ARPANET
During the late 1960s, a branch of the U.S. government titled the Advanced Research Projects Agency (ARPA) created one of the country's first wide area packet-switched networks.

Internet Protocol (IP)
Provides a connectionless data transfer service over heterogeneous networks by passing and routing IP datagrams.
IP datagram
Another name for a data packet
IP multicasting
The capability of a network server to transmit a data stream to more than one host at a time.
Subnet Masking
Take the host ID portion of an IP address and further divide it into a subnetID and a host ID.
TransmissionControl Protocol (TCP)
To turn an unreliable network (such as the one created by IP) into a reliable network that is free from lost and duplicate packets.

Thus, TCP essentially fills in some holes created by IP.

Socket
A precise identification of a particular applicationon a particular device.
Internet Control Message Protocol (ICMP)
Is used by routers and nodes, performs this error reporting for the Internet Protocol. All ICMP messages contain at least three fields: a type, a code, and the first eight bytes of the IP datagram that caused the ICMP message to be generated.
User Datagram Protocol(UDP)
A no-frills transport protocol that does not establish connections, doesnot attempt to keep data packets in sequence, and does not watch for datagrams that have existed for too long. Its header contains only four fields—Source Port, Destination Port, Length, and Checksum—and it is used by a small number of network services, such as DNS that do not need to establish a connection before sending data.

Address Resolution Protocol (ARP)
Takes an IP address in an IP datagram and translates it into the appropriate medium access control layer address for delivery on a local area network.
Dynamic Host Configuration Protocol (DHCP)
The most popular protocol that handles dynamic assignment. When a workstation running the DHCP client software needs to connect to the Internet, the protocol issues an IP request, which prompts the DHCP server to look in a static table of IP addresses.
Network Address Translation(NAT)
Lets a router represent an entire local area network to the Internet as a single IP address. When a user workstation on a company local area network sends a packet out to the Internet, NAT replaces the IP address of the user workstation with a corporate global IP address.

Virtual Private Network (VPN)
A data network connection that makes use of the public telecommunicationsinfrastructure but maintains privacy through the use of atunneling protocol and security procedures.
Tunneling Protocol
Such as the Point-to-Point Tunneling Protocol (PPTP), is the command set that allows an organization to create secure connections using public resources such as the Internet.
Point-to-Point Protocol (PPP)
Which is used for communication between two computers using aserial connection. The most common example of a serial connection is a DSL or cable modem connection between a user's workstation and an Internet serviceprovider.
IPSec
An abbreviation for IP Security, is a set of protocolsdeveloped by the Internet Engineering Task Force to support the secureexchange of data packets at the IP layer.

World Wide Web (WWW)
A vast collection of electronic documents that are located on many different Web servers, and contain text and images that can be accessed by simply clicking links within a browser's Web page.
Hypertext Markup Language (HTML)
Can be generated manually with a text-based editor such as Notepad, or through the use of a Web page authoring tool.
Hypertext Transfer Protocol (HTTP)
An application layer protocol.
Uniform Resource Locator (URL)
Uniquely identifies files, Web pages, images, or any other types of electronic documents that reside on the Internet.
Domain Name System (DNS)
Which is a large, distributed database of Internet addresses and domain names. This distributeddatabase consists of a network of local DNS servers, mid-level DNS servers, and higher-level DNS servers.

Multipurpose Internet Mail Extensions (MIME)
Send an attachment such as database, spreadsheet, etc.
Simple Mail Transfer Protocol (SMTP)
An Internetprotocol for sending and receiving e-mail, and is used to perform the transfer.
Post Office Protocol version 3 (POP3)
The software that allows the user to save e-mail messages in a servermailbox and download them when desired from the server. POP3 is useful if you do not have a permanent connection to a network and must dial in using a temporary Internet connection.

Internet Message Access Protocol (IMAP)
A client/server protocolin which e-mail is received and held for you at your Internet server.
Telnet
A terminal emulation program for TCP/IP networks, such as the Internet, that allows users to log in to a remote computer.
Voice over IP (VoIP)
The practice of making telephone calls over the Internet.
Private VoIP
Because these systems do not use the Internet but instead remain internal, packet delays are minimal, and this makes VoIP attractive.
Session Initiation Protocol (SIP)
Introduced in 1998 by the Internet Engineering Task Force specifically for supporting the transfer of voice over the Internet. SIP is essentially an application layer protocol that can create, modify, and terminate voice sessions between two or more parties.

ENUM
A protocol that converts telephone numbers to fully qualified domain name addresses.
Listserv
Popular software program used to create and manage Internetmailing lists.
Real-Time Protocol (RTP)/ Real-Time Streaming Protocol (RTSP)
Two common application layer protocols that servers and the Internet use todeliver streaming audio and video data to a user's browser.
Instant messaging (IM)
Allows a user to see if people are currently logged in to the network and, if they are, to send them short messages in real time.

Electronic data interchange (EDI)
An electronic commercial transaction between two or more companies.
Micro-marketing
The gathering and use of the browsing habits of potential and current customers, which is important data for many companies.
Cookie
Data created by a Web server that is stored on the hard drive of a user's workstation. This data, called state information, provides a way for the Web site that stored the cookie to track a user's Web browsing patterns and preferences.
Intranet
A TCP/IP network inside a company that allows employees toaccess the company's information resources through an Internet-like interface. Using a Web browser on a workstation, an employee can perform browsing operations, but the applications that can be accessed through the browser areavailable only to employees within the company.

Extranet
When an intranet is extended outside the corporate walls to include suppliers, customers, or other external agents. Because anextranet allows external agents to have access to corporate computing resources, a much higher level of security is usually established.
The Internet Society (ISOC)
A volunteer organization that decides the future direction of the Internet.
The Internet Architecture Board (IAB)
A group of invited volunteers thatapproves standards.
The Internet Engineering Task Force (IETF)
A volunteer group that discusses operational and technical problems
The Internet Research Task Force (IRTF)
The group that coordinatesresearch activities.
Internet2
The government created a very-high-speed network that will cover the United States, interconnecting universities and research centers at transmission rates up to a gigabit per second (1000 Mbps).