mailing list archives
Re: Implementations/suggestions for Multihoming IPv6 for DSL sites
From: Owen DeLong <owen () delong com>
Date: Mon, 18 Apr 2011 13:09:11 -0700
On Apr 18, 2011, at 12:18 PM, Jeff Wheeler wrote:
2011/4/18 Lukasz Bromirski <lukasz () bromirski net>:
LISP scales better, because with introduction of *location*
prefix, you're at the same time (or ideally you would)
withdraw the original aggregate prefix. And as no matter how
you count it, the number of *locations* will be somewhat
limited vs number of *PI* address spaces that everyone wants
I strongly disagree with the assumption that the number of
locations/sites would remain static. This is the basic issue that
many folks gloss over: dramatically decreasing the barrier-to-entry
for multi-homing or provider-independent addressing will, without
question, dramatically increase the number of multi-homed or
Done properly, a multi-homed end-site does not need to have
its own locator ID, but, could, instead, use the locator IDs of
all directly proximate Transit ASNs.
I don't know if LISP particularly facilitates this, but, I think it
would be possible generically in a Locator/ID based system.
LISP "solves" this problem by using the router's FIB as a
macro-flow-cache. That's good except that a site with a large number
of outgoing macro-flows (either because it's a busy site, responding
to an external DoS attack, or actually originating a DoS attack from a
compromised host) will cripple that site's ITR.
The closer you move the ITRs to the edge, the less of an issue this becomes.