stp converge

Function

The stp converge command sets a convergence mode for a spanning tree protocol.

The undo stp converge command restores the default mode.

By default, the convergence mode is normal.

Format

stp converge { fast | normal }

undo stp converge

Parameters

Parameter	Description	Value
fast	Directly deletes ARP entries.	-
normal	Ages ARP entries quickly.	-

Parameter

Description

Value

fast

Directly deletes ARP entries.

normal

Ages ARP entries quickly.

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mstp	write

Usage Guidelines

Usage Scenario

On a Layer 2 network running STP, 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. Two methods are available:

fast: Entries that need to be updated in an ARP table are directly deleted.
normal: Entries that need to be updated in an ARP table are quickly aged out. The lifetime of these ARP entries is set to 0. If the number of aging detection times is greater than 0, the device sends ARP probe packets before aging them.
To set a convergence mode based on the method for processing ARP entries, run the stp converge command.

Configuration Impact

If the stp converge fast command is run and the topology of a spanning tree instance changes, ARP entries that need to be updated are directly deleted from the ARP table.

If the stp converge normal command is run and the topology of a spanning tree instance changes, ARP entries that need to be updated are aged out in the ARP table.

Precautions

Setting the convergence mode 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 device to reach 100%. As a result, packet processing times 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 a spanning tree protocol as normal.

<HUAWEI> system-view
[~HUAWEI] stp converge normal