What would be your recommendation to speed up dual-homed Internet BGP convergence and minimize the effect of ISP flapping? The usual stuff is in place, such as AS path prepend and RFC1998 ISP community. The convergence time takes about as little as 5 min to as much as 10 min.
It’s about 5 minutes from losing access to access being restored, during which we’re waiting for Internet routing convergence when one of the BGP peering is down. We enabled ping on the ingress Citrix rule – that’s how we measure whether the routing has been restored and ping starts to respond.
Our ISPs (Zayo/Cogent) all have looking-glass sites. I didn’t think about using them because I thought the issue would depend on the intermediary ISP. I have been using route-views.routeviews.org, but it shows prefixes to one ISP only.
We’ve had an issue with our ISP and its upstream peer in that the upstream peer always prefers (LP). What the intermediary ISP does is out of our hands. We have since moved away to another ISP, but I feel that BGP alone is insufficient to have a better than good high availability solution. I would personally accept and live with a 5-minute outage, but the client wouldn’t. I was wondering whether I missed any latest config knob or ISP feature that I’m not aware of.