Enabling STP/RSTP
Context
Spanning tree calculations begin immediately after STP/RSTP is enabled on a ring network. Configurations on a switching device, such as the device priority and port priority, affect spanning tree calculation. Any change to those configurations may cause network flapping. To ensure rapid, stable spanning tree calculation, perform basic configurations on the switching device and its ports before enabling STP/RSTP.
Procedure
- Run:
system-viewThe system view is displayed.
- Run:
stp enableSTP/RSTP is enabled on the switching device.
By default, STP/RSTP is enabled on a device. If you specify a VLANIF interface of a VLAN as the management network interface for an MSTP-enabled device, you can run the ethernet-loop-protection ignored-vlan command to specify this VLAN as an ignored VLAN. Interfaces in an ignored VLAN will not enter the Blocking state and instead remain in the Forwarding state. Therefore, services will not be interrupted on these interfaces.
Follow-up Procedure
When the topology of a spanning tree changes, the forwarding paths for associated VLANs are changed. Switching devices need to update the ARP entries corresponding to those VLANs. STP/RSTP convergence mode can be set as fast or normal, which changes how the switching device processes ARP entries.
In fast mode, ARP entries to be updated are directly deleted.
In normal mode, ARP entries to be updated are rapidly aged.
In normal mode, the remaining lifetime of ARP entries is set to 0 to immediately age the ARP entries out. If the number of ARP aging probes is greater than 0, the switching device performs aging probe for these ARP entries.
Run the stp converge { fast | normal } command in the system view to configure the STP/RSTP convergence mode.
The default and recommended mode for STP/RSTP convergence is normal. If the fast mode is used, ARP entries will be frequently deleted, causing high CPU usage and network flapping.