What is the purpose of a WAN? In this sample chapter from Connecting Networks v6 Companion Guide, explore how wide-area networks (WANs) operate, what services are available, the differences between private and public WAN technologies, and more.
Your medium-sized company is upgrading its network. To make the most of the equipment currently in use, you decide to purchase WAN modules instead of new equipment.
All branch offices use either Cisco 1900 or 2911 series ISRs. You will be updating these routers in several locations. Each branch has its own ISP requirements to consider.
To update the devices, focus on the following WAN module access types:
A business can use private lines or the public network infrastructure for WAN connections. A public infrastructure connection can be a cost-effective alternative to a private connection between LANs, as long as security is also planned.
WAN access standards operate at Layers 1 and 2 of the OSI model, and are defined and managed by the TIA/EIA, ISO, and IEEE. A WAN may be circuit-switched or packet-switched.
There is common terminology used to identify the physical components of WAN connections and who, the service provider or the customer, is responsible for which components.
Service provider networks are complex, and the service provider’s backbone networks consist primarily of high-bandwidth fiber-optic media. The device used for interconnection to a customer is specific to the WAN technology that is implemented.
Permanent, dedicated point-to-point connections are provided by using leased lines. Dialup access, although slow, is still viable for remote areas with limited WAN options. Other private connection options include ISDN, Frame Relay, ATM, Ethernet WAN, MPLS, and VSAT.
Public infrastructure connections include DSL, cable, wireless, and 3G/4G cellular. Security over public infrastructure connections can be provided by using remote-access or site-to-site VPNs.
