Modifying Global ParametersThe root bridge sets the values for forward-delay, hello-time, max-age, and max-hops and overwrites the values set on other MSTPbridges.• Forward-delay — the amount of time an interface waits in the Listening state and the Learning state before it transitions to theForwarding state.• Hello-time — the time interval in which the bridge sends MSTP bridge protocol data units (BPDUs).• Max-age — the length of time the bridge maintains configuration information before it refreshes that information by recomputing theMST topology.• Max-hops — the maximum number of hops a BPDU can travel before a receiving switch discards it.NOTE: Dell Networking recommends that only experienced network administrators change MSTP parameters. Poorly plannedmodification of MSTP parameters can negatively affect network performance.To change the MSTP parameters, use the following commands on the root bridge.1 Change the forward-delay parameter.PROTOCOL MSTP modeforward-delay secondsThe range is from 4 to 30.The default is 15 seconds.2 Change the hello-time parameter.PROTOCOL MSTP modehello-time secondsNOTE: With large configurations (especially those configurations with more ports) Dell Networking recommendsincreasing the hello-time.The range is from 1 to 10.The default is 2 seconds.3 Change the max-age parameter.PROTOCOL MSTP modemax-age secondsThe range is from 6 to 40.The default is 20 seconds.4 Change the max-hops parameter.PROTOCOL MSTP modemax-hops numberThe range is from 1 to 40.The default is 20.562 Multiple Spanning Tree Protocol (MSTP)