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| Sun Ethernet Fabric Operating System ### PVRST+ Administration Guide

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## Configure Spanning Tree Timers

Configure these variables:

Variable | Description
--- | ---
`forward-time` | Controls how fast a port changes its spanning tree state from blocking to forwarding.
`hello-time` | Determines how often the switch broadcasts its hello message to other switches. If a bridge is the root bridge for a topology, then all of the bridges in that topology use the value of the hello time from the root bridge to broadcast their hello message.
`max-age` | Controls the maximum time for the STP information to be retained before it is discarded.

1. Configure the spanning tree timer (11 in this example).

       NEM-1 SEFOS# configure terminal
       NEM-1 SEFOS(config)# spanning-tree vlan 10 forward-time 11

       Forward Time for the given instance is set

       NEM-1 SEFOS(config)# end
       NEM-1 SEFOS#

   The forward-time range is 4 to 30 seconds. The default value is 15 seconds.

2. Review the spanning tree properties.

       NEM-1 SEFOS# show spanning-tree vlan 10

       -------------------------------------------------------------------
       Spanning-tree for VLAN 10

       We are the root of the Spanning Tree
       Root Id         Priority   32778
                       Address    00:14:4f:6c:56:6f
                       Cost       0
                       Port       0
                       Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 11 Sec

       Spanning Tree Enabled Protocol PVRST
       Bridge Id       Priority 32778
                       Address 00:14:4f:6c:56:6f
                       Hello Time 2 sec, Max Age 20 sec, Forward Delay 11 sec
       Name     Role         State        Cost     Prio   Type
       ----     ----         -----        ----     ----   ------
       Ex0/3    Designated   Forwarding   2000     128    P2P
       Ex0/7    Designated   Forwarding   2000     128    P2P
       Ex0/20   Designated   Forwarding   2000     128    P2P

       NEM-1 SEFOS#

3. Reset the spanning tree timer to its default value.

       NEM-1 SEFOS# configure terminal
       NEM-1 SEFOS(config)# no spanning-tree vlan 10 forward-time

       Forward Time for the given instance is set

       NEM-1 SEFOS(config)# end
       NEM-1 SEFOS#

4. Reviewing the spanning tree properties after resetting the forward timer to the default.

       NEM-1 SEFOS# show spanning-tree vlan 10

       -------------------------------------------------------------------
       Spanning-tree for VLAN 10

       We are the root of the Spanning Tree
       Root Id         Priority   32778
                       Address    00:14:4f:6c:56:6f
                       Cost       0
                       Port       0
                       Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
       Spanning Tree Enabled Protocol PVRST
       Bridge Id       Priority 32778
                       Address 00:14:4f:6c:56:6f
                       Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
       Name     Role         State        Cost     Prio   Type
       ----     ----         -----        ----     ----   ------
       Ex0/3    Designated   Forwarding   2000     128    P2P
       Ex0/7    Designated   Forwarding   2000     128    P2P
       Ex0/20   Designated   Forwarding   2000     128    P2P

       NEM-1 SEFOS#

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