Part-1 1. What does the transport layer do? The transport layer performs three functions: • Establishing end-end connections: linking the application layer to the network. • Addressing: finding the address of the ultimate destination computer. • Packetizing: breaking long messages into smaller packets for transmission. 2. What does the network layer do? The network layer performs two functions: • Routing: determining the next computer to which the message should be sent to reach the final destination • Addressing: finding the address of that next computer. 3. What are the parts of TCP/IP and what do they do? Who is the primary user of TCP/IP? As the name implies, TCP/IP has tow parts. TCP is the transport layer protocol that links the application layer to the network layer. It performs packetizing: breaking the data into smaller packets, numbering them, ensuring each packet is reliably delivered, and putting them in the proper order at the destination. IP is the network layer protocol and performs addressing and routing. IP software used at each of the intervening computers through which the message passes; it is IP that routes the message to the final destination. The TCP/IP was developed for the U .S. Department of Defense’s Advanced Research Project Agency network (ARPANET). TCP/IP is the
popular network layer protocol, used by almost 80 percent of all BNs, MANs. In 1998, TCP/IP moved past IPX/SPX as the most common protocol used on LANs. 6. Why is TCP/IP the most popular protocol? TCP/IP is the world’s popular network layer protocol, used by almost 80 percent of all BNs, MANs. In 1998, TCP/IP moved past IPX/SPX as the most common protocol used on LANs. TCP/IP allows reasonably efficient and error-free transmission. Because it performs error checking, it can send large files across sometimes-unreliable networks with great assurance that the data will arrive uncorrupted. TCP/IP is compatible with a variety of data link protocols, which is one reason for its popularity. 7. Compare and contrast the three types of addresses used in a network. Computers can have three different addresses: application layer address, network layer address, and data link layer address. Data link layer addresses are usually part of the hardware whereas network layer and application layer addresses are set by software. Internet registrars assign network layer and application layer addresses for the Internet. Addresses within one organization are usually with the same first 3 bytes. Subnet masks are used to indicate whether the first 2 or 3 bytes (or partial bytes) indicate the same subnet. Some networks assign network layer addresses in a configuration file on the client computer whereas others use dynamic addressing in which a DHCP server assigns when a computer first joins the network. 8. How is TCP different from UDP?
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