adm6996f Infineon Technologies Corporation, adm6996f Datasheet - Page 28

• Manufacturer Part Number: adm6996f
• Description: 6 Port 10/100 Mb/s Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

ADM6996F
Infineon-ADMtek Co Ltd.
3.15.2 Address Recognition and Packet Forwarding
3.15.3 Address Aging
3.15.4 Back off Algorithm
3.15.5 Inter-Packet Gap (IPG)
The ADM6996F 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 ADM6996F 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.
The ADM6996F implements the truncated exponential back off algorithm compliant to
the 802.3 CSMA-CD standard. ADM6996F will restart the back off algorithm by
choosing 0-9 collision counts. The ADM6996F resets the collision counter after 16
consecutive retransmit trials.
IPG is the idle time between any two successive packets from the same port. The typical
number is 96 bits time. The value is 9.6us for 10Mbps ETHERNET, 960ns for 100Mbps
fast ETHERNET and 96ns for 1000M. ADM6996F provide option of 92 bit gap in
EEPROM to prevent packet lost when turn off Flow Control and clock P.P.M. value
difference.
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 ADM6996F
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) ADM6996F will forward the packet with DA of ( 01-80-C2-00-00-00 ), filter out
Table, the ADM6996F will check the port number and acts as follows:
treats it as a multicast packet and forwards across the bridge.
dropped by ADM6996F. ADM6996F 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 )
ŒIf the port number is equal to the port on which the packet was received,
ŒIf the port number is different, the packet is forwarded across the bridge.
the packet is discarded.
Function Description
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