I have a circular network loop using MST. The switches are connected via dual gigabit fiber in an etherchannel bundle.
I had to re-run fiber connecting 2 of the switches, so I shut down the port-channel interface between them. Now that I have all of the cabling back in place, will there be any interruption of service when I re-enable the etherchannel link?
I understand that MST touts speed as one of its key selling points, but this is an extremely high availability environment and even a few seconds of downtime could be catastrophic.
In my mind, it shouldn't be any different than how MST would operate if a cable were to be removed from a switch, which is something I've tested and worked perfectly. I just can't afford any gotchas here. UDLD is enabled on both switches; aside from that all relevant information should be below.
In short, here is a simple diagram.
A--------B
| |
D--------C
The port channel interface between switch A and D is administratively shut down. When I re-enable it, will it disrupt any traffic?
Here is my configuration:
A:
MST Config:
!
spanning-tree mst configuration
name CLV-Region
revision 10
instance 1 vlan 2-6, 15, 20-23, 30, 40, 50, 100, 200
!
spanning-tree mst 0-2 priority 8192
Interface config:
CLV-MDF-SW-01#sh run int gi1/16
Building configuration...
Current configuration : 311 bytes
!
interface GigabitEthernet1/16
description CLV-IDF2-SW-01 Uplink
switchport trunk encapsulation dot1q
switchport mode trunk
service-policy output autoqos-voip-policy
qos trust cos
auto qos voip trust
tx-queue 3
bandwidth percent 33
priority high
shape percent 33
channel-group 2 mode on
end
CLV-MDF-SW-01#sh run int gi1/17
Building configuration...
Current configuration : 311 bytes
!
interface GigabitEthernet1/17
description CLV-IDF2-SW-01 Uplink
switchport trunk encapsulation dot1q
switchport mode trunk
service-policy output autoqos-voip-policy
qos trust cos
auto qos voip trust
tx-queue 3
bandwidth percent 33
priority high
shape percent 33
channel-group 2 mode on
end
CLV-MDF-SW-01#sh run int po2
Building configuration...
Current configuration : 139 bytes
!
interface Port-channel2
description CLV-IDF2-SW-01 Uplink
switchport
switchport trunk encapsulation dot1q
switchport mode trunk
end
D:
MST Config:
!
spanning-tree mode mst
spanning-tree loopguard default
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
spanning-tree mst configuration
name CLV-Region
revision 10
instance 1 vlan 2-6, 20-23, 30, 40, 100, 200
!
spanning-tree mst 0-2 priority 24576
Interface config:
!
interface GigabitEthernet0/1
description CLV-MDF-SW-01 Uplink
switchport trunk encapsulation dot1q
switchport mode trunk
shutdown
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
priority-queue out
mls qos trust cos
auto qos voip trust
channel-group 1 mode on
end
CLV-IDF2-SW-01#sh run int gi0/2
Building configuration...
Current configuration : 321 bytes
!
interface GigabitEthernet0/2
description CLV-MDF-SW-01 Uplink
switchport trunk encapsulation dot1q
switchport mode trunk
shutdown
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
priority-queue out
mls qos trust cos
auto qos voip trust
channel-group 1 mode on
end
CLV-IDF2-SW-01#sh run int po1
Building configuration...
Current configuration : 102 bytes
!
interface Port-channel1
switchport trunk encapsulation dot1q
switchport mode trunk
shutdown
end
All in all it seems like a no brainer, but I'd rather someone with more MST experience comment on this. I've goofed before by adding a VLAN and causing an instance recalculation (outage!) and would rather not have to explain something like that again.
Thanks,
Jason
