KSZ8893-MQL Micrel Semiconductor, Inc., KSZ8893-MQL Datasheet - Page 87

• Manufacturer Part Number: KSZ8893-MQL
• Description: Integrated 3-Port 10/100 Managed Switch with PHYs
• Manufacturer: Micrel Semiconductor, Inc.

VLAN Table
The KSZ8893MQL uses the VLAN table to perform look ups. If 802.1Q VLAN mode is enabled (register 5, bit 7 =
1), this table will be used to retrieve the VLAN information that is associated with the ingress packet. This
information includes FID (filter ID), VID (VLAN ID), and VLAN membership as described in the following table.
If 802.1Q VLAN mode is enabled, KSZ8893MQL will assign a VID to every ingress packet. If the packet is
untagged or tagged with a null VID, the packet is assigned with the default port VID of the ingress port. If the
packet is tagged with non null VID, the VID in the tag will be used. The look up process will start from the VLAN
table look up. If the VID is not valid, the packet will be dropped and no address learning will take place. If the VID
is valid, the FID is retrieved. The FID+DA and FID+SA lookups are performed. The FID+DA look up determines
the forwarding ports. If FID+DA fails, the packet will be broadcast to all the members (excluding the ingress port)
of the VLAN. If FID+SA fails, the FID+SA will be learned.
Micrel
November 2005
2. Static Address Table Write (Write the 8
Bit
19
18-16
15-12
11-0
Examples:
1. VLAN Table Read (read the 3
Then,
Write to reg. 124 (0x7C), static table bits [57:56]
Write to reg. 125 (0x7D), static table bits [55:48]
Write to reg. 126 (0x7E), static table bits [47:40]
Write to reg. 127 (0x7F), static table bits [39:32]
Write to reg. 128 (0x80), static table bits [31:24]
Write to reg. 129 (0x81), static table bits [23:16]
Write to reg. 130 (0x82), static table bits [15:8]
Write to reg. 131 (0x83), static table bits [7:0]
Write to reg. 121 (0x79) with 0x00
Write to reg. 122 (0x7A) with 0x07
Write to reg. 121 (0x79) with 0x14
Write to reg. 122 (0x7A) with 0x02
Read reg. 129 (0x81), VLAN table bits [19:16]
Read reg. 130 (0x82), VLAN table bits [15:8]
Read reg. 131 (0x83), VLAN table bits [7:0]
Name
Valid
Membership
FID
VID
Table 17. Format of Static VLAN Table (16 Entries)
R/W
R/W
R/W
R/W
R/W
rd
Description
= 1, entry is valid
= 0, entry is invalid
Specify which ports are members of the VLAN. If
a DA lookup fails (no match in both static and
dynamic tables), the packet associated with this
VLAN will be forwarded to ports specified in this
field. For example, 101 means port 3 and 1 are in
this VLAN.
Filter ID. KSZ8893MQL supports 16 active
VLANs represented by these four bit fields. FID
is the mapped ID. If 802.1Q VLAN is enabled,
the look up will be based on FID+DA and
FID+SA.
IEEE 802.1Q 12 bits VLAN ID
entry)
th
Entry)
87
// Write static table selected
// Trigger the write operation
// Read VLAN table selected
// Trigger the read operation
Default
1
111
0x0
0x001
KSZ8893MQL/MQLI
M9999-111705