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There's alot of fear around the possibilities of flapping routes, but alot of real world data seems to show it doesn't happen seem to impact web traffic that of
by anonacct37 9y ago
There's alot of fear around the possibilities of flapping routes, but alot of real world data seems to show it doesn't happen seem to impact web traffic that often.
People often mix and match anycast/Geo DNS and anycast/unicast http.
Some even go a step further and, for video files, anycast to a node that 302s to it's own unicast address.
- scurvy 9y agoIndeed. There are also right ways to setup anycasting and wrong ways. Right way: 1-2 major Tier1 carriers across all of your PoPs with local peering for regional eyeball networks. Wrong way: Using a different set of transit carriers at each location. You really don't want that many AS paths to reach your content from a given location (3-4 is more than enough). What you're really going for with BGP anycasting is that your local ISP has a direct route to the closest PoP via exchange peering, or that the Tier1 path drop you off to the "closest" route. Transit carriers do this for a living, and they're usually quite good at figuring out route weighting inside their own network. Yes, I know Netflix does it differently but they use a lot more smart geo DNS routing than anycasting. Edit: IMHO it's also better to choose a Tier1 with a moderate sized network that values stability and performance over size. So someone like NTT over say Level3.