Hello friends, I have an spanning tree question for you!
I have a lot of switches connected between them, but I have seen
something that I can not explain very well. Two of these switches are
connected using two cables:
Switch1 Switch2
Port 29 ------------- Port 29
Port 30 ------------- Port 30
I expected to see one port in blocking state (spanning-tree) and the other
in forwarding state, but suprisingly I have seen that port 30 is in blocking
state
in Switch1 but it is in forwarding state in Switch 2. Let's see these
outputs:
Switch1#sh spanning-tree interface FastEthernet 0/29
Interface Fa0/29 (port 35) in Spanning tree 1 is FORWARDING
Port path cost 19, Port priority 128
Designated root has priority 32768, address 0002.fd3c.18b5
Designated bridge has priority 32768, address 0005.5e0c.57b6
Designated port is 35, path cost 23
Timers: message age 0, forward delay 0, hold 0
Switch1#sh spanning-tree interface FastEthernet 0/30
Interface Fa0/30 (port 36) in Spanning tree 1 is FORWARDING
Port path cost 19, Port priority 128
Designated root has priority 32768, address 0002.fd3c.18b5
Designated bridge has priority 32768, address 0005.5e0c.57b6
Designated port is 36, path cost 23
Timers: message age 0, forward delay 0, hold 0
BPDU: sent 264503, received 2
Switch2#sh spanning-tree interface FAstEthernet 0/29
Interface Fa0/29 (port 35) in Spanning tree 1 is FORWARDING
Port path cost 19, Port priority 128
Designated root has priority 32768, address 0002.fd3c.18b5
Designated bridge has priority 32768, address 0005.5e0c.57b6
Designated port is 35, path cost 23
Timers: message age 4, forward delay 0, hold 0
BPDU: sent 2, received 264561
Switch2#sh spanning-tree interface FAstEthernet 0/30
Interface Fa0/30 (port 36) in Spanning tree 1 is BLOCKING
Port path cost 19, Port priority 128
Designated root has priority 32768, address 0002.fd3c.18b5
Designated bridge has priority 32768, address 0005.5e0c.57b6
Designated port is 36, path cost 23
Timers: message age 3, forward delay 0, hold 0
BPDU: sent 2, received 264573
Why a port is in blocking state and the other is in forwarding??? I
expected to
see both ports in blocking, but one forwarding and the other blocking
doesn't make
sense!!!
Thanks a lot!
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=74594&t=74594
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