Allied Telesis 2.6.1 manual Configuring STP

88 AT-8800 Series Switch User Guide

To specify whether the STP will operate in STANDARD mode or RAPID mode, use the command:

SET STP={stp-nameALL} [MODE={STANDARDRAPID}] [other

parameters]

The default is STANDARD. If the mode is changed while the algorithm is running then the STP is re-initialised.

To display the STP state of the switch ports (Figure 19 on page 94), use the command:

SHOW STP[={stp-nameALL}] PORT={port-listALL}

A Rapier switch in default LAN configuration has a default Spanning Tree enabled, spanning only a single default VLAN, to which all ports belong. The switches in the LAN run a distributed Spanning Tree Algorithm to create a single Spanning Tree. In a network of Rapier switches with VLANs configured, all VLANs belong by default to a default Spanning Tree called default. Multiple Spanning Trees can be created with each Spanning Tree encompassing multiple VLANs (in networks switched exclusively by Rapier switches).

For more information about multiple spanning trees, see the Switching chapter in the Rapier Switch Software Reference.

Configuring STP

By default, the switch has one default STP which cannot be destroyed. In most situations this default STP will suffice.

By default, all VLANs, and therefore all ports, belong to the default STP. To add or delete a VLAN and all the ports belonging to it from any other STP, use the commands:

ADD STP=stpname VLAN={vlan-name2..4094}

DELETE STP=stpname VLAN={vlan-name2..4094ALL}

The default STP is disabled by default at switch start up, and STPs created by a user are disabled by default when they are created. An STP must be enabled before STP can be enabled or disabled on particular ports belonging to it. To enable or disable STPs, use the commands:

ENABLE STP{=stpnameALL}

DISABLE STP={stpnameALL}

The Spanning Tree Protocol uses three configurable parameters for the time intervals that control the flow of STP information on which the dynamic STP topology depends: the HELLOTIME, FORWARDDELAY and MAXAGE parameters. All switches in the same spanning tree topology must use the same values for these parameters, but can themselves be configured with different, and potentially incompatible time intervals. The parameter values actually used by each switch are those sent by the root bridge, and forwarded to all other switches by the designated bridges.

The FORWARDDELAY parameter sets the time, in seconds, used to control how fast a port changes its spanning state when moving towards the Forwarding state. The value determines how long the port stays in each of the Listening and Learning states which precede the Forwarding state. This value is only used when the switch is acting as the Root Bridge. Any switch not acting as the Root Bridge uses a dynamic value for the FORWARDDELAY set

Software Release 2.6.1 C613-02039-00 REV A