ring physical topology. Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring.
A reliable double-ring metropolitan area network architecture, DORFMAN is based on an enhanced Fiber Distributed Data Interface (FDD) protocol. DORFMAN is composed of two local ring networks interconnected via two monitors. The two monitors are used to perform simple routing and error recovery logic as well as mode transitions of DORFMAN.
ATM:
Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher. ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets. ATM supports a variety of media such as video, CD-quality audio, and imaging. ATM employs a star topology, which can work with fiber optic as well as twisted pair cable.
ATM has proved very successful in the WAN scenario and numerous telecommunication providers have implemented ATM in their wide-area network cores Also many ADSL (Asymmetric Digital Subscriber Line) implementations use ATM.. However, ATM has failed to gain wide use as a LAN technology, and its complexity has held back its full deployment as the single integrating network technology in the way that its inventors originally intended.
The most common protocols are:
- Ethernet
- Token Ring
- FDDI
- ATM
Ethernet:
The Ethernet protocol is by far the most widely used Ethernet uses an access method, called CSMNCD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit, If some other node is already transmitting on the cable, the computer will wait and try again, when the line is clear. Sometimes, two computers attempt to transmit at the same instant. When this happens a collision occurs. Each computer then backs off and waits a random amount of time before attempting to re-transmit, With this access method, it IS normal to have collisions. However, the delay caused by collisions and re-transmitting Is very small and does not normally affect the speed of transmission on the network.
The Ethernet protocol allows for linear bus, star, or tree topologies. Data can be transmitted over twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps.
Token Ring:
The Token Ring protocol was developed by IBM in the mid-1980. The access method used involves token-passing. In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, 4 simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer. The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable. It can operate at transmission speeds of 4 Mbps or 16 Mbps
FDDI:
Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances. The access method used by FDDI involves token-passing FDDI uses a dual ring physical topology. Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring.
A reliable double-ring metropolitan area network architecture, DORFMAN is based on an enhanced Fiber Distributed Data Interface (FDD) protocol. DORFMAN is composed of two local ring networks interconnected via two monitors. The two monitors are used to perform simple routing and error recovery logic as well as mode transitions of DORFMAN.
ATM:
Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher. ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets. ATM supports a variety of media such as video, CD-quality audio, and imaging. ATM employs a star topology, which can work with fiber optic as well as twisted pair cable.
ATM has proved very successful in the WAN scenario and numerous telecommunication providers have implemented ATM in their wide-area network cores Also many ADSL (Asymmetric Digital Subscriber Line) implementations use ATM.. However, ATM has failed to gain wide use as a LAN technology, and its complexity has held back its full deployment as the single integrating network technology in the way that its inventors originally intended.
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