In
general, a hub is the central part of a wheel where the
spokes come together. The term is familiar to frequent fliers
who travel through airport "hubs" to make connecting
flights from one point to another. In data communications,
a hub is a place of convergence where data arrives from
one or more directions and is forwarded out in one or more
other directions. A hub usually includes a switch of some
kind. (And a product that is called a "switch"
could usually be considered a hub as well.) The distinction
seems to be that the hub is the place where data comes together
and the switch is what determines how and where data is
forwarded from the place where data comes together. Regarded
in its switching aspects, a hub can also include a router.
1)
In describing network topologies, a hub topology consists
of a backbone (main circuit) to which a number of outgoing
lines can be attached ("dropped"), each providing
one or more connection port for device to attach to. For
Internet users not connected to a local area network, this
is the general topology used by your access provider. Other
common network topologies are the bus network and the ring
network. (Either of these could possibly feed into a hub
network, using a bridge.)
2)
As a network product, a hub may include a group of modem
cards for dial-in users, a gateway card for connections
to a local area network (for example, an Ethernet or a Token
Ring), and a connection to a line (the main line in this
example).
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