CertiGuide to A+ (A+ 4 Real)  9  Chapter 13: Basic Networking Terminology       9  Wide Area Networking (WAN)

Dedicated Lines 1 ATM

Packet/cell switching is a WAN in which network devices share a permanent virtual circuit (PVC), which is like a point-to-point link to transport packets from a source to a destination across a providers of transport network like Sprint, MCI or other phone company.

In result, there is a connection with the high speed compared on speed to dedicated lines. The main advantage is that one WAN connection can give access to a plenty of the removed points at the expense of use of various routes through a network.

Switched networks can carry variable-size frames (packets) (Frame Relay and X.25) or fixed-size cells (ATM).

The most common packet-switched network type is Frame Relay because it provides high speeds of transfer, large than with dedicated lines flexibility and smaller price. The given technology perfectly works at creation of multi-service networks, where it is necessary to use QoS (Quality of Service) - to differentiate the traffic on the data, voice, video by certain rules. It is necessary for the consumer to stipulate with service provider CIR (Committed Information Rate) - guaranteed speed of transfer. One more advantage is that provider can dynamically give throughput as required.

Dedicated Lines 1 ATM