Implementations/suggestions for Multihoming IPv6 for DSL sites

Cameron Byrne cb.list6 at
Mon Apr 11 17:09:20 UTC 2011

On Mon, Apr 11, 2011 at 9:19 AM, Jeff Wheeler <jsw at> wrote:
> On Mon, Apr 11, 2011 at 11:26 AM, Owen DeLong <owen at> wrote:
>> I'd agree with you if it weren't for the fact I keep thinking I just about understand LISP and then get told
>> that my understanding is incorrect (repeatedly).
> I agree it is not simple.
> At a conceptual level, we can think of existing multi-homing practices
> as falling into one of three broad categories:
> 1) more state in DFZ -- end-site injects a route into BGP
> 2) triangular routing -- tunnel/circuits/etc to one or more upstream
> routers while not injecting anything to DFZ
> 3) added work/complexity on end-host -- SCTP and friends
> LISP is a compromise of all these things, except #3 happens on a
> router which does tunneling, not the end-host.  Whether you think it's
> "the best of both [three?] worlds," or the worst of them, is up to
> you.
> I personally believe LISP is a horrible idea that will have trouble


> scaling up, because a large table of LISP mappings is not any easier
> to store in FIB than a larger DFZ.  The "solution" the LISP folks
> think works for this is a side-chain mapping service which the router
> can query to setup encapsulation next-hops on-demand, which means if
> your FIB isn't big enough to hold every mapping entry, you are
> essentially doing flow-based routing, but with "flows" defined as
> being toward a remotely-defined end-site rather than toward an
> individual IP address (so not quite as bad as "flow-based routing" of
> the past, but still bad.)
> Maybe I also don't understand LISP and need to RTFM more, but my
> current understanding is that it is a dead-end technology without the
> ability to dramatically scale up the number of multi-homed end-sites
> in a cheaper manner than what is done today with BGP.
> I think we would be better off with more work on things like SCTP.

+1 SCTP and IPv6, then ILNP.

> --
> Jeff S Wheeler <jsw at>
> Sr Network Operator  /  Innovative Network Concepts

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