Cabletron Systems SmartSwitch 9000, Руководство пользователя

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3-1
Chapter 3
Operation
The 9H423-26 module is a twenty-seven port device. Two front panel RJ21
connectors support twenty-four 100BASE-T ports, along with two SC fiber
connectors that support two 100BASE-FL ports. Each of these twenty-six ports is a
separate collision domain, while the 27th port connects to INB-B.
As shown in Figure 3-1, Fast Ethernet Network Interface Blocks (FENIBs) convert
data packets received from any of the 100BASE ports into a canonical frame
format before forwarding to the SmartSwitch ASIC, while the Internal Network
Bus Network Interface Block (INB NIB) converts data packets received from the
INB into a canonical format before forwarding to the SmartSwitch ASIC.
All data packets destined for a front panel port, the INB, or the i960 are converted
into the canonical format before forwarding to the SmartSwitch ASIC. Network
Interface Blocks (NIBs) check for valid data packets entering the system. If an
errored data packet is found, the SmartSwitch ASIC flags the error and does not
forward the errored data packet to any outbound ports. Once in this common
format, the SmartSwitch ASIC decides from header information the port
destination of data packets. Data packets are then converted from the canonical
format to the proper format for the interface destination whether it is a front panel
port, or connection to the INB.