Released
PMC-Sierra, Inc.
PM9311/2/3/5 ETT1™ CHIP SET
Data Sheet
PMC-2000164
ISSUE 3
ENHANCED TT1™ SWITCH FABRIC
The complete sequence of events at the input side is shown in Figure 15.
1. Linecard a issues a request to the EPP to send a cell to output channel (0,1). The initial request
count is zero, so the arrival of the request then increments the request count to one.
2. The LCS Grant Manager sees that there is at least one empty cell buffer in the virtual output queue
for output (0,1), and that the request counter for (0,1) is non-zero and so it decrements the request
counter (back to zero) and issues a grant to the linecard.
3. The linecard then forwards the actual cell body to the EPP which stores the cell in the virtual
output queue. The EPP also issues a request to the Scheduler, indicating that there is a cell
waiting to be transferred to output (0).
4. Later the Scheduler issues a grant to the EPP which can forward the cell through the Crossbar to
the output channel (the EPP at port 0).
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
39
PMC [ PMC-SIERRA, INC ]
