PEF22827EL-V11 Lantiq, PEF22827EL-V11 Datasheet - Page 129

• Manufacturer Part Number: PEF22827EL-V11
• Manufacturer: Lantiq

Specifications of PEF22827EL-V11

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Adjustable Back Off Algorithm
Ethernet transmitter activity is increased by resetting the collision counter for a packet
after less than the standard 16 retries. This resets the exponential back off algorithm,
thereby allowing insertion of shorter IPGs than are possible using the algorithm specified
by the IEEE 802.3 standard.
Packets are not discarded and retransmission is continued indefinitely.
The number of retries can be set to 16, 8, 4 and 2. If back pressure is enabled, the
algorithm is limited to one retry, with a minimum back off of one IPG, regardless of the
number of retries programmed.
7.6.10.1.5 Bridging Control
The Ethernet interface learns the MAC address of attached Ethernet devices in real time.
It searches for the source address of an incoming packet in the address table. If it is not
found, the Ethernet interface waits until the end of the packet to verify that it is has no
errors, and updates the address table. The address table can be used to filter addresses
of packets whose source and destination are on the same side of a link.
The Ethernet interface forwards an incoming packet from the Ethernet link to the digital
transceiver link according to the destination address as follows:
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If an address recognition cycle fails because more than 32 addresses entered the
address table, the packet is treated as unknown and forwarded to the digital transceiver
link.
When an address moves from one side of the link to the other, the Ethernet interface
detects the change and updates its address table accordingly.
Aging can be fully automatic or triggered by the micro controller. The micro controller can
ask for invalidation of address table entries.
The Ethernet interface keeps a record of the relative age of an address by setting a bit
in the address table whenever it receives a packet. The Ethernet interface scans the
address table during programmable time intervals and resets this bit. If, in an interval,
the bit remained clear, this station did not transmit any packet in this period, and the
address is removed from the table.
The embedded controller can be programmed to trigger aging.
Preliminary Data Sheet
If the destination address is Unicast and the address is in the address table, the
packet is discarded.
If the destination address is Unicast and the address is not in the address table, the
packet is forwarded to the digital transceiver link
If the destination address is a broadcast address, the packet is forwarded on the
digital transceiver link.
129
Operation – Digital Block
Rev. 1.1, 2005-01-30
VDSL6100i
PEF 22827