L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 158

• Manufacturer Part Number: L-ET4148-50C-DB
• Manufacturer: LSI

Specifications of L-ET4148-50C-DB

• Lead Free Status / RoHS Status: Supplier Unconfirmed

ET4148-50
Single-Chip 48 x 1 Gbit/s + 2 x 10 Gbits/s Layer 2+ Ethernet Switch
Appendix A: Registers
Packet_Buffer_Descriptor_Congestion_Threshold
Description: Global descriptor congestion thresholds.
Table 202. Packet_Buffer_Descriptor_Congestion_Threshold Register Parameters
Table 203. Packet_Buffer_Descriptor_Congestion_Threshold Field Parameters
Packet descriptors are managed in four groups. The global thresholds defined by this register apply to all four
groups. If any one of the four groups exceed an allocation threshold, then the threshold is considered crossed by
all four groups.
158
Base Address
Register Size
Register Instances
Register Spacing
Record Size
Record Instances
Record Spacing
mac_descriptor_congestion_threshold[13:4]
policer_descriptor_congestion_threshold[13:4]
0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
0
1
mac_descriptor_congestion_threshold[13:4]
2
Parameter
Figure 151. Packet_Buffer_Descriptor_Congestion_Threshold Register Diagram
3
4
Field Name
5
6
7
8
(continued)
9
10
11
Agere Systems - Proprietary
12
0
13
0
Instances = 1
Instances = 1
Offset = 0.18
Mode = R/W
Mode = R/W
Parameters
Offset = 0.2
14
0
15
0
0x000c_bc5c
16
Value
17
NA
NA
4
1
4
1
When the number of descriptors allocated equals or
exceeds this value, the packet buffer is considered
congested. The number of descriptors allocated
must drop below
congestion_threshold[13:4] minus
global_congestion_hysteresis[9:4] for the
state to change from congested to not congested.
The results of this congestion test are provided to
the Ethernet MACs.
Note: For proper operation, the maximum value for
When the number of descriptors allocated equals or
exceeds this value, the packet buffer is considered
congested. The number of descriptors allocated
must drop below
congestion_threshold[13:4] minus
global_congestion_hysteresis[9:4] for the
state to change from congested to not congested.
The results of this congestion test are provided to
the policers within the packet_processor mod-
ules.
Note: For proper operation, the maximum value for
policer_descriptor_congestion_threshold[13:4]
18
19
this field should be 0x1E0 or less.
this field should be 0x1E0 or less.
20
21
22
9
23
8
Description
24
7
Preliminary Data Sheet
25
6
26
5
Agere Systems Inc.
27
4
28
3
0
April 2006
29
2
0
30
1
0
31
0
0