Wavetronix Click 342 (lean managed ethernet switch) (CLK-342) Manual de usuario descargar pdf (Pagina 21)

20 CHAPTER 1  CLICK 340/341/342 MANAGED SWITCHES

Frame Switching

e managed switch operates in store-and-forward mode. When receiving a data packet,

the switch analyzes the source and destination addresses. e 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

e switch learns all the source addresses for each port. Only the following packets are

forwarded to the destination address eld via the relevant port:

 Unknown source addresses

 A source address for this port

 A multicast/broadcast address

e switch can learn up to 1023 addresses. is 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

e 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 specied device (if the address could be learned beforehand).

e managed switch can learn up to 1023 addresses and stores them in its table. e switch

monitors the age of the learned addresses and automatically deletes address entries from its

address table that have exceeded a specic age (48 seconds, aging time).

Note

All learned entries are deleted on a restart.

e following is a owchart for learning addresses using the example of unicast addresses

(see Figure 2.7).

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 75 76

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Wavetronix Click 342 (lean managed ethernet switch) (CLK-342) Manual de usuario Pagina 21