Guys, I am having some etherchannel woes. I have the following configuration
and have just rebooted the switches to see if that would help. The task is
configure L2 etherchannel group on all switches for ports 19-24. So 19-20,
21-22, 23-24 channel-groups 1-3 respectively. I keep seeing spanning tree block
when I had thought I would not see this if etherchannel is working correctly. I
have configured and re-configured. I verified my configuration and re-booted
out of frustration. Can you take a look and see if anything is obvious to you?
port configs on all switches:
interface FastEthernet0/19
switchport trunk encapsulation isl
switchport mode trunk
channel-group 1 mode on
!
interface FastEthernet0/20
switchport trunk encapsulation isl
switchport mode trunk
channel-group 1 mode on
!
interface FastEthernet0/21
switchport trunk encapsulation isl
switchport mode trunk
channel-group 2 mode on
!
interface FastEthernet0/22
switchport trunk encapsulation isl
switchport mode trunk
channel-group 2 mode on
!
interface FastEthernet0/23
switchport trunk encapsulation isl
switchport mode trunk
channel-group 3 mode on
!
interface FastEthernet0/24
switchport trunk encapsulation isl
switchport mode trunk
channel-group 3 mode on
for example on cat 1
Fa0/19 connected trunk a-full a-100 10/100BaseTX
Fa0/20 connected trunk a-full a-100 10/100BaseTX
Fa0/21 connected trunk a-full a-100 10/100BaseTX
Port Name Status Vlan Duplex Speed Type
Fa0/22 connected trunk a-full a-100 10/100BaseTX
Fa0/23 connected trunk a-full a-100 10/100BaseTX
Fa0/24 connected trunk a-full a-100 10/100BaseTX
Gi0/1 disabled 1 auto auto 1000BaseSX
SFP
Gi0/2 disabled 1 auto auto 1000BaseSX
SFP
Po1 connected trunk a-full a-100
Po2 connected trunk a-full a-100
Po3 connected trunk a-full a-100
Cat1#sh spann block
Name Blocked Interfaces List
-------------------- ------------------------------------
VLAN0010 Po2
VLAN0020 Po2
VLAN0030 Po2
VLAN0040 Po2
VLAN0050 Po2
VLAN0060 Po2
Number of blocked ports (segments) in the system : 6
cat 2
Fa0/19 connected trunk a-full a-100 10/100BaseTX
Fa0/20 connected trunk a-full a-100 10/100BaseTX
Fa0/21 connected trunk a-full a-100 10/100BaseTX
Port Name Status Vlan Duplex Speed Type
Fa0/22 connected trunk a-full a-100 10/100BaseTX
Fa0/23 connected trunk a-full a-100 10/100BaseTX
Fa0/24 connected trunk a-full a-100 10/100BaseTX
Gi0/1 disabled 1 auto auto 1000BaseSX
SFP
Gi0/2 disabled 1 auto auto Not Present
Po1 connected trunk a-full a-100
Po2 connected trunk a-full a-100
Po3 connected trunk a-full a-100
Cat2#sh spann bloc
Name Blocked Interfaces List
-------------------- ------------------------------------
VLAN0001 Po2, Po3
Number of blocked ports (segments) in the system : 2
cat 3
Fa0/19 connected trunk a-full a-100 10/100BaseTX
Fa0/20 connected trunk a-full a-100 10/100BaseTX
Fa0/21 connected trunk a-full a-100 10/100BaseTX
Port Name Status Vlan Duplex Speed Type
Fa0/22 connected trunk a-full a-100 10/100BaseTX
Fa0/23 connected trunk a-full a-100 10/100BaseTX
Fa0/24 connected trunk a-full a-100 10/100BaseTX
Gi0/1 disabled 1 auto auto Not Present
Gi0/2 disabled 1 auto auto Not Present
Po1 connected trunk a-full a-100
Po2 connected trunk a-full a-100
Po3 connected trunk a-full a-100
Cat3#sh spann blo
Name Blocked Interfaces List
-------------------- ------------------------------------
Number of blocked ports (segments) in the system : 0
cat 4
Fa0/19 connected trunk a-full a-100 10/100BaseTX
Fa0/20 connected trunk a-full a-100 10/100BaseTX
Fa0/21 connected trunk a-full a-100 10/100BaseTX
Port Name Status Vlan Duplex Speed Type
Fa0/22 connected trunk a-full a-100 10/100BaseTX
Fa0/23 connected trunk a-full a-100 10/100BaseTX
Fa0/24 connected trunk a-full a-100 10/100BaseTX
Gi0/1 disabled 1 auto auto Not Present
Gi0/2 disabled 1 auto auto Not Present
Po1 connected trunk a-full a-100
Po2 connected trunk a-full a-100
Po3 connected trunk a-full a-100
Cat4#sh spann block
Name Blocked Interfaces List
-------------------- ------------------------------------
VLAN0001 Po1
VLAN0010 Po1, Po3
VLAN0020 Po1, Po3
VLAN0030 Po1, Po3
VLAN0040 Po1, Po3
VLAN0050 Po1, Po3
VLAN0060 Po1, Po3
Number of blocked ports (segments) in the system : 13
Didn't think spanning-tree would ever affect etherchannel like this, at least
from a blocking sense. I have done other configs where stp put the port in
err-disabled, but none of my ports are errored out as you can see..
thx guys.
Rob Routt
