Spanning Tree Protocol Configuration
This chapter contains a complete sample Spanning Tree Protocol (STP) configuration.
Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for Ethernet networks. The basic function of STP is to prevent bridge loops. Spanning tree also allows a network design to include redundant links to provide automatic backup paths if an active link fails, thus, eliminating the need to manually enable or disable the backup links.
Topology
The following example is a simple multi-bridge topology.
STP Topology
Note: Run the switchport command on each port to change to Layer-2 mode.
Configurations
Bridge 1
Bridge1#configure terminal | Enter configure mode. |
Bridge1(config)#bridge 1 protocol ieee | Add a bridge (1) to the spanning tree table |
Bridge1(config)#interface eth2 | Enter interface mode. |
Bridge1(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge1(config-if)#bridge-group 1 | Associate the interface with bridge group 1. |
Bridge1(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge1(config-if)#exit | Exit interface mode. |
Bridge1(config)#interface eth3 | Enter interface mode. |
Bridge1(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge1(config-if)#bridge-group 1 | Associate the interface with bridge group 1. |
Bridge1(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge1(config-if)#exit | Exit interface mode. |
Bridge1(config)#interface eth4 | Enter interface mode. |
Bridge1(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge1(config-if)#bridge-group 1 | Associate the interface with bridge group 1. |
Bridge1(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge1(config-if)#exit | Exit interface mode. |
Bridge1(config)#interface eth5 | Enter interface mode |
Bridge1(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge1(config-if)#bridge-group 1 | Associate the interface with bridge group 1. |
Bridge1(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge1(config-if)#exit | Exit interface mode. |
Bridge 2
Bridge2#configure terminal | Enter configure mode. |
Bridge2(config)#bridge 2 protocol ieee | Add a bridge (2) to the spanning tree table |
Bridge2(config)#interface eth2 | Enter interface mode. |
Bridge2(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge2(config-if)#bridge-group 2 | Associate the interface with bridge group 2. |
Bridge2(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge2(config-if)#exit | Exit interface mode. |
Bridge2(config)#interface eth3 | Enter interface mode. |
Bridge2(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge2(config-if)#bridge-group 2 | Associate the interface with bridge group 2. |
Bridge2(config-if)#exit | Exit interface mode. |
Bridge2(config)#interface eth4 | Enter interface mode. |
Bridge2(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge2(config-if)#bridge-group 2 | Associate the interface with bridge group 2. |
Bridge2(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge2(config-if)#exit | Exit interface mode. |
Bridge2(config)#interface eth5 | Enter interface mode |
Bridge2(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge2(config-if)#bridge-group 2 | Associate the interface with bridge group 2. |
Bridge2(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge2(config-if)#exit | Exit interface mode. |
Bridge 4
Bridge4#configure terminal | Enter configure mode. |
Bridge4(config)#bridge 4 protocol ieee | Add a bridge (4) to the spanning tree table |
Bridge4(config)#interface eth2 | Enter interface mode. |
Bridge4(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge4(config-if)#bridge-group 4 | Associate the interface with bridge group 4. |
Bridge4(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge4(config-if)#exit | Exit interface mode. |
Bridge4(config)#interface eth3 | Enter interface mode. |
Bridge4(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge4(config-if)#bridge-group 4 | Associate the interface with bridge group 4. |
Bridge4(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge4(config-if)#exit | Exit interface mode. |
Bridge4(config)#interface eth4 | Enter interface mode. |
Bridge4(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge4(config-if)#bridge-group 4 | Associate the interface with bridge group 4. |
Bridge4(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge4(config-if)#exit | Exit interface mode. |
Bridge4(config)#interface eth5 | Enter interface mode |
