KSZ8893MBL Datasheet, PDF (47/116 Pages) Micrel Semiconductor – Integrated 3-Port 10/100 Managed Switch with PHYs

Micrel, Inc.
KSZ8893MQL/MBL
Port Mirroring Support
KSZ8893MQL/MBL supports “Port Mirroring” comprehensively as:
“receive only” mirror on a port
All the packets received on the port are mirrored on the sniffer port. For example, port 1 is programmed to
be “receive sniff” and port 3 is programmed to be the “sniffer port”. A packet received on port 1 is destined
to port 2 after the internal lookup. The KSZ8893MQL/MBL forwards the packet to both port 2 and port 3.
The KSZ8893MQL/MBL can optionally even forward “bad” received packets to the “sniffer port”.
“transmit only” mirror on a port
All the packets transmitted on the port are mirrored on the sniffer port. For example, port 1 is programmed to
be “transmit sniff” and port 3 is programmed to be the “sniffer port”. A packet received on port 2 is destined
to port 1 after the internal lookup. The KSZ8893MQL/MBL forwards the packet to both port 1 and port 3.
“receive and transmit” mirror on two ports
All the packets received on port A and transmitted on port B are mirrored on the sniffer port. To turn on
the “AND” feature, set register 5 bit [0] to ‘1’. For example, port 1 is programmed to be “receive sniff”, port
2 is programmed to be “transmit sniff”, and port 3 is programmed to be the “sniffer port”. A packet
received on port 1 is destined to port 2 after the internal lookup. The KSZ8893MQL/MBL forwards the
packet to both port 2 and port 3.
Multiple ports can be selected as “receive sniff” or “transmit sniff”. In addition, any port can be selected as the
“sniffer port”. All these per port features can be selected through registers 17, 33 and 49 for ports 1, 2 and 3,
respectively.
IEEE 802.1Q VLAN Support
The KSZ8893MQL/MBL supports 16 active VLANs out of the 4096 possible VLANs specified in the IEEE 802.1Q
specification. KSZ8893MQL/MBL provides a 16-entries VLAN Table, which converts the 12-bits VLAN ID (VID) to
the 4-bits Filter ID (FID) for address lookup. If a non-tagged or null-VID-tagged packet is received, the ingress port
default VID is used for lookup. In VLAN mode, the lookup process starts with VLAN Table lookup to determine
whether the VID is valid. If the VID is not valid, the packet is dropped and its address is not learned. If the VID is
valid, the FID is retrieved for further lookup. The FID + Destination Address (FID+DA) are used to determine the
destination port. The FID + Source Address (FID+SA) are used for address learning.
DA found in
Static MAC
Table?
No
No
Yes
Yes
Yes
Yes
Use FID flag? FID match?
Don’t care
Don’t care
DA+FID
found in
Dynamic
MAC Table?
No
Don’t care
Don’t care
Yes
0
Don’t care
Don’t care
1
No
No
1
No
Yes
1
Yes
Don’t care
Action
Broadcast to the membership ports
defined in the VLAN Table bits [18:16]
Send to the destination port defined in the
Dynamic MAC Address Table bits [53:52]
Send to the destination port(s) defined in
the Static MAC Address Table bits [50:48]
Broadcast to the membership ports
defined in the VLAN Table bits [18:16]
Send to the destination port defined in the
Dynamic MAC Address Table bits [53:52]
Send to the destination port(s) defined in
the Static MAC Address Table bits [50:48]
Table 13. FID+DA Lookup in VLAN Mode
February 2010
47
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