RSTP Configuration
This chapter contains a complete sample Rapid Spanning Tree Protocol (RSTP) configuration. RSTP provides rapid convergence of a spanning tree. It speeds up the reconfiguration of the tree after a change by using alternate ports.
Topology
The following example is a simple multi-bridge topology.
RSTP Topology
Note: Run the switchport command on each port to change to Layer-2 mode.
Configuration
Bridge 1
Bridge1#configure terminal | Enter configure mode. |
Bridge1(config)#bridge 1 protocol rstp | Add a bridge (1) to the rapid 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 transaction. |
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 transaction. |
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 transaction. |
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 transaction. |
Bridge1(config-if)#exit | Exit interface mode. |
Bridge 2
Bridge2#configure terminal | Enter configure mode. |
Bridge2(config)#bridge 2 protocol rstp | Add a bridge (2) to the rapid 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 transaction. |
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)#commit | Commit the transaction. |
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 transaction. |
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 transaction. |
Bridge2(config-if)#exit | Exit interface mode. |
Bridge 3
Bridge3#configure terminal | Enter configure mode. |
Bridge3(config)#bridge 3 protocol rstp | Add a bridge (3) to the rapid 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 transaction. |
Bridge3(config-if)#exit | Exit interface mode. |
Bridge3(config-if)#switchport | Configure interface as a layer 2 port. |
Bridge3(config)#interface eth3 | Enter interface mode. |
Bridge3(config-if)#bridge-group 3 | Associate the interface with bridge group 3. |
Bridge3(config-if)#commit | Commit the transaction. |
Bridge3(config-if)#exit | Exit interface mode. |
Bridge 4
Bridge4#configure terminal | Enter configure mode. |
Bridge4(config)#bridge 4 protocol rstp | Add a bridge (4) to the rapid 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 transaction. |
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 transaction. |
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 transaction. |
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 transaction. |
Bridge3(config-if)#exit |
Validation
show spanning-tree, show spanning-tree interface <if-name>
Bridge 1
#show spanning-tree
% 1: Bridge up - Spanning Tree Enabled - topology change detected
% 1: Root Path Cost 200000 - Root Port 6 - Bridge Priority 32768
% 1: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% 1: Root Id 800052540046f549
% 1: Bridge Id 80005254009cb7e6
% 1: last topology change Tue Aug 11 02:25:01 2020
% 1: 30 topology change(s) - last topology change Tue Aug 11 02:25:01 2020
% 1: portfast bpdu-filter disabled
% 1: portfast bpdu-guard disabled
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - Role Alternate - State Discarding
% eth2: Designated Path Cost 200000
% eth2: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth2: Designated Port Id 0x8004 - Priority 128 -
% eth2: Root 800052540046f549
% eth2: Designated Bridge 8000525400751db5
% eth2: Message Age 1 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 4 - Hello Timer 0 - topo change timer 0
% eth2: forward-transitions 2
% eth2: Restricted-role OFF
% eth2: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth2: Configured Link Type point-to-point - Current point-to-point
% eth2: No auto-edge configured - Current port Auto Edge off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - Role Alternate - State Discarding
% eth3: Designated Path Cost 200000
% eth3: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth3: Designated Port Id 0x8005 - Priority 128 -
% eth3: Root 800052540046f549
% eth3: Designated Bridge 8000525400751db5
% eth3: Message Age 1 - Max Age 20
% eth3: Hello Time 2 - Forward Delay 15
% eth3: Forward Timer 0 - Msg Age Timer 3 - Hello Timer 0 - topo change timer 0
% eth3: forward-transitions 3
% eth3: Restricted-role OFF
% eth3: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth3: Configured Link Type point-to-point - Current point-to-point
% eth3: No auto-edge configured - Current port Auto Edge off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - Role Rootport - State Forwarding
% eth4: Designated Path Cost 0
% eth4: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth4: Designated Port Id 0x8006 - Priority 128 -
% eth4: Root 800052540046f549
% eth4: Designated Bridge 800052540046f549
% eth4: Message Age 0 - Max Age 20
% eth4: Hello Time 2 - Forward Delay 15
% eth4: Forward Timer 0 - Msg Age Timer 3 - Hello Timer 0 - topo change timer 0
% eth4: forward-transitions 6
% eth4: Restricted-role OFF
