PM9313 datasheet(61/343 Pages) PMC

61 / 343 page

PM9311/2/3/5 ETT1™ CHIP SET

PMC-2000164

ISSUE 3

ENHANCED TT1™ SWITCH FABRIC

Released

Data Sheet

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

PMC-Sierra, Inc.

Figure 27. Ingress Port Logic

The egress side of the port also looks at the TDM table. If the Output Valid bit in the current entry is set,

then the port tells the Scheduler that it expects to receive a TDM cell at some fixed time in the future. This

prevents the Scheduler from trying to schedule a best-effort cell to that port at the same time.

If the Scheduler doesn’t receive the input TDM request bit from the specified input port, then it assumes

that there is no TDM cell ready to be transmitted, and thus any egress port that expected to receive that

cell will now become available for best-effort cell scheduling.

When the TDM cell enters the egress port, it is placed in a separate, 96-entry, egress queue dedicated for

TDM traffic. Whenever this queue is non-empty, the cell at the head of the queue is sent immediately to the

linecard (provided that the Output Scheduler is not frozen).

Current TDM Slot Time

OC-48c 0

OC-48c 1

OC-48c 2

OC-48c 3

“Send”Table

TDM Cell Queues

991

OC-48c Select

TDM Identifier

PM9313 Datasheet(PDF) 61 Page - PMC-Sierra, Inc