X.25 and packet switched services offer a common reference point to begin reviewing WAN communications technology. The X.25 protocol provides customer application access to a packet switched network.
Customer data is cut into packets, each containing an address and error check information.
The packets are transported, or dynamically routed, through the network to the designated final address where the packets are re-assembled into the original customer data. X.25 and packet switching are a very reliable, efficient and standards-based technology. The drawback in today's high-octane world is the error checking requirements inherent between network switch hops. This requirement tends to add transportation delay. Each packet switch checks each packet for problems before forwarding it onto the next switch.