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October 19th, 2020 23:00

Setting bpduguard on edge port-channels?

We are using dell S4048-ON switches in VLT setup to connect our servers in port-channel setup. We noticed that port flapping of interfaces sends out spanning tree changes throughout the infrastructure which in turn makes switches send "reset" packets for server ssh connections (thus disconnecting them). To protect against that we set "bpduguard" setting on port-channel as well as physical ports. Bpduguard command protects from spanning tree changes but we noticed that this command breaks port-channels on the switches and they begin to work through physical interfaces instead of port-channel interfaces (even though the server believes it to still be in port-channel setup). Without bpduguard command port-channels establish correctly on the switch but to prevent spanning tree changes we must keep it on. Is there perhaps a proper way of setting bpduguard on port-channels and their physical ports?

interface Port-channel 1
no ip address
portmode hybrid
switchport
spanning-tree rstp edge-port bpduguard
rate-interval 5
vlt-peer-lag port-channel 1
no shutdown

interface TenGigabitEthernet 1/1
no ip address
spanning-tree rstp edge-port bpduguard
!
port-channel-protocol LACP
  port-channel 1 mode active
no shutdown

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October 20th, 2020 09:00

Hi AndriusLi,

Which OS version are you running on the switches? Which ports are flapping, the VLT ones?

 

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October 21st, 2020 03:00

By port flapping, I meant intentional flipping on/off of ports. We don't have issues with ports turning on/off on their own. The thing is that booting and rebooting causes spanning-tree changes with ports going down and up.

Dell Application Software Version: 9.11(2.0P0)

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October 21st, 2020 10:00

Can you try updating to 9.14?

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December 3rd, 2020 03:00

Turns out there are some kind of firmware issues for VLT on versions prior to 9.14.2.6. Updated to 9.14.2.8 and it is operating as it should.

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