In message <20161229162721.34651.qmail@xxxxxxx>, "John Levine" writes:
> > ... However, my impression is that we
> >are seeing increasing ISP concentration (except, maybe, close to
> >the edges of the network, where it makes little difference) and
> >less of that traditional type of multihoming.
>
> There's tons of multihoming. Every medium sized or larger business
> wants multiple upstreams for reliability. They typically get a chunk
> of PA IPv4 addresses from each upstream.
>
> This is a big reason why providers don't implement BCP38. A customer
> has one block of addresses from provider A and another from provider
> B. In general each provider only knows about its own address block,
> but the traffic comes from both blocks, and the customers get rather
> annoyed if a provider doesn't accept their traffic. ("If you don't
> want our $20K/month, we're sure we can find someone else who does.")
> Trying to keep track of what customer has what block of someone else's
> address space is hopeless, so they just turn off the filters for the
> multihomed customers.
BCP38 should be automatable at the edge even with multihoming. We
do have the technology to provide each customer with a CERT that
says they have been assigned this block of addresses. This CERT
can be presented to the other providers along with a signed request
to say please accept this range of addresses over this interface.
This doesn't have to be done using BGP. Machines can process these
without a human being involved. It just requires willingness to
do this.
Embrace the technology.
> This is of course a place where v6 wins, since the customer can
> get their own block of PI space, but then there's all those other
> v6 deployment problems.
>
> R's,
> John
>
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx