I have just upgraded an x86 machine from 3.23 to 3.30 then 4.11 Now all the BGP peers randomly drop at intervals from a few minutes up to half an hour - the log file simply sayes

route bgp error HoldTimer Epired
route bpp error RemoteAddress=x.x.x.x

All hold timers on this machine and it's pears are set to 180
I have tried changing the TTL values 1-255 and default

Does anyone know what may have changed in the upgrade that has caused this error to appear

Thanks in advance, Kind Regards, Murray Southwell

you are probably having packet loss or tcp connection problems. the hold timer expires when there is no bgp session established for 180 seconds. Watch the bgp peer status before this happens and see if its actually disconnected at that time. Maybe you can check connectivity between the two end points and make sure there isnt any packet loss.

I have checked for packet loss as several of the connections traverse leased fibre runs, but could not see any issues.

One of the routers it is dropping BGP sessions to is in the same rack and plugged into the same switch, so I am confident it is not a packet loss issue

See if there are supouts or autosupouts on any of the routers.

Also, if you're using OSPF have you noticed if your OSPF sessions are dropping or resetting? (check the adjacency time in the ospf neighbors).