stp converge

Function

The stp converge command sets the converging mode of a spanning tree protocol.

The undo stp converge command restores the default mode.

By default, the converging mode of the spanning tree protocol is normal.

Format

stp converge { fast | normal }

undo stp converge

Parameters

Parameter	Description	Value
fast	Indicates ARP entries that will be directly deleted.	-
normal	Indicates ARP entries that will age quickly.	-

Views

System view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

On a Layer 2 network running a spanning tree protocol, if the topology of a spanning tree instance changes, the forwarding paths of VLANs that are mapped to this instance change. As a result, ARP entries related to these VLANs need to be updated. Based on methods for processing ARP entries, the converging modes of a spanning tree protocol are classified into fast and normal:

In fast mode, entries that need to be updated in an ARP table are directly deleted.
In normal mode, entries that need to be updated in an ARP table quickly age. A switching device sets the EXPIRE time of these ARP entries to 0 in order to age them. If the number of detection times for aging out ARP entries is greater than 0, the switching device detects these ARP entries before deleting them.

The stp converge command can be used to set a converging mode based on the method for processing ARP entries.

Precautions

If the stp converge fast command is run on a switching device and the topology of a spanning tree instance changes, the switching device will directly delete the ARP entries that need to be updated in the ARP table.

If the stp converge normal command is run on a switching device and the topology of a spanning tree instance changes, the switching device will age the ARP entries that need to be updated in the ARP table.

Setting the converging mode of a spanning tree protocol to normal is recommended. If the fast mode is used, frequent ARP entry deletion will affect services and even may cause the CPU usage of the device to reach 100%. As a result, packet processing will time out, causing network flapping.

In either fast or normal mode, MAC address entries that need to be updated are deleted.

Example

# Set the converging mode of the spanning tree protocol on the Ethernet switch as normal.

<HUAWEI> system-view

[HUAWEI] stp converge normal