detect down bgp sessions and repair them

[majst01]

If a switch is re-installed with a newer version of the switch OS, it sometimes lead to a situation where the BGP Session will never come up again, this looks at the switch side like so:

# net show bgp vrf all summary |grep never
swp21s3                                                4          0       0       0        0    0    0    never      Connect
swp6s1                                                 4          0       0       0        0    0    0    never      Connect

On the worker node a similar output can be inspected.

This situation can be solved without rebooting the worker node by executing:

ethtool --pause <interface where no session is active> rx on|off

It must be either set to on or off, it must only toggle