User`s guide

Glossary
D-5
combination port filter
A filter which may include several configurable fields and may be
used to filter bridge traffic in a very specific manner.
concentrator
A device that provides attachment points for stations that are not
connected directly to an FDDI dual ring. The concentrator is
connected directly to the network; the stations connect to the
concentrator.
congestion
A condition where a portion of the network is overloaded with
more data than can be transmitted in the desired time period.
counter-rotating ring
Refers to two signal paths in a ring topology that send signals in
opposite directions.
CSMA/CD (carrier-sense multiple access with collision
detect)
A channel access (contention) method which requires each station
to wait for an idle channel before transmitting. In addition, stations
are able to detect overlapping transmissions (collisions) and
retransmit in the event of a data collision.
DAC (dual attachment concentrator)
A concentrator connected to both the primary and secondary rings
of an FDDI ring. A concentrator includes additional ports for the
connection of other FDDI stations or concentrators.