It
is anticipated that extremely dynamic traffic routing procedures
will be employed, implemented by programs in each IMP.
In particular a version of the Baran (of RAND) hot potato
method may he employed. The notion of the packet (an entity
of 1000 bits maximum) was introduced, where a given message
could be composed of many packets. The routing mechanism
would deal with the packet, thus packets of the same message
may traverse different routes from source to destination.
- Elmer
Shapiro; Computer
Network Meeting of Oct 9-10, 1967; Nov 1967. |
Switching systems enable packet networks
to dynamically optimize their operation and recover from localized
damage. The switching in Internet networks is performed
by computers called routers at
the intersection where networks come together. Internet routers
use a number of standard routing protocols to
switch the incoming packets from one network to another as required.
Since routing software can reconfigure instantly, packet switching
networks can adapt to downed links and maintain communications
by roundabout paths even under very adverse conditions. Since the
systems are operating at electronic speed, this means messages
can be sent through even large, damaged networks very quickly.
One of the biggest advantages of packet switched networks is that
they use the available bandwidth very efficiently by sharing it
at all times, so that no one communication ties up a communication
link. In the early 1970's, the cost of electronics came down to
the point where this model became cost-effective, and it became
possible to install routing equipment at each network node, enabling
wide area communications for the first time.
Today's Internet routing protocols use sophisticated algorithms
that have been optimized for efficiency over many years. In practice,
most
network connections today are very reliable, and so all packets
for a given computer are usually sent over the same path as long
as it remains operational.
Today, switches are getting faster and faster, with optical switches
providing large advances in speed, and the ultimate end result
is now within site: near zero switching time as a packet moves
from one network to another at near the speed of light.