% eth4: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth4: Configured Link Type point-to-point - Current point-to-point
% eth4: No auto-edge configured - Current port Auto Edge off
%
% eth5: Port Number 7 - Ifindex 7 - Port Id 0x8007 - Role Alternate - State Discarding
% eth5: Designated Path Cost 200000
% eth5: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth5: Designated Port Id 0x8004 - Priority 128 -
% eth5: Root 800052540046f549
% eth5: Designated Bridge 800052540065fd8c
% eth5: Message Age 1 - Max Age 20
% eth5: Hello Time 2 - Forward Delay 15
% eth5: Forward Timer 0 - Msg Age Timer 3 - Hello Timer 0 - topo change timer 0
% eth5: forward-transitions 4
% eth5: Restricted-role OFF
% eth5: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% eth5: No portfast configured - Current portfast off
% eth5: bpdu-guard default - Current bpdu-guard off
% eth5: bpdu-filter default - Current bpdu-filter off
% eth5: no root guard configured - Current root guard off
% eth5: Configured Link Type point-to-point - Current point-to-point
% eth5: No auto-edge configured - Current port Auto Edge off
%
#
Bridge 2
#show spanning-tree
% 2: Bridge up - Spanning Tree Enabled - topology change detected
% 2: Root Path Cost 200000 - Root Port 7 - Bridge Priority 32768
% 2: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% 2: Root Id 800052540046f549
% 2: Bridge Id 8000525400751db5
% 2: last topology change Tue Aug 11 02:25:00 2020
% 2: 22 topology change(s) - last topology change Tue Aug 11 02:25:00 2020
% 2: portfast bpdu-filter disabled
% 2: portfast bpdu-guard disabled
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - Role Designated - State Forwarding
% eth2: Designated Path Cost 200000
% eth2: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth2: Designated Port Id 0x8004 - Priority 128 -
% eth2: Root 800052540046f549
% eth2: Designated Bridge 8000525400751db5
% 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 3
% eth2: Restricted-role OFF
% eth2: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth2: Configured Link Type point-to-point - Current point-to-point
% eth2: No auto-edge configured - Current port Auto Edge off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - Role Designated - State Forwarding
% eth3: Designated Path Cost 200000
% eth3: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth3: Designated Port Id 0x8005 - Priority 128 -
% eth3: Root 800052540046f549
% eth3: Designated Bridge 8000525400751db5
% 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 3
% eth3: Restricted-role OFF
% eth3: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth3: Configured Link Type point-to-point - Current point-to-point
% eth3: No auto-edge configured - Current port Auto Edge off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - Role Alternate - State Discarding
% eth4: Designated Path Cost 0
% eth4: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth4: Designated Port Id 0x8007 - Priority 128 -
% eth4: Root 800052540046f549
% eth4: Designated Bridge 800052540046f549
% eth4: Message Age 0 - Max Age 20
% eth4: Hello Time 2 - Forward Delay 15
% eth4: Forward Timer 0 - Msg Age Timer 4 - Hello Timer 0 - topo change timer 0
% eth4: forward-transitions 3
% eth4: Restricted-role OFF
% eth4: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth4: Configured Link Type point-to-point - Current point-to-point
% eth4: No auto-edge configured - Current port Auto Edge off
%
% eth5: Port Number 7 - Ifindex 7 - Port Id 0x8007 - Role Rootport - State Forwarding
% eth5: Designated Path Cost 0
% eth5: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth5: Designated Port Id 0x8004 - Priority 128 -
% eth5: Root 800052540046f549
% eth5: Designated Bridge 800052540046f549
% eth5: Message Age 0 - Max Age 20
% eth5: Hello Time 2 - Forward Delay 15
% eth5: Forward Timer 0 - Msg Age Timer 4 - Hello Timer 0 - topo change timer 0
% eth5: forward-transitions 2
% eth5: Restricted-role OFF
% eth5: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% eth5: No portfast configured - Current portfast off
% eth5: bpdu-guard default - Current bpdu-guard off
% eth5: bpdu-filter default - Current bpdu-filter off
% eth5: no root guard configured - Current root guard off
% eth5: Configured Link Type point-to-point - Current point-to-point
% eth5: No auto-edge configured - Current port Auto Edge off
%
#
Bridge 3
#show spanning-tree
% 3: Bridge up - Spanning Tree Enabled - topology change detected
% 3: Root Path Cost 200000 - Root Port 5 - Bridge Priority 32768
% 3: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% 3: Root Id 800052540046f549
% 3: Bridge Id 800052540065fd8c
% 3: last topology change Tue Aug 11 02:25:00 2020
% 3: 16 topology change(s) - last topology change Tue Aug 11 02:25:00 2020
% 3: portfast bpdu-filter disabled
