Explain the architecture of TCP/IP protocol. - Application Layer, Transport and Internet Layer and Network Interface Layer. TCP/IP protocol maps four layers namely Application Layer, Transport and Internet Layer and Network Interface Layer.
Application Layer: Accessibility of other services accessibility by applications is provided by the application layer. Protocol definitions that are used by application for exchanging data is also done by application layer. HTTP, FTP, SMTP, Telnet are some of the application layer protocols for exchanging information. Domain Name System, Routing Information Protocol, Simple Network Management Protocols are used for facilitating the use and management of TCP/IP networks.
Transport Layer: Session and datagram communications services are provided by transport layer to the application layer. The protocols used for data transmission are TCP and UDP. TCP provides a reliable one-to-one communication service. Establishing TCP connection, sequencing and acknowledgement of sent packets are the responsibilities of TCP. UDP provides one-to-one, one-to-many, connectionless, unreliable communication services. UDP is recommended when the amount of data is small and fit into single packet.
The responsibilities of the OSI Transport layer and some of the responsibilities of OSI session layer are encompassed in the Transport layer.
Internet Layer The responsibility of addressing, packaging, and routing functions are held by the Internet Layer. The protocols for this layer are IP, ARP, ICMP, and IGMP.
IP addressing, routing and fragmentation and assembling of packets are the responsibilities of IP protocol.Resolution of the Internet layer address to the network interface layer is the responsibility of ARP. Providing diagnostic functions and reporting errors due to the unsuccessful delivery of IP packets is dealt by ICMP. The management of IP multicast groups is the responsibility of IGMP.
Network Interface Layer Placing TCP/IP packets on the medium of network and receiving TCP/IP packets off the network medium is the responsibility of Network Interface Layer. It was designed as independent of network access method, frame format, and medium. LAN technologies which use Ethernet and Token ring and WAN technologies such as x.25 are connected among them using Network Interface Layer.
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