However, before making connections between switches, pay attention to:

wThe ports at both ends of a Port Aggregation connection must be configured as Aggregation Ports.

wThe ports at both ends of a Port Aggregation connection must have the same port properties, including Speed, Duplex mode.

wAll the ports of a Port Aggregation must be treated as an integer when added to/deleted from a VLAN.

wSpanning Tree Algorithm (STA) treats all the ports of a Port Aggregation as an integer.

wBefore connecting cables between switches, enable the Pot Aggregation to avoid looping.

wBefore disabling Port Aggregation, remove the connecting cables between switches to avoid looping.

wBoth two slide-in slots should use the identical modules (two coppers/two fibers) otherwise the Port Aggregation connection is invalid.

4.12STA

The Spanning Tree Algorithm (STA) outlined in IEEE 802.1D can avoid network looping but coexist with linking backup. This feature permits STA-aware switches interact with each other. This can ensure only one route exists between any two devices on the network. If looping is detected (maybe implements on purpose for linking backup), looping ports will be blocked to discard additional route. If one using route fails, this Spanning Tree Algorithm automatically releases the blocking port and establishes connection with other devices.

Since a STA network has been established, all devices listen for Hello BPDUs (Bridge Protocol Data Units) sent from the Root Bridge. After the Max Age maximum time is up, the device supposes that the route to the Root Bridge is down. The devices initiate negotiations with each other to reconfigure the network for a valid topology.

Root Device

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Designated Port

 

 

Designated Port

 

 

 

 

 

 

 

 

 

 

 

Root Port

 

Root Port

Designated Port

Blocking Route

Designated Port

 

 

Root Port

Root Port

Root Port

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