Bridge4(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge4(config-if)#bridge-group 4 | Associate the interface with bridge group 4. |
Bridge4(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge4(config-if)#exit | Exit interface mode. |
Bridge 3
Bridge3#configure terminal | Enter configure mode. |
Bridge3(config)#bridge 3 protocol ieee | Add a bridge (3) to the spanning tree table |
Bridge3(config)#interface eth2 | Enter interface mode. |
Bridge3(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge3(config-if)#bridge-group 3 | Associate the interface with bridge group 3. |
Bridge3(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge3(config-if)#exit | Exit interface mode. |
Bridge3(config)#interface eth3 | Enter interface mode. |
Bridge3(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge3(config-if)#bridge-group 3 | Associate the interface with bridge group 3. |
Bridge3(config-if)#commit | Commit the candidate configuration to the running configuration. |
Bridge3(config-if)#exit | Exit interface mode. |
Validation
Bridge 1
#show spanning-tree
% 1: Bridge up - Spanning Tree Enabled
% 1: Root Path Cost 0 - Priority 32768
% 1: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 0
% 1: Root Id 80005254000be278
% 1: Bridge Id 80005254000be278
% 1: 15 topology changes - last topology change Sat Jul 10 09:44:56 2021
% 1: portfast bpdu-filter disabled
% 1: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8003 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
%
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - path cost 250 - designated cost 0
% eth2: Designated Port Id 0x8004 - state Forwarding -Priority 128
% eth2: Designated root 80005254000be278
% eth2: Designated Bridge 80005254000be278
% eth2: Message Age 0 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth2: forward-transitions 1
% eth2: Restricted-role OFF
% eth2: No portfast configured - Current portfast off
% eth2: bpdu-guard default - Current bpdu-guard off
% eth2: bpdu-filter default - Current bpdu-filter off
% eth2: no root guard configured - Current root guard off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - path cost 250 - designated cost 0
% eth3: Designated Port Id 0x8005 - state Forwarding -Priority 128
% eth3: Designated root 80005254000be278
% eth3: Designated Bridge 80005254000be278
% eth3: Message Age 0 - Max Age 20
% eth3: Hello Time 2 - Forward Delay 15
% eth3: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth3: forward-transitions 1
% eth3: Restricted-role OFF
% eth3: No portfast configured - Current portfast off
% eth3: bpdu-guard default - Current bpdu-guard off
% eth3: bpdu-filter default - Current bpdu-filter off
% eth3: no root guard configured - Current root guard off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - path cost 250 - designated cost 0
% eth4: Designated Port Id 0x8006 - state Forwarding -Priority 128
% eth4: Designated root 80005254000be278
% eth4: Designated Bridge 80005254000be278
% eth4: Message Age 0 - Max Age 20
% eth4: Hello Time 2 - Forward Delay 15
% eth4: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth4: forward-transitions 1
% eth4: Restricted-role OFF
% eth4: No portfast configured - Current portfast off
% eth4: bpdu-guard default - Current bpdu-guard off
% eth4: bpdu-filter default - Current bpdu-filter off
% eth4: no root guard configured - Current root guard off
%
% Default: Bridge up - Spanning Tree Enabled
% Default: Root Path Cost 0 - Root Port 0 - Bridge Priority 32768
% Default: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% Default: Root Id 8000000000000000
% Default: Bridge Id 8000000000000000
% Default: last topology change Thu Jan 1 00:00:00 1970
% Default: 0 topology change(s) - last topology change Thu Jan 1 00:00:00 1970
% Default: portfast bpdu-filter disabled
% Default: portfast bpdu-guard disabled
#show spanning-tree interface eth1
% 1: Bridge up - Spanning Tree Enabled
% 1: Root Path Cost 0 - Priority 32768
% 1: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 0
% 1: Root Id 80005254000be278
% 1: Bridge Id 80005254000be278
% 1: 15 topology changes - last topology change Sat Jul 10 09:44:56 2021
% 1: portfast bpdu-filter disabled
% 1: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8003 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
Bridge 2
#show spanning-tree
% 2: Bridge up - Spanning Tree Enabled
% 2: Root Path Cost 250 - Priority 32768
% 2: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 2: Root Id 80005254000be278
