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Re: multihoming, was IPv10

2016-12-29 19:57:43

In message <20161229162721(_dot_)34651(_dot_)qmail(_at_)ary(_dot_)lan>, "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(_at_)isc(_dot_)org

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