Datasheet

KSZ8795CLX
DS00002112B-page 44  2016-2017 Microchip Technology Inc.
Matching Field
• MD [1:0]: MODE
There are three modes of operation defined in ACL. Mode 0 disables the current rule list, Mode 1 is qualification
rules for Layer 2 MAC header filtering, Mode 2 is used for Layer 3 IP address filtering and Mode 3 performs Layer
4 TCP port number/protocol filtering. While mode 0 is selected, there will be no action taken.
• ENB [1:0]: ENABLE
Enables different rules in the current list.
- When MD = 01
While ENB = 00, the 11 bits of the aggregated bit field from PM, P, RPE, RP, MM in the action field specify a
count value for packets matching the MAC address and TYPE in the matching fields.
The count unit is defined in MSB of FORWARD bit field; while = 0, µs will be used and while = 1, ms will apply.
The 2nd MSB of the FORWARD bit determines the algorithm used to generate an interrupt when the counter
terminates. When = 0, an 11-bit counter will be loaded with the count value from the ACL list and starts count-
ing down every unit of time. An interrupt will be generated when it expires, i.e., the next qualified packet has
not been received within the period specified by the value.
When = 1, the counter is incremented on every matched packet received and an interrupt is generated while
terminal count reach the count value in the ACL list, the count resets thereafter.
When ENB = 01, the MAC address bit field is participating in test; when ENB = 10, the MAC TYPE bit field is
used for test; when ENB = 11, both the MAC address and type are tested against these bit fields in the list.
- When MD = 10
FIGURE 3-11: ACL FORMAT