tcp versus udp

[Sam Wilson]

In article <gtr212$2205$1 at sf1.isc.org>, Danny Mayer <mayer at gis.net> 
wrote:

> Peter Dambier wrote:
> > Hello Martin,
> > 
> > since a major outage at my provider, dtag.de or Deutsche Telecom AG, I have 
> > trouble
> > with f.root-servers.net. Sometimes "dig ... +vc" does help me to see 
> > f.root-servers.net.
> > 
> > The real problem is anycast. With udp it behaves different than with tcp.
> 
> That's nonsense. anycast is invisible to this. anycast doesn't care if
> it's udp or tcp, it only deals with the routing tables to determine
> where to send the request packet.

It's not quite nonsense, only very nearly.  One can imagine a corner 
case where a router has equal cost paths to more than one anycast 
instance and that same router is set up to do per-packet load balancing, 
then it might not be possible to set up a TCP connection to that anycast 
address through that router.  This is likely to be a rare occurrence.

Sam