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4. Switch Operation
4.1 MAC Address Table and Learning
The switching hub is implemented with a MAC address table which is composed of
many entries. Each entry is used to store the address information of network nodes on
the network, including MAC address, port ID, etc. The information is the most important
base to do packet filtering and forwarding.
When one packet comes in from any port, the switching hub will learn the source
address, port ID, and the other related information in address table. Therefore, the
content of the MAC table will update dynamically.
4.2 Filtering and Forwarding
When one packet comes in from any port of the switching hub, it will check the
destination address besides the source address learning. The hub will look up 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. If found, and the destination
address is located at different port from this packet comes in, the packet will be
forwarded to the port where this destination address is located according to the
information of address table. But, if the destination address is located at the same port as
this packet comes in then this packet will be filtered.
4.3 Store and Forward
Store-and-forward is one kind of packet-forwarding methodology. As a
store-and-forward switching hub, it will store the complete packet in the internal buffer
and do the complete error checking before transmitting to the network. Therefore, no
error packets will disturb the network. It is the best choice when a network needs
efficiency and stability.
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Network Specifications
Power
