Re: multihoming, was IPv10

["John R Levine" <[e-mail]>]

> I said and meant "traditional type of
> multihoming" and, more important in the previous sentence, "many
> hosts and sites that are multihomed in the traditional sense of
> advertising one set of endpoint addresses to the network and
> letting the routing system sort things out".   That is, very
> specifically, one address per host, advertised to multiple ISPs/
> networks/ paths and not "a chunk of PA IPv4 addresses from each
> upstream".

But it's the same thing -- the customer numbers some of their network with 
PA addresses from one provider and part of it with PA addresses from the 
other.  Then the customer sends out traffic from both address blocks to 
both interfaces, and the upstreams can't tell whether an unknown address 
is a legit one from another provider or a malicious spoof.

I'm pretty sure this is right, having talked to ISPs about it in the 
context of why BCP38 is harder than you'd think.

R's,
John