% 2: Bridge Id 8000525400b210cd
% 2: 5 topology changes - last topology change Sat Jul 10 09:44:30 2021
% 2: portfast bpdu-filter disabled
% 2: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8003 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 18 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
%
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - path cost 250 - designated cost 0
% eth2: Designated Port Id 0x8004 - state Blocked -Priority 128
% eth2: Designated root 80005254000be278
% eth2: Designated Bridge 80005254000be278
% eth2: Message Age 0 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 17 - Hello Timer 0 - topo change timer 0
% eth2: forward-transitions 0
% eth2: Restricted-role OFF
% eth2: No portfast configured - Current portfast off
% eth2: bpdu-guard default - Current bpdu-guard off
% eth2: bpdu-filter default - Current bpdu-filter off
% eth2: no root guard configured - Current root guard off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - path cost 250 - designated cost 250
% eth3: Designated Port Id 0x8005 - state Blocked -Priority 128
% eth3: Designated root 80005254000be278
% eth3: Designated Bridge 800052540047dc01
% eth3: Message Age 3 - Max Age 20
% eth3: Hello Time 2 - Forward Delay 15
% eth3: Forward Timer 0 - Msg Age Timer 13 - Hello Timer 0 - topo change timer 0
% eth3: forward-transitions 1
% eth3: Restricted-role OFF
% eth3: No portfast configured - Current portfast off
% eth3: bpdu-guard default - Current bpdu-guard off
% eth3: bpdu-filter default - Current bpdu-filter off
% eth3: no root guard configured - Current root guard off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - path cost 250 - designated cost 250
% eth4: Designated Port Id 0x8006 - state Blocked -Priority 128
% eth4: Designated root 80005254000be278
% eth4: Designated Bridge 800052540047dc01
% eth4: Message Age 3 - Max Age 20
% eth4: Hello Time 2 - Forward Delay 15
% eth4: Forward Timer 0 - Msg Age Timer 13 - Hello Timer 0 - topo change timer 0
% eth4: forward-transitions 1
% eth4: Restricted-role OFF
% eth4: No portfast configured - Current portfast off
% eth4: bpdu-guard default - Current bpdu-guard off
% eth4: bpdu-filter default - Current bpdu-filter off
% eth4: no root guard configured - Current root guard off
%
% Default: Bridge up - Spanning Tree Enabled
% Default: Root Path Cost 0 - Root Port 0 - Bridge Priority 32768
% Default: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% Default: Root Id 8000000000000000
% Default: Bridge Id 8000000000000000
% Default: last topology change Thu Jan 1 00:00:00 1970
% Default: 0 topology change(s) - last topology change Thu Jan 1 00:00:00 1970
% Default: portfast bpdu-filter disabled
% Default: portfast bpdu-guard disabled
#show spanning-tree interface eth1
% 2: Bridge up - Spanning Tree Enabled
% 2: Root Path Cost 250 - Priority 32768
% 2: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 2: Root Id 80005254000be278
% 2: Bridge Id 8000525400b210cd
% 2: 5 topology changes - last topology change Sat Jul 10 09:44:30 2021
% 2: portfast bpdu-filter disabled
% 2: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8003 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 17 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
Bridge 3
#sho spanning-tree
% 3: Bridge up - Spanning Tree Enabled
% 3: Root Path Cost 250 - Priority 32768
% 3: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 3: Root Id 80005254000be278
% 3: Bridge Id 8000525400686eb9
% 3: 2 topology changes - last topology change Sat Jul 10 09:37:36 2021
% 3: portfast bpdu-filter disabled
% 3: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8005 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 18 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
%
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - path cost 250 - designated cost 250
% eth2: Designated Port Id 0x8004 - state Forwarding -Priority 128
% eth2: Designated root 80005254000be278
% eth2: Designated Bridge 8000525400686eb9
% eth2: Message Age 1 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth2: forward-transitions 1
% eth2: Restricted-role OFF
% eth2: No portfast configured - Current portfast off
% eth2: bpdu-guard default - Current bpdu-guard off
% eth2: bpdu-filter default - Current bpdu-filter off
% eth2: no root guard configured - Current root guard off
%
