That's a nice site with some interesting graphs. They are a bit higher level than the simplest level of surveillance systems so I wouldn't start at an inappropriately higher level to see if there even is a problem. One lower level simple technique to determine or isolate if a problem even exists is to monitor TCP port 179 traffic rate (aka BGP) between your BGP speakers and your peers / customers. If the routers have nothing to talk about between each other, then there IS nothing to talk about, at least WRT routing problems. Or if one of "my" routers was having an intense discussion with another router, I knew something was up in that general direction. And it can be basically completely passive and completely isolated from the routing systems, which is cool. Just sniff -n- graph TCP 179 bandwidth over time. You'd like to see a nice horizontal low line of keepalives. Reboots or restarts make a nasty spike, never got much agreement but log-y-axis is probably for the best.

Obviously this only finds routing level problems. We can send a /17 to you just fine, but if you're having an IGP problem and sending every byte of it to null, well, from the BGP perspective that's just fine. Much as if you insist on sending us RFC1918 traffic we'll drop that route and traffic for you just fine, just like we had to eat your 0/0 route you're trying to get us to advertise to the entire internet. I think my head still has a flat spot from hitting it on the desk arguing with people.

Its been a decade since I did that stuff professionally at a regional ISP and I really don't miss it. Not much, anyway.