Computing devices that are connected to the network must access and share the network to transmit and receive data. These devices are often referred to as nodes of the network. They work together by adhering to a common set of rules and procedures known as a protoco that enable them to communicate with one another. The two major protocols are the Ethernet and Transmission Control Protocol/Internet Protocol.
Ethernet. A common LAN protocol is Ethernet. Most large corporations use 10-gigabit Ethernet, where the network provides data transmission speeds of 10 gigabits (10 billion bits) per second. However, 100-gigabit Ethernet is emerging.
Transmission Control Protocol/Internet Protocol. The Transmission Control Protocol Internet Protocol (TCP/IP) is the protocol of the Internet. TCP/IP uses a suite of protocols, the main ones being the Transmission Control Protocol (TCP) and the Internet Protocol (IP). The TCP performs three basic functions: (1) It manages the movement of packets between computers by establishing a connection between the computers, (2) it sequences the transfer of packets, and (3) it acknowledges the packets that have been transmitted. The Internet Protocol (IP) is responsible for disassembling, delivering, and reassembling the data during transmission.
Before data are transmitted over the Internet, they are divided into small, fi xed bundles called packets. The transmission technology that breaks up blocks of text into packets is called packet switching. Each packet carries the information that will help it reach its destination the sender’s IP address, the intended receiver’s IP address, the number of packets in the message, and the number of the particular packet within the message. Each packet travels independently across the network and can be routed through different paths in the network. When the packets reach their destination, they are reassembled into the original message. It is important to note that packet-switching networks are reliable and fault tolerant. For example, if a path in the network is very busy or is broken, packets can be dynamically (“on the fl y”) rerouted around that path. Also, if one or more packets does not get to the receiving computer, then only those packets need to be resent.
Why do organizations use packet switching? The main reason is to achieve reliable end-to-end message transmission over sometimes unreliable networks that may have transient (short-acting) or persistent (long-acting) faults. The packets use the TCP/IP protocol to carry their data. TCP/IP functions in four layers (see Figure 6.7). The application layer enables client application programs to access the other layers, and it defi nes the protocols that applications use to exchange data. One of these application protocols is the Hypertext Transfer Protocol (HTTP), which defi nes how messages are
Ethernet. A common LAN protocol is Ethernet. Most large corporations use 10-gigabit Ethernet, where the network provides data transmission speeds of 10 gigabits (10 billion bits) per second. However, 100-gigabit Ethernet is emerging.
Transmission Control Protocol/Internet Protocol. The Transmission Control Protocol Internet Protocol (TCP/IP) is the protocol of the Internet. TCP/IP uses a suite of protocols, the main ones being the Transmission Control Protocol (TCP) and the Internet Protocol (IP). The TCP performs three basic functions: (1) It manages the movement of packets between computers by establishing a connection between the computers, (2) it sequences the transfer of packets, and (3) it acknowledges the packets that have been transmitted. The Internet Protocol (IP) is responsible for disassembling, delivering, and reassembling the data during transmission.
Before data are transmitted over the Internet, they are divided into small, fi xed bundles called packets. The transmission technology that breaks up blocks of text into packets is called packet switching. Each packet carries the information that will help it reach its destination the sender’s IP address, the intended receiver’s IP address, the number of packets in the message, and the number of the particular packet within the message. Each packet travels independently across the network and can be routed through different paths in the network. When the packets reach their destination, they are reassembled into the original message. It is important to note that packet-switching networks are reliable and fault tolerant. For example, if a path in the network is very busy or is broken, packets can be dynamically (“on the fl y”) rerouted around that path. Also, if one or more packets does not get to the receiving computer, then only those packets need to be resent.
Why do organizations use packet switching? The main reason is to achieve reliable end-to-end message transmission over sometimes unreliable networks that may have transient (short-acting) or persistent (long-acting) faults. The packets use the TCP/IP protocol to carry their data. TCP/IP functions in four layers (see Figure 6.7). The application layer enables client application programs to access the other layers, and it defi nes the protocols that applications use to exchange data. One of these application protocols is the Hypertext Transfer Protocol (HTTP), which defi nes how messages are
formulated and how they are interpreted by their receivers. The transport layer provides the application layer with communication and packet services. This layer includes TCP and other protocols. The Internet layer is responsible for addressing, routing, and packaging data packets. The IP is one of the protocols in this layer. Finally, the network interface layer places packets on, and receives them from, the network medium, which can be any networking technology. Two computers using TCP/IP can communicate even if they use different hardware and software. Data sent from one computer to another proceed downward through all four layers, beginning with the sending computer’s application layer and going through its network interface layer. After the data reach the receiving computer, they travel up the layers.
TCP/IP enables users to send data across sometimes unreliable networks with the assurance that the data will arrive in uncorrupted form. TCP/IP is very popular with business organizations because of its reliability and the ease with which it can support intranets and related functions. Let’s look at an example of packet-switching across the Internet. Figure 6.8 illustrates a message being sent from New York City to Los Angeles over a packet-switching network. Note that the different colored packets travel by different routes to reach their destination in Los Angeles, where they are reassembled into the complete message.
TCP/IP enables users to send data across sometimes unreliable networks with the assurance that the data will arrive in uncorrupted form. TCP/IP is very popular with business organizations because of its reliability and the ease with which it can support intranets and related functions. Let’s look at an example of packet-switching across the Internet. Figure 6.8 illustrates a message being sent from New York City to Los Angeles over a packet-switching network. Note that the different colored packets travel by different routes to reach their destination in Los Angeles, where they are reassembled into the complete message.
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