Now, my two 3548 switchs each have two trunk uplink connectting to core 6509
switch,the two link are made into port channel.But I find that in one 3548, one
link's spantree status is blocking and the other is forwarding. In the other 3845s two link's spantree status is fordwarding. Why ?
the 6509 informaiton as following:
Port Mode Encapsulation Status Native vlan
4/2 nonegotiate dot1q trunking 1 (to 3548_1 G0/1)
4/3 nonegotiate dot1q trunking 1 (to 3548_2 G0/1)
5/2 nonegotiate dot1q trunking 1 (to 3548_1 G0/2)
5/3 nonegotiate dot1q trunking 1 (to 3548_2 G0/2)
Port Vlan Port-State Cost Prio Portfast Channel_id
4/2 1 forwarding 4 32 disabled 0
4/3 1 forwarding 4 32 disabled 0
5/2 1 blocking 4 32 disabled 0
5/3 1 forwarding 4 32 disabled 0
set spantree priority 8192 1
set spantree priority 8192 76
set port channel 4/2,5/2 386
set port channel 4/3,5/3 387
set trunk 4/2 nonegotiate dot1q 1-1005,1025-4094
set trunk 4/3 nonegotiate dot1q 1-1005,1025-4094
set trunk 5/2 nonegotiate dot1q 1-1005,1025-4094
set trunk 5/3 nonegotiate dot1q 1-1005,1025-4094
the 3548 informaiton as following:
sh spanning-tree interface g0/1
Interface Gi0/1 (port 67) in Spanning tree 1 is FORWARDING
Port path cost 4, Port priority 128
Designated root has priority 8192, address 0001.c74e.8000
Designated bridge has priority 32768, address 0005.32f5.8280
Designated port is 67, path cost 19
Timers: message age 0, forward delay 0, hold 0
BPDU: sent 690720, received 99
Interface Gi0/1 (port 67) in Spanning tree 76 is FORWARDING
Port path cost 4, Port priority 128
Designated root has priority 8192, address 00d0.00cf.3c4b
Designated bridge has priority 8192, address 00d0.00cf.3c4b
Designated port is 194, path cost 0
Timers: message age 1, forward delay 0, hold 0
BPDU: sent 5, received 365139
sh spanning-tree interface g0/2
Interface Gi0/2 (port 75) in Spanning tree 1 is FORWARDING
Port path cost 4, Port priority 128
Designated root has priority 8192, address 0001.c74e.8000
Designated bridge has priority 32768, address 0005.32f5.8280
Designated port is 75, path cost 19
Timers: message age 0, forward delay 0, hold 0
BPDU: sent 689667, received 14
Interface Gi0/2 (port 75) in Spanning tree 76 is BLOCKING
Port path cost 4, Port priority 128
Designated root has priority 8192, address 00d0.00cf.3c4b
Designated bridge has priority 8192, address 00d0.00cf.3c4b
Designated port is 2, path cost 0
Timers: message age 1, forward delay 0, hold 0
BPDU: sent 2, received 365135
