Cisco IOS - Race condition between NSO commit and out-of-band change?

[ken.mcnamara1]

Is it possible for a manual change to be made while NSO is committing to a Cisco IOS router?

That is, once NSO has begun a commit, decided that it is 'in-sync' with the router - in between that time and finish of the commit - could a manual change be made to the router (possibly interfering with that change)?

I know this is milliseconds - but I have a client who insists that I ask the question.

Thank you.

KenMc

[rogaglia]

Hi,

I think this is more of a device question than an NSO question. You should contact your Cisco IOS specialist and ask how the device would react when:

- For CLI NED: two CLI sessions are carried out at the same time

- For NETCONF NED: when a commit order is sent and a CLI user is configuring the router at the same time.

For the CLI NED, NSO will only check the synchronization at the beginning of the transaction. Afterwards, if the device does not complain about the commands it is entering, it will take the configuration as good.

Roque

[KJ Rossavik]

And that can be followed by a check-sync, if you are concerned about such race conditions, right? So NSO has the facility to mitigate for lacking device capability.

So what you are describing is illustrating why you would want the network devices to be transactional. If the devices are not transactional, then there is only so much NSO can do.

Cheers,

KJ.