IT

WAN Technology

Stands for Wide Area Network is similar to a Local Area Network (LAN), but it's a lot bigger. Unlike LANs, WANs are not limited to a single location. Many wide area networks span long distances via telephone lines, fiber-optic cables, or satellite links. They can also be composed of smaller LANs that are interconnected. The Internet could be described as the biggest WAN in the world.

Frame Relay –is A packet-switched technology of 64Kbps up to 45Mbps (T3).it provides features for dynamic bandwidth allocation and congestion control.

PPP - PPP can be used to create point-to-point links between different vendors’ equipment. 

PPP Facts

• It can be used on a wide variety of physical interfaces including asynchronous serial, synchronous serial (dial up), and ISDN.
• It supports multiple Network layer protocols, including IP, IPX, AppleTalk, and numerous others.
• Optional authentication is provided through PAP (2-way authentication) or CHAP (3-way authentication).
• It supports multilink connections, load-balancing traffic over multiple physical links.
• It includes Link Quality Monitoring (LQM) which can detect link errors and automatically terminate links with excessive errors.
• It includes looped link detection that can identify when messages sent from a router are looped back to that router. This is done through routers sending magic numbers in communications. If a router receives a packet with its own magic number, the link is looped.

PPP uses two main protocols to establish and maintain the link.

TCP/IP (7 OSI Layers)

Transmission Control Protocol/Internet Protocol, the suite of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the Internet, making it the de facto standard for transmitting data over networks. 

The OSI, or Open System Interconnection, model defines a networking framework to implement protocols in seven layers. Control is passed from one layer to the next, starting at the application layers in one station, and proceeding to the bottom layer, over the channel to the next station and back up the hierarchy.

DNS                                                                                                                            

Short for Domain Name System (or Service or Server), an Internet service that translate domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address.