1.1 Remote Access
1.1.4 Packet-switched connections
Packet switching is a WAN-switching method in which network devices share a single point-to-point link to transport packets from a source to a destination across a carrier network. Packet-switched networks use virtual circuits (VCs) that provide end-to-end connectivity, as shown in the Figure. Physical connections are accomplished through statistically programmed switching devices. Packet headers generally identify the destination.

Packet-switched networks can be either privately or publicly managed. The underlying switching fabric is transparent to the user, and the switches are responsible only for the internal delivery of data.

Packet-switched networks offer an administrator less control than a point-to-point connection. The bandwidth is shared, and the cost is generally less than a leased line. With WAN speeds comparable to those of leased lines, packet-switched networks are generally suitable links between two large sites that require high link utilization.

Like dedicated lines, packet-switched networks are also typically employed over synchronous serial connections. Some common connection standards that are supported on most routers include:

  • EIA/TIA-232
  • EIA/TIA-449
  • V.35
  • X.21
  • EIA-530

As a general rule, packet-switched connections are most cost-effective when the following situations occur.

  • Either long connect times or large geographic distances