Black Box Dual-Speed Stackable Hubs Installation and User Guide
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2.2 Product Description - General
LH8000A Dual-Speed hubs have eight RJ-45 ports, each 10/100Mbps auto-sensing.
Each port can independently identify (via IEEE 802.3u auto-sensing) and accept either
100Mbps or 10Mbps Ethernet signals, adapting to match the best speed of the connected
device. There are two internal traffic domains in LH8000A hubs, one for the 100Mb traffic and
one for the 10Mbps traffic. The 100Mbps users share the 100Mb domain’s bandwidth and the
10Mbps users share the 10Mbps domain’s bandwidth.
Any LH8000A port can connect into either the 100 or the 10Mbps traffic domain,
and can also change from one traffic domain to the other at any time without affecting the
speed of other ports. The automatic per-port speed-sensing is continuous, allowing the
connected devices to change speed at any time without impairing the operation of the other
ports and connected devices.
Figure 2.2.1 : LH8000A-C is functionally both a 10Mb and a 100Mb hub in one
As LH8000A Dual-Speed units are stacked, the two shared traffic domains
automatically expand to support all of the ports in the stack. Any combination of 10Mbps and
100Mbps ports, up to the maximum of 32 ports (4 units) in one stack, can be in use at any time.
One LH8000A Model, the LH8000A-M, includes an internal bridge or switch module
which interconnects the 10Mbps and the 100Mbps traffic domains. This enables all users on an
LH8000A-M hub or an LH8000A stack, whether 100Mbps or 10Mbps , to talk to each other.
The internal switch of the LH8000A-M filters and selectively forwards packets between the
10Mbps and the 100Mbps domains, maintaining peak performance in each domain unaffected
by local traffic in the other domain. The internal bridge is self-learning, with large address table
capacity for up to 8K node addresses. As networked nodes are added or removed or move from
one speed domain to the other, the LH8000A’s internal switch automatically keeps track.
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COL
ACT
PWR
LK
RX
BR
UPLINK
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GARRETT
PWR
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Magnum
8000E
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Stackable
Hub
GARRETT
PWR
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10Mb Hub
100Mb Hub
LH8000A-C
