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Black Box Modular Switches Installation and User Guide (8/99)
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4.0 OPERATION
This chapter describes the functions and operation of the LE14XXA-Series.
4.1 Switching Functionality
A LE14XXA-Series provides switched connectivity at Ethernet wire-
speed among all
of its ports. The LE14XXA-Series supports10/100Mbs for copper media and 10 or 100Mb
separate traffic domain for fiber port to maximize bandwidth utilization and network
performance. All ports can communicate to all other ports in a LE14XXA-Series, but local
traffic on a port will not consume any of the bandwidth on any other port.
LE14XXA-Series units are plug-and-play
devices. There is no software configuring to
be done at installation or for maintenance. The only hardware configuration settings are user
options for UP-LINK on RJ-45 4-
port. Half / Full duplex mode and 10 or 100Mbps selection for
the switched ports can
be done through jumper settings inside the unit. The internal functions of
both are described below.
Filtering and Forwarding
Each time a packet arrives on one of the switched ports, the decision is taken to either
filter or to forward the packet. Packe
ts whose source and destination addresses are on the same
port segment will be filtered, constraining them to one port and relieving the rest of the network
from processing them. A packet whose destination address is on another port segment will be
forward
ed to the appropriate port, and will not be sent to the other ports where it is not needed.
Traffic needed for maintaining the operation of the network (such as occasional multi-cast
packets) are forwarded to all ports.
The LE14XXA-Series Switches operate in the store-and-forward switching mode,
which eliminates bad packets and enables peak performance to be achieved when there is heavy
traffic on the network.
Address Learning
All 16-port LE14XXA-Series units have address table capacity of 24K node addr
esses
(12K for 8-port models), suitable for use in large networks. They are self-learning, so that as