ES-CUTP and ES-FUTP Manual
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sequence occurs in a small fraction of a second and is transparent to an observer. See Section 4.6 for
additional details.
Another feature implemented in the ES switches is a collision-based flow-control mechanism
(when operating at half-duplex only). When the switch detects that its free buffer queue space is low,
the switch prevents more frames from entering by forcing a collision signal on all receiving half-duplex
ports in order to stop incoming traffic.
The latency (the time the frame spends in the switch before it is sent along or forwarded to its
destination) of the ES switches varies with the port-speed types, and the length of the frame is a variable
in this case as it is with all store-and-forward switches. For 10Mbps-to-10Mbps or 10Mbps-to-100Mbps
or 100Mbps-to-10Mbps forwarding, the latency is 15 microseconds plus the packet time at 10Mbps. For
100Mbps-to-100Mbps forwarding, the latency is 5 microseconds plus the packet time at 100Mbps.
2.6
Applications
The ES family of switches is designed to bring future-proof fiber connectivity and widely- used
copper connectivity to small user groups in offices, classrooms and labs.
Example 1. ES-FUTP-8
In this example, an ES-FUTP-8 switch serves a small classroom with multi-servers and mixed-
speed requirements like surfing the Internet or downloading data from servers or other sources. Some
users operate at 100Mbps, and some users and utility devices (such as print servers) run at 10Mbps.
High performance users need a high bandwidth backbone for access to a central LAN and central file
servers. The ES-FUTP-8 serves this requirement economically. The eight full-and half duplex-switched
port capability makes the required setup simple. Any attached node can change speed at any time
without affecting network operation or impacting other users.
Figure 2.6.1: The ES-FUTP-8 connects combinations of 10Mbps and100Mbps network devices and provides
a Fast Ethernet fiber backbone for access to the central LAN.
10Mbps hubs or switches can easily be cascaded into any port of the ES-FUTP-8, allowing a
simple plug-and-play addition of 100Mbps ports to an existing 10Mbps network. Nodes that are capable
of 100Mbps speed can be moved to an ES-FUTP port, and will automatically operate at the higher
speed.
The 100Mbps fiber port on the ES-FUTP can be used for accommodating high performance
data transfers, and provides fiber connectivity built-in rather than needing an auxiliary media converter
unit. The 100Mbps traffic does not use the bandwidth of the 10 Mbps domain, so overall performance of
the network is sustained at the highest possible level.
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