Question: What is TCP/IP?

TCP/IP is very popular protocol suite, which is used in Ethernet home network, wireless network and Internet. TCP/IP stands for Transmission Control Protocol/Internet Protocol, named after these 2 popular protocols (TCP, IP). Of course there are many other protocols in this protocol suite.

The TCP/IP protocol suite contains 4 layers, and each layer works with specific functions and protocols.

Layer 4 Application Layer – This is the highest layer of TCP/IP protocol suite. This is the layer that closest to the end users, which it deals with applications that we use daily and also talks to the Transport layer. Those applications could be Web browser (HTTP, HTTPS) , email program (SMTP, ESMTP, POP3, IMAP) , telnet, SSH, BitTorrent and other networking applications.

Layer 3 Transport Layer - The Transport layer is mainly in charge of how to send the data to the destination after receiving the request from Application layer. TCP and UDP are 2 main protocols in this layer which can provide connection oriented or connectionless methods to transfer the data.

Layer 2 Internet Layer - IP (IPv4, IPv6) is the main protocol in Internet layer. This layer will read the source and destination IP address of packet, and then route to destination computer. Other protocols that belong to this layer are ARP, RIP, BGP, IPsec, ICMP, IGMP and RSVP.

Layer 1 Network Access Layer - Lowest layer of TCP/IP protocol suite and is the physical layer that do the actual data transmission using raw bits (0, 1). The popular implementations are different types of Ethernet or wireless network, PPP, DSL, xDSL and ISDN.