Released
PMC-Sierra, Inc.
PM9311/2/3/5 ETT1™ CHIP SET
Data Sheet
PMC-2000164
ISSUE 3
ENHANCED TT1™ SWITCH FABRIC
2. Turn off the EPP Output Scheduler for cells coming from itself. This will ensure that the cell will
stay in the virtual input queue in the egress buffers of the Dataslice.
3. Bring up all AIB links and enable non-tdm traffic in the Scheduler for this port. Enable the EPP and
take it out of LCS-2 Stop mode.
4. Write to the Outstanding Scheduler Request Counter in the EPP for this VOQ.
This will cause a request to be made to the Scheduler which will immediately issue a grant to the
EPP. The cell will be forwarded through the crossbar and back to the test port. The cell will then be
stored in the egress queue but will not be forwarded to the linecard because the Output Scheduler
was disabled in step 2.
5. The CPU can read the cell that is waiting in the egress queue and check that it passed through
OK.
6. Repeat as needed.
A number of variations can be done on this basic theme:
•
Because the Output Scheduler in each EPP can be stopped on a per source port basis, then in
step 1 the CPU can create a cell going to any egress port, not just to itself. This is possible even if
the egress port is currently online with real traffic. Thus it is possible to verify the datapath from the
new port to all other ports without interfering with existing flows.
•
•
Do not turn off the Output Scheduler in step 2 (or unfreeze it after Step 6). The linecard can then
verify that the cell is OK, thus testing more of the system.
Send enough cells so that the egress queue fills up and backpressures the input. So after sending
64 cells (OC-192 configuration) the egress queue should be full and thus prevent any more cells
being sent to this queue.
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PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
PMC [ PMC-SIERRA, INC ]
