Configure Spanning Tree Timers

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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.

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.

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#

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#

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#