Hi there,
Hope you networking experts can shed some light on a concern I have please. I am multihoming using 2 ISPs to the internet, due to reasons outside my control, my primary preferred link keeps dropping a number of times a day forcing traffic to my backup and vice-versa when the primary comes back up.
The route calculations by the upstream tier 1s and 2s handle the route calculations but if I do this too many times consuming their resources, is there a penalty/blackmark on my AS? Is this monitored even by the tier1s and 2s?
Thanks.
Regards,
Gus C.
Hope you networking experts can shed some light on a concern I have please. I am multihoming using 2 ISPs to the internet, due to reasons outside my control, my primary preferred link keeps dropping a number of times a day forcing traffic to my backup and vice-versa when the primary comes back up.
Is it feasible to make your backup ISP your primary ISP until your 'real' primary ISP gets the link flapping issues sorted out, or you and your real primary ISP work together to get the issue sorted out?
The route calculations by the upstream tier 1s and 2s handle the route calculations but if I do this too many times consuming their resources, is there a penalty/blackmark on my AS? Is this monitored even by the tier1s and 2s?
Networks can choose to implement some amount of BGP flap damping, however this is generally done at the closest point to the source of the flapping.
This is typically a temporary measure - the damped routes will be restored after a period of stability.
The bigger issue is finding the source of the flapping and getting it fixed.
jms
Generally I don't like to see BGP flap more than 3 times in an hour or two. I've seen some people do some really fast flapping and find themselves isolated from quite a few networks for 30 minutes or so. It really just depends on who out there is doing route dampening and how they configured it. Remember, a single flap from your point of view is possibly multiple flaps from other router viewpoints.
Generally it is not an ASN issue unless you're just horribly bad, but individual networks can have issues with automated mechanisms.
Jack