% Default: Bridge up - Spanning Tree Enabled - topology change detected
% Default: Root Path Cost 0 - Root Port 0 - Bridge Priority 32768
% Default: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% Default: Root Id 8000000000000000
% Default: Bridge Id 8000000000000000
% Default: last topology change Sat Jul 10 09:37:04 2021
% Default: 1 topology change(s) - last topology change Sat Jul 10 09:37:04 2021
% Default: portfast bpdu-filter disabled
% Default: portfast bpdu-guard disabled
# show spanning-tree interface eth1
% 3: Bridge up - Spanning Tree Enabled
% 3: Root Path Cost 250 - Priority 32768
% 3: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 3: Root Id 80005254000be278
% 3: Bridge Id 8000525400686eb9
% 3: 2 topology changes - last topology change Sat Jul 10 09:37:36 2021
% 3: portfast bpdu-filter disabled
% 3: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8005 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 17 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
Bridge 4
#show spanning-tree
% 4: Bridge up - Spanning Tree Enabled
% 4: Root Path Cost 250 - Priority 32768
% 4: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 4: Root Id 80005254000be278
% 4: Bridge Id 800052540047dc01
% 4: 4 topology changes - last topology change Sat Jul 10 09:44:56 2021
% 4: portfast bpdu-filter disabled
% 4: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8006 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 17 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
%
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - path cost 250 - designated cost 250
% eth2: Designated Port Id 0x8004 - state Forwarding -Priority 128
% eth2: Designated root 80005254000be278
% eth2: Designated Bridge 800052540047dc01
% eth2: Message Age 1 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth2: forward-transitions 1
% eth2: Restricted-role OFF
% eth2: No portfast configured - Current portfast off
% eth2: bpdu-guard default - Current bpdu-guard off
% eth2: bpdu-filter default - Current bpdu-filter off
% eth2: no root guard configured - Current root guard off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - path cost 250 - designated cost 250
% eth3: Designated Port Id 0x8005 - state Forwarding -Priority 128
% eth3: Designated root 80005254000be278
% eth3: Designated Bridge 800052540047dc01
% eth3: Message Age 1 - Max Age 20
% eth3: Hello Time 2 - Forward Delay 15
% eth3: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth3: forward-transitions 1
% eth3: Restricted-role OFF
% eth3: No portfast configured - Current portfast off
% eth3: bpdu-guard default - Current bpdu-guard off
% eth3: bpdu-filter default - Current bpdu-filter off
% eth3: no root guard configured - Current root guard off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - path cost 250 - designated cost 250
% eth4: Designated Port Id 0x8006 - state Forwarding -Priority 128
% eth4: Designated root 80005254000be278
% eth4: Designated Bridge 800052540047dc01
% eth4: Message Age 1 - Max Age 20
% eth4: Hello Time 2 - Forward Delay 15
% eth4: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth4: forward-transitions 1
% eth4: Restricted-role OFF
% eth4: No portfast configured - Current portfast off
% eth4: bpdu-guard default - Current bpdu-guard off
% eth4: bpdu-filter default - Current bpdu-filter off
% eth4: no root guard configured - Current root guard off
%
# show spanning-tree interface eth1
% 4: Bridge up - Spanning Tree Enabled
% 4: Root Path Cost 250 - Priority 32768
% 4: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6 - Root port 3
% 4: Root Id 80005254000be278
% 4: Bridge Id 800052540047dc01
% 4: 4 topology changes - last topology change Sat Jul 10 09:44:56 2021
% 4: portfast bpdu-filter disabled
% 4: portfast bpdu-guard disabled
% eth1: Port Number 3 - Ifindex 3 - Port Id 0x8003 - path cost 250 - designated cost 0
% eth1: Designated Port Id 0x8006 - state Forwarding -Priority 128
% eth1: Designated root 80005254000be278
% eth1: Designated Bridge 80005254000be278
% eth1: Message Age 0 - Max Age 20
% eth1: Hello Time 2 - Forward Delay 15
% eth1: Forward Timer 0 - Msg Age Timer 18 - Hello Timer 0 - topo change timer 0
% eth1: forward-transitions 1
% eth1: Restricted-role OFF
% eth1: No portfast configured - Current portfast off
% eth1: bpdu-guard default - Current bpdu-guard off
% eth1: bpdu-filter default - Current bpdu-filter off
% eth1: no root guard configured - Current root guard off
%
%