% 3: portfast bpdu-guard disabled
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - Role Designated - State Forwarding
% eth2: Designated Path Cost 200000
% eth2: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth2: Designated Port Id 0x8004 - Priority 128 -
% eth2: Root 800052540046f549
% eth2: Designated Bridge 800052540065fd8c
% eth2: Message Age 1 - Max Age 20
% eth2: Hello Time 2 - Forward Delay 15
% eth2: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 1 - topo change timer 0
% eth2: forward-transitions 2
% eth2: Restricted-role OFF
% eth2: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth2: Configured Link Type point-to-point - Current point-to-point
% eth2: No auto-edge configured - Current port Auto Edge off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - Role Rootport - State Forwarding
% eth3: Designated Path Cost 0
% eth3: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth3: Designated Port Id 0x8005 - Priority 128 -
% eth3: Root 800052540046f549
% eth3: Designated Bridge 800052540046f549
% eth3: Message Age 0 - Max Age 20
% eth3: Hello Time 2 - Forward Delay 15
% eth3: Forward Timer 0 - Msg Age Timer 3 - Hello Timer 0 - topo change timer 0
% eth3: forward-transitions 2
% eth3: Restricted-role OFF
% eth3: Version Rapid Spanning Tree Protocol - Receive RSTP - Send RSTP
% 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
% eth3: Configured Link Type point-to-point - Current point-to-point
% eth3: No auto-edge configured - Current port Auto Edge off
#
Bridge 4
#show spanning-tree
% 4: Bridge up - Spanning Tree Enabled - topology change detected
% 4: Root Path Cost 0 - Root Port 0 - Bridge Priority 32768
% 4: Forward Delay 15 - Hello Time 2 - Max Age 20 - Transmit Hold Count 6
% 4: Root Id 800052540046f549
% 4: Bridge Id 800052540046f549
% 4: last topology change Tue Aug 11 02:24:58 2020
% 4: 6 topology change(s) - last topology change Tue Aug 11 02:24:58 2020
% 4: portfast bpdu-filter disabled
% 4: portfast bpdu-guard disabled
% eth2: Port Number 4 - Ifindex 4 - Port Id 0x8004 - Role Designated - State Forwarding
% eth2: Designated Path Cost 0
% eth2: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth2: Designated Port Id 0x8004 - Priority 128 -
% eth2: Root 800052540046f549
% eth2: Designated Bridge 800052540046f549
% 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: Version Rapid Spanning Tree Protocol - Receive None - Send RSTP
% 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
% eth2: Configured Link Type point-to-point - Current point-to-point
% eth2: No auto-edge configured - Current port Auto Edge off
%
% eth3: Port Number 5 - Ifindex 5 - Port Id 0x8005 - Role Designated - State Forwarding
% eth3: Designated Path Cost 0
% eth3: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth3: Designated Port Id 0x8005 - Priority 128 -
% eth3: Root 800052540046f549
% eth3: Designated Bridge 800052540046f549
% 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: Version Rapid Spanning Tree Protocol - Receive None - Send RSTP
% 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
% eth3: Configured Link Type point-to-point - Current point-to-point
% eth3: No auto-edge configured - Current port Auto Edge off
%
% eth4: Port Number 6 - Ifindex 6 - Port Id 0x8006 - Role Designated - State Forwarding
% eth4: Designated Path Cost 0
% eth4: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth4: Designated Port Id 0x8006 - Priority 128 -
% eth4: Root 800052540046f549
% eth4: Designated Bridge 800052540046f549
% 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: Version Rapid Spanning Tree Protocol - Receive None - Send RSTP
% 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
% eth4: Configured Link Type point-to-point - Current point-to-point
% eth4: No auto-edge configured - Current port Auto Edge off
%
% eth5: Port Number 7 - Ifindex 7 - Port Id 0x8007 - Role Designated - State Forwarding
% eth5: Designated Path Cost 0
% eth5: Configured Path Cost 200000 - Add type Explicit ref count 1
% eth5: Designated Port Id 0x8007 - Priority 128 -
% eth5: Root 800052540046f549
% eth5: Designated Bridge 800052540046f549
% eth5: Message Age 0 - Max Age 20
% eth5: Hello Time 2 - Forward Delay 15
% eth5: Forward Timer 0 - Msg Age Timer 0 - Hello Timer 0 - topo change timer 0
% eth5: forward-transitions 1
% eth5: Restricted-role OFF
% eth5: Version Rapid Spanning Tree Protocol - Receive None - Send RSTP
% eth5: No portfast configured - Current portfast off
% eth5: bpdu-guard default - Current bpdu-guard off
% eth5: bpdu-filter default - Current bpdu-filter off
% eth5: no root guard configured - Current root guard off
% eth5: Configured Link Type point-to-point - Current point-to-point
% eth5: No auto-edge configured - Current port Auto Edge off
%
#