L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 29

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

Specifications of L-ET4148-50C-DB

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Preliminary Data Sheet
April 2006
Agere Systems Inc.
Functional Description
Flow Identification
All receive packets are assigned to one flow or another. Packets received via one of the 10/100/1000 Mbits/s
Ethernet ports are assigned to one of eight flows per port. Packets received via one of the 10 Gbits/s ports are
assigned to one of eighty flows per port. Each flow is associated with a policer that may be configured to limit the
total bandwidth of the flows.
By default, IP packets utilize Layer 3 information to identify the flow to which the packet is assigned while non-IP
packets utilize Layer 2 information. However, each port may be placed in a mode where Layer 2 information is uti-
lized for flow classification for all packets; including IP packets.
If Layer 2 information is being utilized and the receive packet is VLAN tagged, then the CoS field from the VLAN
tag is used to set the packet’s priority. Otherwise, the receive port’s default priority is used.
The result of the ACL processing for the receive packet has the ability to override any priority information that may
be embedded in the packet or implied by its receive port.
Finally, the combination of the source, destination, and priority information is used to identify a single flow.
USE IP ADDRESSES FOR
SOURCE/DESTINATION
USE IP DSCP FIELD
FOR PRIORITY
IP PACKET?
OVERRIDE?
LAYER 2
START
Y
N
N
Y
Single-Chip 48 x 1 Gbit/s + 2 x 10 Gbits/s Layer 2+ Ethernet Switch
(continued)
Figure 10. Flow Identification Process
COMBINE SOURCE, DESTINATION
AND PRIORITY TO FORM FLOW ID
Agere Systems - Proprietary
USE MAC ADDRESSES FOR
SOURCE/DESTINATION
USE 802.1p CoS FIELD
ACL OVERRIDE?
VLAN TAGGED?
FOR PRIORITY
DONE
Y
N
N
Y
VALUE FOR PRIORITY
USE DEFAULT PORT
USE ACL-DERIVED
PRIORITY
ET4148-50
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