[e2e] It's all my fault

[Vadim Antonov]

On Tue, 15 May 2007, Christian Huitema wrote:

> > To select a path you have to know addresses of points along the path.
> 
> Not really, or at least not always, if the hosts are multi-homed, or if
> the information is present on several different hosts (as in
> bit-torrent). Each pair of source-destination addresses determines a
> path in the network: the source addresses determines the entry point,
> the destination address determines the exit, and the network determines
> the path in between. Hosts don't need to understand the network topology
> to assess which pairs provide the better service.

Yep. But that does not have anything to do with Source Routing. The 
network gateways determine which paths are taken. The hosts determine 
which end-points they're talking with.
 
When hosts are multihomed you sometimes can control the exit point for 
the originated connections... but a cursory look at the existing 
application software shows pretty clearly that only a tiny fraction of it 
actually supports egress interface selection.  And that STILL does not let 
you control the path of the packets - only to choose one of the few paths 
selected for you by the ISPs.

--vadim