Black Box Dual-Speed Stackable Hubs Installation and User Guide
11
Example 3 :
For additional expansion, an LH8000A-M can be expanded by stacking LH8000A-C
“add-on” units. The additional stacked ports are all auto-sensing dual-speed, and can be used at
either 10Mbps or 100Mbps on a per-port basis.
The stacking cables connect the LH8000A units and carry the signals for both the
100Mbps and the 10Mbps domains. In a stack, all 10Mbps ports are together in a 10Mbps
traffic domain while all 100Mbps ports are similarly together on a separate 100Mbps traffic
domain. When one LH8000A-M unit with a bridge inside is present in a stack, its bridge will
support all of the ports in the stack and enable network traffic to move between the two stacked
domains.
An LH8000A stack operates as one dual-speed repeater. A dual-speed repeater is
both a 10Mb hub and a 100Mb hub at the same time. This means that the 10Mbps traffic
domain obeys all of the rules of 10Mbps shared Ethernet networks (hop counts, cable types,
cable distances, etc.) and can be treated as one 10Mbps repeater accordingly. Separately, the
100Mbps traffic domain obeys all of the rules of 100Mbps Fast Ethernet shared networks (hop
counts, PDVs, cable types, cable distances, etc.) and can be treated as one 100Mb repeater.
Both traffic domains function within the same physical LH8000A hub or stack of hubs.
Figure 2.7.3 : Stack of
LH8000As operate as
one 10/100 dual-speed
repeater
When expanding an Ethernet or Fast Ethernet installation, the LH8000A Hubs are
ideally suited for connecting servers and stations that have (or may have in the future ! ) mixed
speeds. Each traffic domain or segment has its own local traffic with the LH8000A-M
performing bridge-isolation of one domain from the other, filtering and selectively forwarding
10Mbps and 100Mbps packets between the two domains. This keeps the traffic between the
domains to a minimum and provides peak performance on both domains.
Print Server
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Router
10 Mb Hub
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Users
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UPLINK
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Dual Speed Stackable Hub
(412) 746-5500
BLACK BOX
