BGP and anycast

Tue Jan 30 18:19:40 UTC 2001

A good point.  This document assumes a DNS context, and thus that the
UDP request and response are self-contained.  I will attempt to make
it more clear in the text, but this is exactly the sort of caution I
was trying to get at: do not assume that a hack that works in some
circumstances for the DNS will work for other services.
			regards,
				Ted Hardie


> 
> On Tue, 30 Jan 2001 hardie at equinix.com wrote:
> 
> >   One potential problem with using shared unicast addresses is that
> >   routers forwarding traffic to them may have more than one available
> >   route, and those routes may, in fact, reach different instances of
> >   the shared unicast address.  Because UDP is self-contained, UDP
> >   traffic from a single source reaching different instances presents
> >   no problem.  TCP traffic, in contrast, may fail or present
> 
> That should be a little more precise.
> 
> TCP packets can not (for all practical purposes when dealing with "normal"
> clients) be self contained.
> 
> UDP packets are self contained, from the network view.
> 
> But that does not mean that a particular protocol implemented on top of
> UDP will necessarily still be self contained, merely that it is possible
> for it to be.
>