Chapter 3
Operation
The 9E312-12 module is a thirteen port device; twelve front panel ports, each represents a separate Ethernet collision domain and one port connected to INB1.
As shown in Figure 3-1, Ethernet Network Interface Blocks (ENIBs) convert data packets received from any front panel port into a canonical frame format before forwarding to the Fast Packet Switch (FPS), 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 (FPS). All data packets destined for a front panel port, the INB, or i960 are converted into the canonical format before forwarding to the FPS. Network Interface Blocks (NIBS) check for valid data packets entering the system. If an errored data packet is found, the FPS flags the error and does not forward the errored data packet to any outbound ports. Once in this common format, the FPS 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.
12 Front Panel Ports
| | | | | SMB 1 |
| i960 | | Diagnostic | SMB 10 |
| | Controller | |
| Processor | |
ENIB | | | |
| | | | |
| | | | DC/DC | |
| | | | Convertor | |
| | Fast | | INB | 1 |
| | Packet | NIB |
| | I |
ENIB | | Switch | | |
| | | N |
| | | |
| | | | |
| | | | | B |
| | | | | 2 |
ENIB | | | | | |
Figure 3-1. Packet Flow
3-1
