Black Box Mixed-Media Fiber Hubs
Installation and User Guide (4/99)
16
Figure 2.7b LH8050A’s stacked. Cables connect “Out” and “In”
2.8
Bridge Module between the 10 Mbps and 100Mbps Domains
LH8050A’s contain a factory-installed bridge module to interconnect the two traffic
domains, filtering and selectively forwarding packets to allow only necessary packets to cross
between the domains. This enables all of the users and nodes connected into either domain,
whether 100Mbps or 10 Mbps , to communicate to each other, and it keeps local traffic on one
domain from consuming any of the bandwidth of the other domain.
The bridge operates in the store-and-forward mode, which filters out bad packets and
maintains optimum performance in both domains. Packet forwarding delay is only 5
μ
s (plus
packet time), much less than traditional store-and-forward bridge products, enabling the
LH8050As to maintain high network performance. The bridge has 8K node address capacity,
suitable for use in large networks. Addresses are self-learning so that filtering / forwarding of
10 Mbps and of 100Mbps packets is maintained correctly even when users move their
connection, or change speed, or power down.
Figure 2.8 : Internal
view of LH8050A with
bridge module installed
The LH8050A’s bridge module is implemented as a daughter board. LH8050A units have an
LED on the front labeled
BR
that will be
ON
when the bridge module is installed internally.
(The Model special LH8050A-C is an “client” unit for stacking, and has no bridge inside, so
it’s
BR
LED will always be off). In a stack of LH8050A’s and / or other compatible hubs, only
one unit with a bridge inside may be operating in any one stack
2.9
Features and Benefits
IN
ON
OFF
BONUS PORT
IN
IN
ON
OFF
BONUS PORT
ON
OFF
BONUS PORT
OUT
IN
OUT
IN
OUT
IN
FAN
EXHAUST
Bridge Module
