L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 284

• 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 B: Configuration
Access Control Lists
Permit/Deny. All receive packets are associated with one ACL or another. This association is based on either the
packet’s receive port or its VLAN index. If the associated ACL is empty (i.e., no ACEs), then an automatic permit is
implied. If a receive packet fails to match all ACEs in a nonempty ACL, then an automatic deny is implied. Finally,
the first matching ACE’s acl_permit bit is used to either permit or deny the packet’s access to the ET4148-50
device.
If the acl_permit bit is set, the packet is received and processed normally. If this bit is deasserted, then the
matching packet is denied access. This does not necessarily imply that the packet is discarded. It may still be for-
warded to certain destinations such as the supervisor or a mirroring port. The effect of an ACL denial is specified
by Packet_Buffer_Acl_Deny_Mask.
ACL Logging. ACL logging refers to the copying of certain packets to the supervisor that match an ACE whose
acl_log bit is asserted. In general, logging only occurs when explicitly configured to do so, i.e., when an ACE is
encountered with acl_log asserted. The automatic logging of packets denied by default (matched no ACEs) may
also be enabled by setting auto_deny_log_en in the Acl_Mode register. The logging port or queue is identified
by the value set in Packet_Buffer_Acl_Log_Port.
Priority Replacement. One of the functions available via access control lists is the ability to override the priority
value of a receive packet based on a matching ACE. Every ACE result includes an acl_priority_code[4:0]
field. If bit 4 of this field is asserted, bits 3:0 are used to overwrite the priority value that had previously been
assigned to the receive packet during ingress parsing.
284
(continued)
INDEX
INDEX
INDEX
INDEX
INDEX
(continued)
Figure 296. ACE Map Reduction
Agere Systems - Proprietary
TABLE
TABLE
TABLE
TABLE
TABLE
MAP
MAP
MAP
MAP
MAP
ACE
ACE
ACE
ACE
ACE
(LAST ACE)
63
PRIORITY ENCODER
ACE MAP
ACE MAP
ACE MAP
ACE MAP
ACE MAP
(FIRST ACE)
0
Preliminary Data Sheet
RESULT
Agere Systems Inc.
April 2006