Released
PMC-Sierra, Inc.
PM9311/2/3/5 ETT1™ CHIP SET
Data Sheet
PMC-2000164
ISSUE 3
ENHANCED TT1™ SWITCH FABRIC
Figure 15. (Continued)
EPP
OC-48c a Virtual Output Queues
0,0
2
0.0
0,1
0,2
0,3
Crossbar
OC-48c
linecard
0,1
Request (0)
Scheduler
0
0,2
3
0.3
7
Linecard a receives the grant and forwards cell body to go to output (0,1).
A request is made to the Scheduler.
EPP
OC-48c a Virtual Output Queues
0,0
2
0,0
0,1
0,2
0,3
Crossbar
OC-48c
linecard
0,1
1
0,2
3
Grant (0
Scheduler
0.3
7
The Scheduler issues a grant to queue (0,1).
The EPP then sends the cell through the crossbar to the output queue of port 0
.
The departure of a cell from the VOQ will mean that there is now space for at least one more cell in that
VOQ, and that could trigger the LCS Grant Manager to issue a new grant, assuming that a new request
had come in for that queue.
1.3.3.2 The Output Process
Each EPP consists of an input (i)EPP and an output (o)EPP. The request counters and virtual output
queues described above all reside in the iEPP. The oEPP has virtual input queues that receive the cells
forwarded via the Crossbar.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
41
PMC [ PMC-SIERRA, INC ]
