What does TCP/IP mean?
TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a type of communication protocols used to interconnect networking devices over the internet. It was developed by the Department of Defense (DoD) project agency.
Transmission control protocol (TCP) and Internet Protocol ( IP) are two separate computer network protocols that define a set of rules to govern communications among all devices connected to the internet. TCP transport is frequently used to transfer data across the IP network.
Thus, the two protocols are used together so often that they are commonly referred to as TCP/IP. TCP/IP is actually a whole suite of protocols which includes TCP, IP, UDP, ARP, DNS, HTTP and ICMP.
TCP/IP specifies how information is exchanged over the network by giving end-to-end communications which identify how it ought to be broken up into packets, addressed, transmitted, routed and received in the destination. The TCP/IP reference model covers most of the popular protocols used in network communication. Due to its simplicity, it is still being widely adopted instead of the OSI model.
Comparing TCP/IP suite with OSI Layers
Much like the OSI network model, TCP/IP also includes a network model. TCP/IP was about the route of development as soon as the OSI standard was published and there was interaction among the designers of OSI and TCP/IP model. The TCP/IP version isn’t the same as the OSI version.
The OSI Model is only a reference/logical version. It was designed to explain the functions of the communicating system by isolating the communicating process into simpler and smaller parts. But when we discuss the TCP/IP version, it had been created and developed by the Department of Defense (DoD) in the 1960s and is based on standard protocols. It stands for Transmission Control Protocol/Internet Protocol. The TCP/IP Version is a brief version of the OSI model. It comprises four layers, unlike seven layers in the OSI model. The layers are:
- Process/Application Layer
- Host-to-Host/Transport Layer
- Internet Layer
- Network Access/Link Layer
The diagrammatic comparison of the TCP/IP and OSI model is given below:
1.Network Interface Layer
The network interface layer or the network access layer is responsible for transferring TCP/IP packets on and off the network medium. TCP/IP, which can transfer data irrespective of the network access method, frame format, or medium, can be used to communicate among different network types. It can work with LAN technologies such as Ethernet, token ring, FDDI, etc. and WAN technologies like frame relay etc. this also allow it to be compatible with new technologies such as Asynchronous Transfer Mode (ATM).
On most TCP/IP networks, none of the core IP protocols run on this layer as that is not necessary. However, the Serial Line Internet Protocol (SLIP) and the Point-To-Point Protocol (PPP) are used to facilitate communication with the physical layer.
The network interface layer corresponds with the data link and physical layers of the OSI model.
2. Internet Layer
The internet layer is responsible for accepting routing and diverting data packages. The core protocol of the internet layer includes internet protocol (IP), Internet control message Protocol (ICMP), Address Resolution Protocol (ARP) and Internet Group Management Protocol (IGMP).
This layer of the TCP/IP reference model is the equivalent of the network layer of the OSI model.
The transport layer delivers “end-to-end” communication to confirm that packets arrive in sequence and without error. It does so by acknowledging the reception of data and retransmitting lost packets.
This layer uses the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) as its core Protocols.
- TCP enables applications to reliably communicate with each other “one-to-one”. Data transmitted over TCP contains a header which helps in establishing an end-to-end connection between sending and receiving machines in order to confirm data transfer.
- UDP provides Datagram delivery service without the option to verify the connection between sending and receiving machines. As such, it is used for small amount of data transfer. It is faster when compared to TCP, but less reliable.
This layer of the TCP/IP reference model is directly comparable to the transport layer of the OSI model, but also includes some functions of the session layer.
This layer makes the services of the other layers available to the application that everyone can use
This layer also defines the protocol that application use for data transfer. While many new application layer protocols are being developed continuously, some of the protocols are currently in use are:
- Hypertext Transfer Protocol (HTTP) is used to transfer files from websites
- File Transfer Protocol (FTP) is used for interactive files transfer.
- Simple Mail Transfer Protocol (SMTP) is used for the transfer of email message mad attachment.
- Telnet means a terminal emulation protocol. It will be used for login on remotely to the network hosts.
- The Domain Name System (DNS) is used to resolve a hostname to an IP address.
- RIP stands for Routing Information Protocol, It is a routing protocol that routers used to exchange routing information on an IP internetwork.
The Application layer of the TCP/IP reference model corresponds with the Application layer of the OSI model.