SMSC LAN9311 Manual De Usuario

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface

SMSC LAN9311/LAN9311i

397

Revision 1.4 (08-19-08)

 

The ingress rate metering/color table consists of 24 Committed Information Rate (CIR) registers (one
per port/priority), a Committed Burst Size register, and an Excess Burst Size register. All metering/color
table registers are 16-bits in size and are accessed indirectly via the 

. Descriptions of these registers are detailed in

 below.

Excess Burst Size
This register specifies the maximum excess burst size in bytes. Bursts larger than 
this value that exceed the excess data rate are dropped.

Either this value or the Committed Burst Size should be set larger than or 
equal to the largest possible packet expected.

All of the Excess Burst token buckets are initialized to this default value. 
If a lower value is programmed into this register, the token buckets will 
need to be normally depleted below this value before this value has any 
affect on limiting the token bucket maximum values.

This register is 16-bits wide.

R/W

0600h

Committed Burst Size
This register specifies the maximum committed burst size in bytes. Bursts larger 
than this value that exceed the committed data rate are subjected to random 
dropping.

Either this value or the Excess Burst Size should be set larger than or 
equal to the largest possible packet expected.

All of the Committed Burst token buckets are initialized to this default 
value. If a lower value is programmed into this register, the token buckets 
will need to be normally depleted below this value before this value has 
any affect on limiting the token bucket maximum values.

This register is 16-bits wide.

R/W

0600h

Committed Information Rate (CIR)
These registers specify the committed data rate for the port/priority pair. The rate 
is specified in time per byte. The time is this value plus 1 times 20nS.

There are 24 of these registers each 16-bits wide.

R/W

0014h