T-carrier
technology uses time division multiplexing (TDM) to divide a single channel into multiple channels for carrying voice, data, video, or other signals
SONET can
provide data transfer rates from 64 Kbps to 39.8 Gbps using the same TDM technique employed by T-carriers
When installing or
upgrading a WAN, consider its ability to integrate with your present LAN or WAN equipment, transmission speed required, security needed, geographical distance the WAN must span, growth, and cost
VPNs represent one
way to construct a WAN from existing
public transmission systems