Released
Datasheet
PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATM Traffic Management Device
Channel_B
Service Class (SC)
Current Channel
Previous
Channel_E
Channel_C
Channel_D
Figure 32. Receive Channel Ring after Channel_B is Served But It is Not Run-Limited
Channel_B
Service Class (SC)
Channel_A
Current Channel
Previous
Channel_C
Channel_E
Channel_D
Figure 33. Receive Channel Ring After Channel_A Gets Cell Through Fabric and is Added to Ring
2.5.4 Receive Congestion Management
The receive queue controller maintains current, congested, and maximum queue depth counts of
cells on a per-VC, per-SC, and per-device basis. Three congestion management algorithms are
available for use on a per-channel basis. In each channel’s RX_CH_CONFIG word (refer to
section 9.3.1.1 “RX_CH_CONFIG” starting on page 184) there are bits that enable EPD, CLP-
based discard, and EFCI. These may be used in combination. In addition, PTD is supported as a
mode of the EPD operation.
Per Service
Per Channel
Class (SC)
•
Per Device (DIR)
Figure 34. Receive Congestion Limits
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PMC [ PMC-SIERRA, INC ]
