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40 Posts


February 27th, 2024 14:55

Delay the bring up of orphan ports (non spanned, non-VLT) in OS9 after peer reload/VLTi failure?

In OS10, a mechanism for this already exists: vlt delay-restore orphan-port enable. It allows you to define orphan ports and uses the delay-restore timer to delay the bring up of those ports.

In OS9, there is only port-delay-restore which delays the bring up of all ports after a switch reboot. A peer reload (I think, correct me if I'm wrong) is essentially the same as reboot, so I would assume that all ports would be held down in that case as well. If not, the only mechanism that exists in OS9 to hold down any ports after a peer reload/VLTi failure is delay-restore. That only applies to vlt port-channels from what I understand.

We will be deploying a new MS Failover Cluster with nodes using Switch Embedded Teams. SET only supports switch independent configuration (No LACP), so we can't create VLT port-channels towards them. I am wondering if there will be any negative affects if the bring up of those ports are not delayed during a peer reload/VLTi failure. Is port-delay-restore sufficient, or should we use Uplink Failure Detection...or is there something else?



3.2K Posts

February 27th, 2024 21:45



The delay-restore timer in OS9 when configured under vlt domain is equivalent to the delay-restore VLT timer in OS10 - When the reloaded node joins as a secondary node in the VLT domain or fabric, VLT port-channels are brought up only after delay-restore timer expires. For the duration of delay-store, the VLT port-channels are kept down on the node that rebooted or kept down on the secondary node when VLTi went down. This does not apply to orphan ports.


The delay-restore for orphan ports feature in OS10 extends the support of delay-restore timer for the VLT LAGs to orphan ports. The timer corresponding to the VLT LAG also control the orphan-ports. When delay-restore orphan port is configured, the orphan port is treated just like VLT LAGs during VLT peer reload and VLTi link failure scenarios. This exact functionality is not present in OS9.


The delay-restore feature for non-VLT ports in Dell Networking OS9   delays the bring-up of these ports. By doing so, it allows sufficient time for protocols and features to converge. This setting for non-VLT ports may have effects on the port in the case if the port keeps flapping.


Uplink Failure Detect is recommended for OS9 – has effects on all server facing ports not only orphan ports to make sure that traffic is not blackholed until the uplink is ready to be used.


The UFD is more commonly used in OS9 than the delay-restore for non-VLT ports, and that may be sufficient in your case.

1 Rookie


40 Posts

February 28th, 2024 13:12

@DELL-Charles R​ Thank you!!

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