What is the best / least abusive way to determine Internet connection state at a high rate (once a second or better)?
I can just ping a well-known IP (like google's DNS - 8.8.8.8 or similar), but it seems to me that continually generating traffic to such public servers could be interpreted as abusive, particularly if it's at a high data rate.
Is there a better way, or any servers that explicitly allow continuous pinging, or a similar tool?
Personally, I'd ping a router belonging to your ISP upstream of you - but that only works for certain definitions of "internet connection". If it's sufficient to just confirm your connection to your ISP, then do that.
Oherwise, I'd still say hit routers instead of servers. It may only be my perception, but pinging a router seems less "abusive" than a server. But if there's numerous nodes all confirming their connectivity once per second, then I wouldn't fault a carrier for filing an abuse report with your ISP - one ping a second is just fine, hundreds or thousands will probably get noticed.