North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Content Delivery Networks
On Aug 7, 2007, at 10:05 AM, Michal Krsek wrote: 5) User redirection This has been discussed. Operational experience posted here by Owen shows < 10% of users are "far" from their recursive NS. You are the tiny minority. (Don't feel bad, so am I. :) Most "users" either use the NS handed out by their local DHCP server, or they are VPN'ing anyway. 2) DNS TTL makes realtime traffic management inpossible. Remember you may not distribute network traffic, but sometimes also server load. If one server/POP fails or is overloaded, you need to redirect users to another one in realtime. Define "real time"? To do it in 1 second or less is nigh impossible. But I challenge you to fail anything over in 1 second when IP communication with end users not on your LAN is involved. I've seen TTLs as low as 20s, giving you a mean fail-over time of 10 seconds. That's more than fast enough for most applications these days. -- TTFN, patrick
|