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Black Box Modular Switches
Installation and User Guide (8/99)
14
Example 2 : 8
-port LE1408A
In another application, a Switch is needed to provide a Fast Ethernet backbone. The
backbone consists of four high
-speed LAN segments, each operating over 100MB full-duplex
fiber lines. In addition to interconnecting the fiber backbone segments in the network center, the
Switch needs to provide high
-speed switched support for two central servers, for a 100MB
connection to a router, and for a dual
-speed hub serving a local workgroup of over a dozen users,
printers, etc.
The LE1408A equipped with one Fiber and one RJ-45 4-port modules provides an
economical solution, configured with 8 switched ports (four 100Mbps fiber and four 10/100 RJ
-
45) in a rack
-mount box. No Media Converters are needed. The Fiber 4PM can be selected to
provide any 100Mbps fiber media connector type desired. 4PMs with multi
-mode or single-
mode fiber types are available.
This requirement for connecting local devices over twisted pair cabling is handled by
the LE1408A using a RJ
-45 4-Port Module. The 4PM provides a switched port for two local
high speed servers, another for the router, another for the users connecting into a 16
-port dual-
speed hub such as the LE1408A.
Since 100Mb fiber Ethernet has severe distance limitations at half-duplex, it is
necessary in high speed backbones to operate fiber links in the full
-duplex mode. Many low-end
switches that only have RJ
-45 N-way 10/100Mb ports would need to have a media converter on
eac
h fiber line. But most media converters do not support auto-negotiation and would not enable
the fiber backbone lines to operate full
-duplex. But the LE1408A . . . with built-in switched fiber
ports at 100Mb speed, with full
-duplex mode as a default setting on fiber ports, and with some
RJ
-45 N-way 10/100Mb ports as well. . . handles this application readily.
Figure 2.4b: The LE1408A provides a 100Mb fiber backbone facility.
100Mb Fiber Link
segment
Internet
Router
1 2 3 4 5 6 7 8 9 10 11
12 13 14 15 16
X
UPLINK
LK/RX
PORT
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
PWR
BR
COL 10
COL 100
Magnum DS8016 Stackable Hub
Magnum 800E
Workgroup Hub
100 Mb/s
GARRETT
LINK
RX
LINK
RX
PWR COL
1 2 3
4
5 6 7
8
100Mb Servers
Magnum QS5116
Fiber Switch
GARRETT
PWR
ACT
100/10
2
3
1
FDX/HDX
4
LK ACT
Modular Switch
Black0Box le1408a
100/10 FDX/HDX
LK