SMSC LAN9311 User Manual

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

Revision 1.4 (08-19-08)

72

SMSC LAN9311/LAN9311i

 

After each packet is received, the bucket is decremented. If the Committed Burst bucket has sufficient
tokens, it is debited and the packet is colored Green. If the Committed Burst bucket lacks sufficient
tokens for the packet, the Excess Burst bucket is checked. If the Excess Burst bucket has sufficient
tokens, it is debited, the packet is colored Yellow and is subjected to random discard. If the Excess
Burst bucket lacks sufficient tokens for the packet, the packet is colored Red and is discarded.

Note: All of the token buckets are initialized to the default value of 1536. If lower values are

programmed into the CBS and EBS parameters, the token buckets will need to be normally
depleted below these values before the values have any affect on limiting the maximum value
of the token buckets.

Refer to 

 through 

 for detailed register

descriptions.

Based on the flow monitoring mode, an ingress flow definition can include the ingress priority. This is
calculated similarly to the transmit queue with the exception that the Priority Regeneration and the
Traffic Class table are not used. As shown in 

, the priority can be based on:

„

The precedence bits in the IPv4 TOS octet

„

The DIFFSERV mapping table indexed by the IPv4 TOS octet or the IPv6 Traffic Class octet

„

The VLAN tag priority field (but not through the per port Priority Regeneration table)

„

The port default

0-3

80 nS

100 Mbps

4

100 nS

80 Mbps

5

120 nS

67 Mbps

6

140 nS

57 Mbps

7

160 nS

50 Mbps

9

200 nS

40 Mbps

12

260 nS

31 Mbps

19

400 nS

20 Mbps

39

800 nS

10 Mbps

79

1600 nS

5 Mbps

160

3220 nS

2.5 Mbps

402

8060 nS

1 Mbps

804

16100 nS

500 Kbps

1610

32220 nS

250 Kbps

4028

80580 nS

100 Kbps

8056

161140 nS

50 Kbps