Planet Technology Planet 4-Port 10/100Mbps +1/2 100FX Fiber Port Industrial Fast Ethernet Switch ISW-621 - Manual (Page 24)

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4. SwITCh OpeRATION
4.1 Address Table
The Industrial Fast Ethernet Switch is implemented with an address
table. This address table composed of many entries. Each entry is used
to store the address information of some node in network, including
MAC address, port no, etc. This information comes from the learning
process of Industrial Fast Ethernet Switch.
4.2 Learning
When one packet comes in from any port. The Industrial Fast Ethernet
Switch will record the source address, port no. And the other related
information in address table. This information will be used to decide
either forwarding or filtering for future packets.
4.3 Forwarding & Filtering
When one packet comes from some port of the Industrial Fast Ethernet
Switch, it will also check the destination address besides the source
address learning. The Industrial Fast 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 Industrial Fast 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, then
this packet will be filtered. Thereby increasing the network throughput
and availability.
4.4 Store-and-Forward
Store-and-Forward is one type of packet-forwarding techniques. A
Store-and-Forward Industrial Switch stores the incoming frame in an
internal buffer, do the complete error checking before transmission.