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Magnum 8000X Mixed-Media Fiber Hubs Installation and User Guide (05/ 02)
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for factory configuration at time of order. It is also possible for the rear bonus port to be
re-configured in the field by a trained technician to add or exchange a Switching Port
Module. Figure 2.5a below shows the internals of the Magnum 8000X with an SPM
installed in the Bonus Port, accessible from the rear.
Figure 2.5a: Inside view of Magnum 8000X with SPM installed. (Rear view)
For the specifications of available Switch Port Modules (SPMs), see Section
1.3. The functions of an SPM are described below.
1. Filtering and Forwarding / Address Learning
The SPM has two ports - one where media attaches, and one connecting into
the inside of the mixed-media fiber hub in which the SPM is mounted. For each packet
received by either port of the SPM, a decision is made to either filter the packet or to
forward the packet to the other port. Error packets are always filtered. For good packets,
the filter or forward decision is made based on the destination address contained in each
packet. If the destination address is on the segment from which the packet originated,
then it is filtered and not forwarded to the other segment. If the destination address
didn’t find a match in the address table, then is it forwarded to the other segment. If it is
a new address which the SPM didn’t previously didn’t know about, it “learns” the new
address and puts it in the port’s address table. The address tables have a capacity of 1K
addresses for each port.
MAIN BOARD
SPM
MODULE
POWER
SUPPLY
F
A
N
STACKING
CONNECTORS