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spanning tree on router in gns3
I am simulating my router as a layer 3 switch (configure slot with NM-16ESW). I have vlan10 and vlan25 and I am trying to check my spanning tree configuration. I don't see any statement in my config file like "spanning-tree mode pvst" like in the real switch. Do I have to enable the spanning-tree? If yes how? Thanks
ASKER
I am trying to simulate a 3750.
IOS 12.4(25c)
Below is the sh span output, as you can see, everything is in the forwarding state.
sw2#sh spa
VLAN10 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0001
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0001
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:25 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN10 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0001
Designated bridge has priority 32768, address cc02.0838.0001
Designated port id is 128.2, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 23
Port 4 (FastEthernet0/3) of VLAN10 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0001
Designated bridge has priority 32768, address cc04.0838.0001
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 25, received 1
VLAN25 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0002
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0002
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:31 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN25 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0002
Designated bridge has priority 32768, address cc02.0838.0002
Designated port id is 128.2, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 26
Port 4 (FastEthernet0/3) of VLAN25 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0002
Designated bridge has priority 32768, address cc04.0838.0002
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 28, received 1
VLAN200 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0003
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0003
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:37 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN200 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0003
Designated bridge has priority 32768, address cc02.0838.0003
Designated port id is 128.2, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 30
Port 4 (FastEthernet0/3) of VLAN200 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0003
Designated bridge has priority 32768, address cc04.0838.0003
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 32, received 1
IOS 12.4(25c)
Below is the sh span output, as you can see, everything is in the forwarding state.
sw2#sh spa
VLAN10 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0001
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0001
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:25 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN10 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0001
Designated bridge has priority 32768, address cc02.0838.0001
Designated port id is 128.2, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 23
Port 4 (FastEthernet0/3) of VLAN10 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0001
Designated bridge has priority 32768, address cc04.0838.0001
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 25, received 1
VLAN25 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0002
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0002
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:31 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN25 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0002
Designated bridge has priority 32768, address cc02.0838.0002
Designated port id is 128.2, designated path cost 0
Timers: message age 2, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 26
Port 4 (FastEthernet0/3) of VLAN25 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0002
Designated bridge has priority 32768, address cc04.0838.0002
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 28, received 1
VLAN200 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address cc04.0838.0003
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32768, address cc02.0838.0003
Root port is 2 (FastEthernet0/1), cost of root path is 19
Topology change flag set, detected flag not set
Number of topology changes 1 last change occurred 00:00:37 ago
from FastEthernet0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Port 2 (FastEthernet0/1) of VLAN200 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.2.
Designated root has priority 32768, address cc02.0838.0003
Designated bridge has priority 32768, address cc02.0838.0003
Designated port id is 128.2, designated path cost 0
Timers: message age 1, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 3, received 30
Port 4 (FastEthernet0/3) of VLAN200 is forwarding
Port path cost 19, Port priority 128, Port Identifier 128.4.
Designated root has priority 32768, address cc02.0838.0003
Designated bridge has priority 32768, address cc04.0838.0003
Designated port id is 128.4, designated path cost 19
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
BPDU: sent 32, received 1
That show that spanning tree is enable.
According to the below PVST+ is default on 3750 and show run/start will not show default values.
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/commmand/reference/cli3.html#wp1946050
According to the below PVST+ is default on 3750 and show run/start will not show default values.
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/commmand/reference/cli3.html#wp1946050
ASKER
I am running a 3640 router as a layer 3 switch. I don't have a 3750 switch in GNS3. Thx
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What level of IOS?
Typically spanning tree is enabled by default. What happens when you issue "show spanning-tree"?