Appendix B Switch Operation; Address Table; Addres Table; Learning - Planet SW-501 User Manual

Appendix B SWITCH OPERATION

Address Table

The Switch is implemented with an address table. This address table
composed of many entries. Each entry is used to store the address infor-
mation of some node in network, including MAC address, port no, etc. The
information comes from the learning process of Ethernet Switch.

Learning

When one packet comes in from any port, the Ethernet Switch will record
the source address, port no. and the other related information in address
table. These information will be used to decide either forwarding or filtering
for future packets.
Forwarding & Filtering
When one packet comes from some port of the Ethernet Switch, it will also
check the destination address besides the source address learning. The
Ethernet Switch will lookup the address table for the destination address. If
not found, this packet will be forwarded to all the other ports except the port
which this packet comes in. And these ports will transmit this packet to the
network it connected. If found, and the destination address is located at
different port from this packet comes in, the Ethernet Switch will forward
this packet to the port where this destination address is located according
to the information from address table. But, if the destination address is
located at the same port with this packet comes in, when this packet will be
filtered. Thereby increasing the network throughput and availability

Store-and-Forward

Store-and-Forward is one type of packet-forwarding techniques. A
Store-and-Forward Ethernet Switch stores the incoming frame in an inter-
nal buffer, do the complete error checking before transmission. Therefore,
no error packets occurrence, it is the best choice when a network needs
efficiency and stability. The Switch scans the destination address from the
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