zl50416 Zarlink Semiconductor, zl50416 Datasheet - Page 22

• Manufacturer Part Number: zl50416
• Description: Managed 16-port 10/100 M + 2-port 1 G Ethernet Switch
• Manufacturer: Zarlink Semiconductor

5.3.3
Aging time is controlled by register 400h and 401h.
The aging module scans and ages MCT entries based on a programmable “age out” time interval. As we indicated
earlier, the search module updates the source MAC address and VLAN port association timestamps for each frame
it processes. When an entry is ready to be aged, the entry is removed from the table, and a “Delete MAC Address”
message is sent to inform the CPU.
Supported MAC entry types are: dynamic, static, source filter, destination filter, IP multicast, source and destination
filter, and secure MAC address. Only dynamic entries can be aged; all others are static. The MAC entry type is
stored in the “status” field of the MCT data structure.
5.3.4
The table below provides a mapping from VLAN ID to VLAN index. It is maintained by system software and is
checked by the hardware search engine for every incoming frame. This table has 4K entries and is stored in
external SRAM. It is organized as 512 × 8 entries (total of 4K VLAN indexes) as shown. Each VLAN index is 8 bits.
Each VIX represents the mapping result from the associated VLAN ID (VLANID = 0x004 is mapped to VIX4).
Unused VLAN ID’s have their corresponding VIX programmed to hexadecimal 00. Used VLAN ID’s have Their
corresponding VIX programmed to hexadecimal 01 through FF. In other words, 255 VLAN’s are supported. The VIX
value is a pointer to the entries in the VLAN Index port association table (internal memory).
The VLAN Index port association table is used by both software and hardware. It contains 256 entries. Each entry
has 17 fields, such that each field represents the port status of that particular VLAN.
E
N
T
R
I
E
S
VIX7
…
…
VIX4095
Port
Bit
0
1
:
:
255
Aging
VLAN Table
Not Used
63 to 50
VIX6
…
…
VIX4094
VIX5
…
…
VIX4093
Table 3 - VLAN Index Port Association Table
CPU
49 48
Table 2 - VLAN Index Mapping Table
Not
Use
47 32
VIX4
…
…
VIX4092
Zarlink Semiconductor Inc.
ZL50416
P15
31 30
22
VIX3
…
…
VIX4091
……
VIX2
…
…
VIX4090
P3
7 6
P2
5 4
VIX1
…
…
VIX4089
P1
3
2
VIX0
…
…
VIX4088
Data Sheet
P0
1
0