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: