TCP/IP Protocol Suite

The TCP/IP protocol Suite includes many protocols, as shown in the Figure below. Each layer has its own working protocol. Application layer protocols include the Domain Name System(DNS), host configuration protocols such as Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP), Email protocols (POP, SMTP, and IMAP), file transfer protocols, and HyperText Transfer Protocol. The Transport Layer includes the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

The Internet layer working protocols are Internet Protocol (IP), Network Address Translation (NAT), Internet Control Messaging Protocol (ICMP), and routing protocol. The Network Access Layer includes Address Resolution Protocol (ARP), Point to Point Protocol (PPP), Ethernet, and Interface Drives.

The lower layer protocols in the network access layer are responsible for delivering the IP packet over the physical medium. Standards organizations, such as IEEE have developed these lower-layer protocols.

The Protocol suite is implemented; as a TCP/IP stack on both the sending and receiving hosts to provide end-to-end delivery of applications over a network. The Ethernet protocols are used to transmit the packet over the physical medium used by the LAN.

TCP/IP Communication Process

1. Host-1 sends data using the Hypertext Markup Language (HTML) page to Host-2.

2. The application protocol HTTP header was added to the front of the HTML data, as shown in the figure below. The header has various information, such as the IP header, Ethernet header, TCP header, and the HTTP version the server is using, as well as a status code representing it that has information for the web client.

The application layer protocol HTTP forwards the HTML-formatted web page data to the transport layer (Layer 4 of the OSI Model). The Transport Layer then adds a TCP header to the HTTP data and converts the data into a segment. In this example, the transport layer also handles each conversation between Host-1 and Host-2.

4. Next, the IP information is added to the front of the TCP information and converted to the packet segment. IP assigns the source and destination IP addresses.

5. The Ethernet protocol, known as a data link frame, adds information to both ends of the IP packet. This frame is delivered to the nearest router along the path towards the web client. This router removes the Ethernet information, analyzes the IP packet, determines the best path, inserts the packet into a new frame, and sends it to the next neighbouring router towards the destination. Each router removes and adds new data link information before forwarding the packet.

6. This data is transported through the internet through media and intermediary devices.

At the receiving end, the client receives the data link frames that contain the data. Each protocol header is processed and then removed in the opposite order it was added. After removing all headers, the user receives and sees the original data, as shown in the figure below.

[qsm quiz=9]