Wavetronix Click 342 (lean managed ethernet switch) (CLK-342) - Managed Switches User Guide - Manual (Page 21)

20 CHAPTER 1 • CLICK 340/341/342 MANAGED SWITCHES
Frame Switching
The managed switch operates in store-and-forward mode. When receiving a data packet,
the switch analyzes the source and destination addresses. The switch stores up to 1023 MAC
addresses with an aging time of 48 seconds in its address table.
Store-and-Forward
All data telegrams that are received by the switch are saved and their validity is checked.
Invalid or faulty data packets ( > 1522 bytes or CRC errors) and fragments ( < 64 bytes) are
rejected. Valid data telegrams are forwarded by the switch.
Multi-Address Function
The switch learns all the source addresses for each port. Only the following packets are
forwarded to the destination address field via the relevant port:
˽ Unknown source addresses
˽ A source address for this port
˽ A multicast/broadcast address
The switch can learn up to 1023 addresses. This is important when more than one termina-
tion device is connected to one or more ports. In this way, several independent subnetworks
can be connected to one switch.
Learning Addresses
The managed switch independently learns the addresses for termination devices, which are
connected via a port, by evaluating the source addresses in the data telegram. When the
managed switch receives a data telegram, it only forwards this data telegram to the port that
connects to the specified device (if the address could be learned beforehand).
The managed switch can learn up to 1023 addresses and stores them in its table. The switch
monitors the age of the learned addresses and automatically deletes address entries from its
address table that have exceeded a specific age (48 seconds, aging time).
Note
All learned entries are deleted on a restart.
The following is a flowchart for learning addresses using the example of unicast addresses
(see Figure 2.7).