KSZ8765CLXCC View Datasheet(PDF) - Micrel
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KSZ8765CLXCC Datasheet PDF : 153 Pages
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Micrel, Inc.
KSZ8765CLX
VLAN Support
The KSZ8765CLX supports 128 active VLANs and 4096 possible VIDs specified in IEEE 802.1q. KSZ8765CLX provides
a 128-entry VLAN table, which correspond to 4096 possible VIDs and converts to FID (7 bits) for address look-up, with a
maximum of 128 active VLANs. If a non-tagged or null-VID-tagged packet is received, then the ingress port VID is used
for look-up when IEEE 802.1q is enabled by the global Register 5 Control 3 bit [7]. In the VLAN mode, the look-up process
starts from the VLAN table look-up to determine whether the VID is valid. If the VID is not valid, the packet will then be
dropped and its address will not be learned. If the VID is valid, FID is retrieved for further look-up by the static MAC table
or dynamic MAC table. FID+DA is used to determine the destination port. The following table describes the different
actions in different situations of DA and FID+DA in the static MAC table and dynamic MAC table after the VLAN table
finishes a look-up action. FID+SA is used for learning purposes. The following table also describes learning in the
dynamic MAC table when the VLAN table has completed a look-up in the static MAC table without a valid entry.
Table 15. FID+DA Look-Up in the VLAN Mode
DA Found in Static
MAC Table?
Use FID Flag? FID Match?
No
Don’t Care
Don’t Care
No
Don’t Care
Don’t Care
Yes
0
Don’t Care
Yes
1
No
Yes
1
No
Yes
1
Yes
DA+FID Found in
Dynamic MAC Table?
No
Yes
Don’t Care
No
Yes
Don’t Care
Action
Broadcast to the membership ports
defined in the VLAN table bits [11:7].
Send to the destination port defined in the
dynamic MAC table bits [58:56].
Send to the destination port(s) defined in
the static MAC table bits [52:48].
Broadcast to the membership ports
defined in the VLAN table bits [11:7].
Send to the destination port defined in the
dynamic MAC table bits [58:56].
Send to the destination port(s) defined in
the static MAC table bits [52:48].
Table 16. FID+SA Look-Up in the VLAN Mode
SA+FID Found in Dynamic
MAC Table?
Action
No
The SA+FID will be learned into the dynamic table.
Yes
Time stamp will be updated.
Advanced VLAN features are also supported in KSZ8765CLX, such as VLAN ingress filtering and discard non-PVID
defined in bits [6:5] of the Port Control 2 Register. These features can be controlled on a per port basis.
July 23, 2014
49
Revision 1.0
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