Local Area Network

A local area network (LAN) is a computer network covering a small geographic area, like a home, office, or group of buildings. The defining characteristics of LANs, in contrast to Wide Area Networks (WANs), include their much higher data transfer rates, smaller geographic range, and lack of a need for leased telecommunication lines.
Ethernet over unshielded twisted pair cabling, and Wi-Fi are the two most common technologies.

Structured cabling systems

  • UTP Category 5 and 5e, Fibre FDDI etc
  • Wireless

Mid-range / Mainframe connectivity

  • 3270, TCP/IP & LAT

Wide Area Network

Wide Area Network (WAN) is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries). Or, less formally, a network that uses routers and public communications . Contrast with personal area networks (PANs), local area networks (LANs), campus area networks (CANs), or metropolitan area networks (MANs) which are usually limited to a room, building, campus or specific metropolitan area (e.g., a city) respectively.

The largest and most well-known example of a WAN is the Internet . WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers provide connections from an organization’s LAN to the Internet. WANs are often built using leased lines. At each end of the leased line, a router connects to the LAN on one side and a hub within the WAN on the other. Leased lines can be very expensive. Instead of using leased lines, WANs can also be built using less costly circuit switching  or packet switching methods. Network protocols including TCP/IP  deliver transport and addressing functions. Protocols including Packet over SONET/SDH ,MPLS ,ATM, and Frame relay are often used by service providers to deliver the links that are used in WANs. X.25 was an important early WAN protocol, and is often considered to be the “grandfather” of Frame Relay as many of the underlying protocols and functions of X.25 are still in use today (with upgrades) by Frame Relay.

Virtual Private Network

A virtual private network (VPN) is a communications network tunneled through another network, and dedicated for a specific network. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

SSL (Secure Socket Layer) VPN Solutions from CBS:

  • Celestix