Vlan; Address Table Access; Address Security - ADMtek ADM5120 Datasheet

ADM5120
It will determine the packet priority. First it will check if the packet type meets VLAN or
TCP/IP. Then, it will check whether the value of VLAN tag or TCP/IP TOS/DS field
meets the registers setting. Depending on these two conditions, the scheme of weighted
round robin can determine the high and low priority of frames, and thus set the
transmitting order.
ADM5120 provides a function to improve the delay-time sensitive traffic in the flow-
control condition. When the port receives a priority frame, the backpressure & 802.3x
flow control can be turned off until no priority frame occurs within 1 or 2 seconds, then
turned back on again (Patent Pending). So it can prevent the jitter caused by the flow
control and the better timing-variation result for the priority traffic. This is a register
programmable function.
All the packets from the CPU port will be treated as high priority for the switch ports, and
then it can provide the best effort result for the CPU traffic (mostly they are this
bandwidth is charged.)

3.3.10 VLAN

ADM5120 supports 7 port-grouping VLAN. Each of thr VLAN will be treated as the
isolated ports.
ADM5120 provides the VLAN MAC address function, if the packet is assigned with the
VLAN address as its destination MAC address, then this packet will be forwarded to the
CPU via DMA.
For example, port0 is the WAN port, and the others are the LAN port, then WAN port set
as VLAN1 and others set as VLAN2. And program the different MAC address for the
VLAN1/2 into address table. Then if the LAN ports receive packets with VLAN2
addresses, the packets will be forward to the CPU via DMA. After processing the packets
(like NAT), CPU can forward the packets to VLAN1.

3.3.11 Address table access

ADM5120 provides the access of the embedded MAC address.
Read - register B+48, 4C, and 50
Write - register B+58 and 5C

3.3.12 Address security

ADM5120 supports the source MAC address security function, register B+2C.
It can check all-incoming packets in the enable ports – compare the source MAC exists
in the MAC address table or not, if not, discard the packets and report the status,
register B+18.
ADMtek Inc.
Issue the search-start command, and ADM5120 will automatically search the
embedded address table and report the valid one only.
If at the end of a table, it will also report the status.
Fill the write address and other information, like port number (or VLAN
number), age-time (or static), then issue the write command, and wait for the
write done bit.
Function Description
3-6