The Internet is composed of many interconnected networks and/or
subnets.
Networks and subnets are interconnected by routers.
In today's lecture we investigate the technology of networks --
that is, the technology used to physically connect a group of
computers. Most networks (sometimes called LANs)
have the following characteristics:
Usually employ some form of shared medium --
the networked systems all "see" one another's transmissions. This
is much less true than it once was, but the core technology is
designed around the assumption of a shared medium.
Data rates are high, usually at least 10Mbps (ie, 10 million
bits per second -- data is always transmitted "serially", or one
bit at a time), commonly 100Mbps, occasionally 1Gbps.
Privately owned; no involvement of public telcommunications
providers, usually limited geographical area such as campus,
business premises, etc.