STP Max Age

The Max Age is a value contained within BPDUs which are used by the Spanning Tree Protocol (STP). The full contents of a BPDU can be found here: STP contents of a BPDU.

The Max Age value has two functions:

  • It indicates the age in seconds at which time the current BPDU should be discarded. By default, this value is set to 20 but can be anything from 1 to 40.
  • It acts as a maximum value for the Message Age parameter in the BPDU.

Links:

https://community.cisco.com/t5/switching/msg-age-and-max-age-in-rstp/td-p/2251614

https://forum.networklessons.com/t/rapid-spanning-tree-configuration/1139/21?u=lagapides