The TCP/IP protocol set was developed by the OSI model. Therefore, the layers in the TCP/IP protocol group do not exactly match those in the OSI model. The original TCP/IP protocol set is defined as having four layers: host to network, Internet, transport, and application. However, when comparing TCP / IP with OSI, we can say that the host layer to the network is equivalent to the mixture of layers of physical layers and correlation data.
The Internet layer is equivalent to the network layer, and the application layer almost makes the session, the rendering layers, and the application layers with the TCP / IP transport layer taking into account part of the session layer duties. Therefore, in this article, assume that TCP / IP
The set of protocols consists of five layers: physical standards, network interfaces, Internet connectivity, and transport functions that correspond to the first four layers of the OSI model. However, the top three layers in the OSI model are represented in TCP / IP by a single layer called the application layer. TCP / IP is a hierarchical protocol consisting of interactive modules, each providing a specific function; however, the modules are not necessarily interconnected.
While the OSI model belongs to each of its layers, TCP / IP layer layers contain relatively independent protocols that can be mixed and matched to system requirements.
A hierarchical term means that each top-level protocol is supported by one or more lower-level protocols. In the transport layer, TCP / IP specifies three protocols: Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Transport Flow Control Protocol (SCTP). In the network layer, the main protocol specified by TCP / IP is the IP protocol; there are also some other protocols that support data traffic in this layer.
Physical and Data Link Layers.
In the physical layers and data link layer, TCP / IP does not specify any specific protocol. It supports all protocol standard and proprietary. The network in the TCP / IP work over the Internet can be a local or wide area network.
At the network layer (or, more accurately, the interwork layer), TCP/IP supports the Interworking Protocol. IP, in turn, uses four supporting protocols: ARP, RARP, ICMP, and IGMP. Each of these protocols is described in greater detail in a later chapter.
Internetworking Protocol (IP):
An interoperability protocol (IP) is the transmission mechanism used by the TCP / IP protocol. It is an unreliable and unreachable protocol – the best effort delivery service. The best effort term means that IP does not provide error checking or tracing. IP assumes unreliability of the core layers and does its best to get a transfer to its destination, but without any warranties. IP transfers data in packets called datagrams, and each is transferred separately.
Data datagrams can be transmitted across different routes and can reach out of sequence or be repeated. IP does not track paths and does not have an attachment to record datagrams once they arrive at their destination.
The limited functionality of the Internet Protocol should not be considered a weak point. IP provides abstract bone transfer functions that free the user from adding only those facilities for a given application, thus allowing for maximum efficiency.
Address Resolution Protocol.
The Address Resolution Protocol (ARP) is used to associate a logical address with an actual address. On a typical physical network, such as a LAN, each device is assigned a link by physical address or station address, and is usually printed on the network interface card (NIC). ARP is used to find the physical address of a node when its Internet address is known.
Reverse Address Resolution Protocol.
The RARP allows the host to discover its Internet address when it only knows its actual address. It is used when a computer is first connected to a network or when a computer is running without a disk.
Internet Control Message Protocol.
The Internet Control Message Protocol (ICMP) is a mechanism used by the host and portals to send a notification to the sender of the datagram problem. ICMP sends query messages and error messages.
Internet Group Message Protocol.
The Internet Group Message Protocol (IGMP) is used to facilitate the simultaneous transmission of a message to a group of recipients.
Traditionally, the transport layer was represented in TCP / IP by two protocols: TCP and UDP. IP is a protocol host, which means that a packet can be delivered from one physical device to another. UDP and TCP are the transport-level protocol responsible for delivering a message from a process (running the program) to another process. The new transport layer protocol, SCTP, is designed to meet the needs of some newer applications.
User Datagram Protocol.
User Datagram Protocol (UDP) is the simplest standard TCP / IP transport protocol. It is a process processing protocol that only adds port addresses, checksum error control, and length information to the top layer.
Transmission Control Protocol.
The Transmission Control Protocol (TCP) provides full transport layer services for the application. TCP is the trusted transport protocol. In this context, the term stream means communication: a connection must be established between the two ends of the transmission before either of them can transmit the data.
At the end of the transmission for each send operation, TCP divides a stream of data into smaller units called parts. Each section contains a serial number to rearrange after receiving, with a confirmation number for the sectors received. The sectors are implemented online within IP data schemas. At the receiving end, TCP collects each data map because it eventually comes to retransmission based on sequence numbers.
Stream Control Transmission Protocol.
The Stream Control Transfer Protocol (SCTP) provides a more recent application such as voice over the Internet. It is a transport layer protocol that combines the best UDP and TCP features.
The application layer in TCP / IP is equivalent to the integrated display and application layers combined in the OSI model. Many of the protocol are defined in this layer.