The communications technology of the public Internet, local area networks (LANs) and most wide area networks (WANs). The Internet Protocol (IP) is part of the TCP/IP protocol suite, and the terms "IP network" and "TCP/IP network" are synonymous.
Packet Switching
The Internet uses a packet-switched architecture, in which data are broken up into smaller "packets," with each packet containing a source address and destination address. Internet protocol (IP) packets are handed over to a data link layer protocol, for the physical transmission to the next node in the network path.
IP is the Network Layer
While "IP" refers to the entire TCP/IP protocol suite, "IP layer" refers to just the network-to-network part, occupying layer 3 in the "protocol stack" (see below). To learn about IP networking, see
TCP/IP and
TCP/IP abc's. See
OSI model,
IP address and
IP on Everything.
The TCP/IP "Stack"
IP layer 3 resides in the middle of the TCP/IP stack. It accepts packets from the upper layer TCP or UDP protocols and hands them to a lower layer data link protocol. Within a local network, the data link protocol is typically Ethernet. Within the public Internet, the data link protocols are SONET, ATM, frame relay and Carrier Ethernet.
The Protocols
Following are the primary standards that keep the Internet running:
Protocol Purpose
TCP/IP Network packet transmission
TCP Reliable delivery
UDP Unreliable delivery
IP Network to network
HTTP Web transmission
HTTPS Secure Web transmission
HTML Web page formatting
SMTP Email
FTP File transfer
DNS Domain name management
SNMP Network management
Telnet Remote execution
OSPF Routing protocol
RIP Routing protocol
ICMP Control messages
DHCP Assign IP addresses
ARP Find MAC addresses
RTP Real-time transmission
RTSP Real-time transmission + QoS