adm6995 ETC-unknow, adm6995 Datasheet - Page 26

• Manufacturer Part Number: adm6995
• Description: Port 10/100 Mb/s Single Chip Ethiernet Switch Controller
• Manufacturer: ETC-unknow

ADM6995L
ADMtek Inc.
3.15.1
3.15.2
3.15.3
The ADM6995L uses a hash algorithm to learn the MAC address and can learn up to 2K
MAC addresses. Address is stored in the Address Table. The ADM6995L searches for
the Source Address (SA) of an incoming packet in the Address Table and acts as below:
If the SA was not found in the Address Table (a new address), the ADM6995L waits
until the end of the packet (non-error packet) and updates the Address Table. If the SA
was found in the Address Table, then aging value of each corresponding entry will be
reset to 0.
When the DA is PAUSE command, then the learning process will be disabled
automatically by ADM6995L.
The ADM6995L forwards the incoming packets between bridged ports according to the
Destination Address (DA) as below. All the packet forwarding will check VLAN first.
Forwarding port must same VLAN with source port.
Address aging is supported for topology changes such as an address moving from one
port to the other. When this happens, the ADM6995L internally has a 300 seconds timer
will aged out (remove) the address from the address table. Aging function can
enable/disable by user. Normally, disabling aging function is for security purpose.
1) If the DA is an UNICAST address and the address was found in the Address
2) If the DA is an UNICAST address and the address was not found, the
3) If the DA is a Multicast address, the packet is forwarded across the bridge.
4) If the DA is PAUSE Command (01-80-C2-00-00-01), then this packet will be
5) ADM6995L will forward the packet with DA of ( 01-80-C2-00-00-00 ), filter out
Address Learning
Address Recognition and Packet Forwarding
Table, the ADM6995L will check the port number and acts as follows:
ADM6995L treats it as a multicast packet and forwards across the bridge.
dropped by ADM6995L. ADM6995L can issue and learn PAUSE command.
the packet with DA of ( 01-80-C2-00-00-01 ), and forward the packet with DA of
( 01-80-C2-00-00-02 ~ 01-80-C2-00-00-0F )
Address Aging
If the port number is equal to the port on which the packet was received,
the packet is discarded.
If the port number is different, the packet is forwarded across the bridge.
Function Description
3-10