Sometimes you don't have as much control over a client (many non-HTTP TCP applications). A middle ground is to use anycast for authoritative DNS and return a se

Sometimes you don't have as much control over a client (many non-HTTP TCP applications). A middle ground is to use anycast for authoritative DNS and return a set of records for unicast IPs local to that POP. You get the benefits of anycast and the stickiness of unicast. It's a short jump to overriding decisions to correct certain clients, or to shed traffic from servers or POPs.