High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface

Datasheet

14.5.4.11Buffer Manager Random Discard Table Write Data Register (BM_RNDM_DSCRD_TBL_WDATA)

Register #:

1C0Ah

Size:

32 bits

This register is used to write the Random Discard Weight table.

Note: The Random Discard Weight table is not initialized upon reset or power-up. If a random discard is enabled, the full table should be initialized by the host.

BITS

DESCRIPTION

TYPE

DEFAULT

 

 

 

 

31:10

RESERVED

RO

-

 

 

 

 

9:0

Drop Probability

R/W

000h

 

These bits specify the discard probability of a packet that has been colored

 

 

 

Yellow by the ingress metering. The probability is given in 1/1024’s. For

 

 

 

example, a setting of 1 is one in 1024, or approximately 0.1%. A setting of

 

 

 

all ones (1023) is 1023 in 1024, or approximately 99.9%.

 

 

 

There are a total of 16 probability entries. Each entry corresponds to a range

 

 

 

of the number of buffers used by the ingress port, as specified in Section

 

 

 

14.5.4.10, "Buffer Manager Random Discard Table Command Register

 

 

 

(BM_RNDM_DSCRD_TBL_CMD)".

 

 

 

 

 

 

SMSC LAN9312

421

Revision 1.4 (08-19-08)

 

DATASHEET