is-is set-overload-bit on-startup wait-for-bgp solution

[DanPartelly]

In addition to the discussion fragments in #2544, which , I realize now, was a bad place to discuss this issue.

Ill let this open for a day or two, then close it, hoping it will much more easily searchable here then in a PR.

So, before anyone wastes time on this, the solution, at least for Cisco devices, is:

The only way this will work is if the router reads it's configuration it;s configuration from NVRAM. It seems that there are checks in place that if BGP process is not running, ISIS will never set the overload bit, and that the checks are done very early once the processes has been spawned. So even with all race conditions solved in netlab, you cant study this IS-IS behavior that way.

The solution is to use containerlab, load the configs, write to NVRAM, and reboot the lab. It is not enough to specify the text files as boot configs. Then you can see it working.

[ipspace]

Assuming the requirement is to load the config in one go, you could also build the config, save it, modify it as needed, and then restart the lab with netlab up --reload folder

[DanPartelly]

Assuming the requirement is to load the config in one go, you could also build the config, save it, modify it as needed, and then restart the lab with netlab up --reload folder

Ive tried that. No go. Really NVRAM was the only thing which worked.