Cabletron Systems 9T425-16, 9T427-16, 9T428-16 TNIB

Operation

3-2

Figure 3-1. 9T425-16, 9T427-16, and 9T428-16 Block Diagram

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 9000 ASIC.

Network Interface Blocks (NIBs) check for valid data packets entering the system.

If an errored data packet is found, the SmartSwitch 9000 ASIC ßags the error and

does not forward the errored data packet to any outbound ports. Once in this

common format, the SmartSwitch 9000 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.

TNIB

The Token Ring Network Interface Block (TNIB) converts Token Ring data

packets received through front panel ports into a common canonical format that

allows the SmartSwitch 9000 ASIC Engine to determine the proper destination

port. The TNIB also converts data packets from the common canonical format

back to Token Ring packets for transmission out front panel ports.

i960

Processor

Smart

Switch

ASIC

TNIB

SMB 1

SMB 10

DC/DC

Convertor

Diagnostic

Controller

TNIB

INB

NIB