KSZ8842-16MBL-EVAL MICREL [Micrel Semiconductor], KSZ8842-16MBL-EVAL Datasheet - Page 75

• Manufacturer Part Number: KSZ8842-16MBL-EVAL
• Description: 2-Port Ethernet Switch with Non-PCI Interface
• Manufacturer: MICREL [Micrel Semiconductor]

Micrel, Inc.
Bit
7
6
5
4
3
2
1
0
October 2007
Default
1
1
1
1
0
0
0
1
R/W
RW
RW
RW
RW
RW
RW
RW
RW
Description
Unicast Port-VLAN Mismatch Discard
1 = no packets can cross the VLAN boundary.
0 = unicast packets (excluding unknown/multicast/broadcast) can cross the VLAN
boundary.
Multicast Storm Protection Disable
1 = “Broadcast Storm Protection” does not include multicast packets. Only DA =
FFFFFFFFFFFF packets are regulated.
0 = “Broadcast Storm Protection” includes DA = FFFFFFFFFFFF and DA[40] = 1
packets.
Back Pressure Mode
1 = carrier sense-based Back Pressure is selected.
0 = collision-based Back Pressure is selected.
Flow Control And Back Pressure Fair Mode
1 = fair mode is selected. In this mode, if a flow control port and a non-flow control port
talk to the same destination port, packets from the non-flow control port may be
dropped. This prevents the flow control port from being flow controlled for an extended
period of time.
0 = in this mode, if a flow control port and a non-flow control port talk to the same
destination port, the flow control port is flow controlled. This may not be “fair” to the
flow control port.
No Excessive Collision Drop
1 = the switch does not drop packets when 16 or more collisions occur.
0 = the switch drops packets when 16 or more collisions occur.
Huge Packet Support
1 = accepts packet sizes up to 1916 bytes (inclusive). This bit setting overrides setting
from bit 1 of the same register.
0 = the max packet size is determined by bit 1 of this register.
Legal Maximum Packet Size Check Enable
0 = accepts packet sizes up to 1536 bytes (inclusive).
1 = 1522 bytes for tagged packets, 1518 bytes for untagged packets. Any packets
larger than the specified value are dropped.
Priority Buffer Reserve
1 = each port is pre-allocated 48 buffers, used exclusively for high priority (q3, q2, and
q1) packets. Effective only when the multiple queue feature is turned on.
0 = each port is pre-allocated 48 buffers used for all priority packets (q3, q2,q1, and
q0).
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KSZ8842-16/32 MQL/MVL/MVLI/MBL
M9999-102207-1.9