82device that received it. This prevents devices beyond the reach of the maximum hop from participate inspanning tree calculation, so the size of the MST region is limited.Make this configuration on the root bridge only. All other devices in the MST region use the maximumhop value set for the root bridge.To configure the maximum number of hops of an MST region:Step Command Remarks1. Enter system view. system-view N/A2. Configure the maximum hopsof the MST region. stp max-hops hops 20 by default.Configuring the network diameter of a switchednetworkAny two terminal devices in a switched network are connected through a specific path composed of aseries of devices. The network diameter is the number of devices on the path composed of the mostdevices. The network diameter is a parameter that indicates the network size. A bigger network diameterindicates a larger network size. Based on the network diameter you configured, the system automaticallysets an optimal hello time, forward delay, and max age for the device.To configure the network diameter of a switched network:Step Command Remarks1. Enter system view. system-view N/A2. Configure the networkdiameter of the switchednetwork.• In STP/RSTP/MSTP mode:stp bridge-diameter diameter• In PVST mode:stp vlan vlan-list bridge-diameter diameterUse one of thecommands.The default setting is 7.NOTE:• In STP/RSTP/MSTP mode, each MST region is considered as a device and the configured networkdiameter takes effect only on the CIST (or the common root bridge), but not on the MSTIs.• In PVST mode, the network diameter configuration takes effect on the root bridge only.Configuring spanning tree timersThe following timers are used for spanning tree calculation:• Forward delayIt is the delay time for port state transition. To prevent temporary loops on a network, the spanningtree sets an intermediate port state, the learning state, before it transits from the discarding state tothe forwarding state, and requires that the port transits its state after a forward delay timer to makesure that the state transition of the local port keeps synchronized with the peer.• Hello time
