GarrettCom 500-Series - Manual (Page 17)

Magnum 500-Series Switching Hubs Installation and User Guide (08/98)
GARRETT
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Example 3 : Magnum 528
In another situation similar to Example 2 above, the network may need to be
linked to a Fast Ethernet backbone. This application is handled by the Magnum 528
using one 100Mb switched port for local high speed servers and users, while using the
other 100Mb switched port for a link upstream.
Using two Magnum 528s and linking a 100Mb switched port from each unit,
one can implement a Fast Ethernet switched connection which can run in full duplex
mode. The result is similar to “stacking” the two Magnum 528s to provide a net total 16
ports of switched 10Mb plus 2 ports of switched 100Mb.
When using a Magnum 528’s 100Mb switched port as a link, it is frequently
desirable to make the connection to the upstream device using fiber cable operating at
100Mb speed. In this situation, an external 100Mb Media Converter unit (such as a
Magnum 15E) is used to change from twisted pair cable to fiber cable.
Because commercially-available 100Mb Media Converters do not support
10/100 speed auto-negotiation, it is necessary in this situation to operate both ends of the
fiber link with ports that have fixed 100Mb-speed capability. In addition, since 100Mb
fiber cable has severe distance limitations at half-duplex, it is almost always necessary to
operate such a fiber link in the full-duplex mode. Many low-end switching hubs that
only have auto-negotiation on their 100Mb ports cannot support this application, but the
Magnum 528 . . . with fixed 100Mb speed as a default setting, and with manually-
selected half- or full-duplex mode per Fast Ethernet port . . . handles this readily.
Figure 2.4d: The Magnum 528 provides 100Mb ports for backbone connections.
10Base-T
100Mb Hub
1 2 3 4 5 6 7 8
R X U PLIN K
10Mb LINK A UTO PW R LINK R X
1 2 Internet
100Mb Servers
and Workstations
10Mb Workgroup
Router
1 2 3 4 5 6 7 8
Ma gnum 800 E Wor kgr oup Hub 100 Mb/s GARRET T L INK
RX L INK
RX PWR COL 1 2 3 5 6 7
G A RRE TT LIN K
LI N K
PW R M ag n u m 1 5 E
M ed ia C on v er te r
10 0 Mb /s
100Mb Fiber Link
100Mb Media
Converter