Here is a list of terms introduced in this module that may be new to you:
- Bridge: A device that connects two local area networks (LANs) or elements of the same LAN. The two LANs being connected can be alike or dissimilar. Unlike routers, bridges are protocol-independent.
They simply forward packets of data without analyzing and re-routing messages. Consequently, they are faster than routers, but also less versatile.
- Data packet: A piece of a message transmitted over a packet-switching network. One of the key features of a packet is that it contains the destination address in addition to the data. In IP networks, packets are often called datagrams.
- Extranet: A Web site for existing customers rather than the general public. It can provide access to paid research, current inventories and internal databases, virtually any information that is private and not published for everyone.
An extranet uses the public Internet as its transmission system, but requires passwords to gain access.
- Firewall: A method for keeping a network secure. It can be implemented in a single router that filters out unwanted packets, or it may use a combination of technologies in routers and hosts.
Firewalls are widely used to give users access to the Internet in a secure fashion as well as to separate a company's public Web server from its internal network. They are also used to keep internal network segments secure. For example, a research or accounting subnet might be vulnerable to snooping from within.
- Internet: A global network connecting millions of computers that are joined through a high-speed backbone of data links.
- Intranet: An in-house Web site that serves the employees of the enterprise. Although intranet pages may link to the Internet, an intranet is not a site accessed by the general public. Using programming languages such as Java, client/server applications can be built on intranets. Since Web browsers that support Java run under Windows, Mac and UNIX, such programs also provide cross-platform capability.
Intranets use the same communications protocols and hypertext links as the Web and thus provide a standard way of disseminating information internally and extending the application worldwide at the same time.
- IP or Internet Protocol: An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing.
- LAN: A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link to a server. Typically, a LAN encompasses computers and peripherals connected to a server within a distinct geographic area such as an office or a commercial establishment
- Multicasting: The sending of a message to a select group, as when a user sends an email to an electronic mailing list.
- Protocol: Network protocols are formal standards and policies comprised of rules, procedures and formats that define communication between two or more devices over a network. Network protocols govern the end-to-end processes of timely, secure and managed data or network communication.
- Router: A device that forwards data packets from one local area network (LAN) or wide area network (WAN) to another. Based on routing tables and protocols, routers read the network address in each transmitted frame and make a decision on how to send it based on the most expedient route (traffic load, line costs, speed, or bad lines). Routers work at layer 3 in the protocol stack, whereas bridges and switches work at the layer 2.
Most routers are specialized computers that are optimized for communications; however, router functions can also be implemented by adding routing software to a file server.
- Switch: A network switch (also called switching hub, bridging hub, officially MAC bridge) is a computer networking device that connects devices together on a computer network by using packet switching to receive, process, and forward data to the destination device.
- Switched LANs: LANs that use switches to join segments.
- TCP/IP: (Transmission Control Protocol/Internet Protocol)A communications protocol developed under contract from the U.S. Department of Defense to internetwork dissimilar systems. Invented by Vinton Cerf and Bob Kahn, this de facto UNIX standard is the protocol of the Internet and has become the global standard for communications. TCP provides transport functions, which ensures that the total amount of bytes sent is received correctly at the other end.
IP provides the routing mechanism. TCP/IP is a routable protocol, which means that all messages contain not only the address of the destination station, but also the address of a destination network.
This allows TCP/IP messages to be sent to multiple networks within an organization or around the world, hence its use in the Internet.
- Tunneling: A technology that enables one network to send its data via another network'S connections.
- VPN: A software-defined network offering the appearance, functionality, and usefulness of a dedicated private network.
- WAN (Wide area network): A communications network that covers a wide geographic area, such as state or country.
In the next module, you will learn about other core technologies that are part of an eBusiness solution.
