adm6999g Infineon Technologies Corporation, adm6999g Datasheet - Page 24

• Manufacturer Part Number: adm6999g
• Description: 8 Port 10/100 Mb/s + Gigabit Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

2. If the DA is an UNICAST address and the address was not found, the ADM6999G/GX treats it as a multicast
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 dropped by ADM6999G/GX.
5. ADM6999G/GX will forward the packet with DA of (01-80-C2-00-00-00), filter out the packet with DA of (01-80-
3.4.1.3
Address aging is supported for topology changes such as an address moving from one port to the other. When
this happens, the ADM6999G/GX internally has a 300 seconds timer and will age out (remove) the address from
the address table. Aging function can be enabled/disabled by users. Normally, disabling aging function is for
security purpose.
3.4.1.4
The ADM6999G/GX implements the truncated exponential back off algorithm compliant to the IEEE802.3
CSMA/CD standard. ADM6999G/GX will restart the back off algorithm by choosing 0-9 collision counts. The
ADM6999G/GX resets the collision counter after 16 consecutive retransmit trials.
3.4.1.5
IPG is the idle time between any two successive packets from the same port. The typical number is 96-bits time.
The value is 9.6µs for 10Mbps ETHERNET, and 960ns for 100Mbps fast ETHERNET. ADM6999G/GX provides
the option of a 92-bit gap in EEPROM to prevent packet loss when Flow Control is turned off and clock P.P.M.
values differ.
3.4.1.6
The ADM6999G/GX will discard all illegal frames such as small packets (less than 64 bytes), oversized packets
(greater than 1518 or 1522 bytes) and bad CRC. Dribbling packing with good CRC value will be accepted by
ADM6999G/GX. In case of bypass mode is enabled, ADM6999G/GX will support tagged and untagged packets
with size up to 1522 bytes. In case of non-bypass mode, ADM6999G/GX will support tagged packets up to
1526bytes, and untagged packets up to 1522bytes.
3.4.1.7
Back Pressure function is supported for half-duplex operation. When the ADM6999G/GX cannot allocate a
receiving buffer for an incoming packet (buffer full), the device will transmit a jam pattern on the port, thus forcing
a collision. Back Pressure is enabled by the BPEN set during RESET asserting. An Infineon-ADMtek Co Ltd
proprietary algorithm is implemented inside the ADM6999G/GX to prevent back pressure function causing HUB
partitioned under heavy traffic environment and reduce the packet lost rate to increase the whole system
performance.
3.4.1.8
When full duplex port runs out of its receiving buffer, a PAUSE packet command will be issued by ADM6999G/GX
to notice the packet sender to pause transmission. This frame based flow control is totally compliant to IEEE
802.3x. ADM6999G/GX can issue or receive pause packet.
Data Sheet
packet and forwards across the bridge.
ADM6999G/GX can issue and learn PAUSE command.
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
Back off Algorithm
Inter-Packet Gap (IPG)
Illegal Frames
Half Duplex Flow Control
Full Duplex Flow Control
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Rev 1.31, 2005-11-25
ADM6999G/GX
Descriptions