STP Configuration

This section describes how to configure STP on the device, using one of the following methods:

• STP (802.1D) Configuration
• RSTP (802.1w) Configuration

STP (802.1D) Configuration

To enable STP on a bridge, run the following command:
$ ip link set dev br0 type bridge stp_state 1

By default, STP is disabled.

• To disable STP on a bridge, set stp_state to “0”.
• To show the current stp_state value, run the following command:
  $ ip -d link show dev br0 | grep stp_state

In addition, to show extended STP configuration on the bridge (bridge stp state, port stp state, …), you can use brctl utility.
$ brctl showstp br0

You can use brctl to configure the following spanning tree protocol parameters. For more information on these parameters, see the IEEE 802.1d specification. See brctl man for details on bridge STP configurations:

• Bridge priority
• Path priority and cost
• Forwarding delay
• Hello time
• Max age

RSTP (802.1w) Configuration

RSTP support requires user-level daemon mstpd, running in RSTP mode. The mstpd daemon is an open source project (https://github.com/mstpd/mstpd).
The mstpctl utility, provided by the mstpd service, configures STP.

After the bridge is created and STP is enabled (described above), you can switch the bridge mode from STP to RSTP using the mstpctl application. See mstpctl man for more information.

• To switch the bridge mode from STP to RSTP:
  $ mstpctl setforcevers br0 rstp
• To show information about the bridge:
  $ mstpctl showbridge
• To show port information:
  $ mstpctl showport br0 sw1p5

STP Limitations

• STP is configured by means of standard Linux command line tools (ip bridge, brctl).
• To enable RSTP requires user-level daemon mstpd which should be run in RSTP mode. mstpctl is a utility to configure mstpd. mstpd(mstpctl) is not a standard Linux utility.