MDS213 Datasheet, PDF (56/120 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps + 1Gbps Ethernet Switch

MDS213
Data Sheet
Bit [26]VVLAN is Valid
Bit [27]CCPU is a member of this VLAN
Bit [31:28]1st byte: VLAN Index [3:0], 2nd byte: VLAN Index [7:4]
Note: P0 to P12 are used to identify the ports on the first chip, while P16 to P28 are used to identify the ports on the
second chip.
14.2.4.2 VLAN MAC Table
The size of this table is defined by VLMS subfield in BIT[8:7] of VTBP register. The base address of this table is
specified by VMACB subfield in BIT[15:9] of VTBP register. The VLAN MAC Table contains all associated VLANs
for each MAC Address learned by MDS213, and is used by the software to keep track of every MAC and its
associated VLANs. The contents of this table are set up by the Search Engine at the reception of incoming frames,
if the Search Engine is not fully occupied. When the Search Engine is too busy handling frame forwarding
decisions, microcode in the HISC engine will be assigned the setup new MAC to VLAN associations. Rows in this
table can be cleared up by microcode through a CPU software command during VLAN deletion or port link down. A
row in this table will be cleared and a new bit set up by the MDS213's microcode, when the port change of a MAC
address is detected.
There is a total of 2K entries in this table, one entry per MAC. Each entry may consist of 256, 128 or 64 bits, one bit
per VLAN. The total size of the VLAN Table may be 64, 32 or 16KB. This table must be located at the boundary of
its own table size.
MAC
handle
0 1 2 3 ......................... 100
256
0
1
2
3
.
.
.
.
.
.
.
..
.
.
2K
VLAN
ID
Figure 22 - VLAN MAC Table
This table can be accessed by CPU software through CPUIRCMD and CPUIRDAT registers.
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