Re: [v6ops] PI [ULA draft revision #2 Regarding isolated networks]

[Gert Doering <[e-mail]>]

Hi,

On Mon, Jun 02, 2014 at 08:10:33AM -0700, joel jaeggli wrote:
> > Well.  It might not have been your intention, but what you said is very
> > clear "we're not going to make multihoming in the homenet case work".
> 
> No sorry I did not. What I said is that I believe you're pushing an
> expectation of a certain amount of complexity onto hosts in the
> interests of measurement and detection of topological corner cases. some
> hosts might choose to do that in the interest of improved connectivity,
> the expectation that they all should is onerous, you be should have an
> expection that devices and applications will work in the absence of HE.
> 
> having a router invalidate itself as a nexthop because it has detected
> that it's paritioned from a provider or the internet seems like an
> incredibly basic concession that you'd want to have happen even were
> everything HE enabled.

You seem to be using a different Internet than I do, which seem to consist
of "the only way things can break is if my CPE loses contact to it's ISP,
which is always easily detectable, but as soon as the packet reaches the
ISP, it will be 100 percent reliably transported and answered, all the
time".

My Internet, unfortunately, seems to have less boolean cases where
packets just disappear when being sent into certain directions, without
even adjacent devices noticing, much less "devices 10 hops away".

> > In the case
> > 
> >     host --> router --> ISP A ---->  ISP C --------+
> > 	       +------> ISP B ---->  ISP D ------> ISP E --> target
> > 
> > where "host" has source addresses A and B, and there is a problem at 
> > ISP *C*, preventing connectivity via A->C->, how exactly is the homenet
> > router "router" supposed to *know* that, or even solve it?
> 
> It doesn't.

Thanks for acknowledging that.

> > Assuming "as long as connectivity to ISP A is there, the whole Internet
> > will be reachable via ISP A" is completely ignoring reality.  Blackhole
> > issues happen (where even BGP to the customer router won't help you)...
> 
> yes, bgp multihoming doesn't solve it either. that has not rendered it
> unsuitable for use.

BGP multihoming has it's uses, but I think all but Owen agree that it's
not going to solve the "billions of leaf networks without IT knowledge"
case.

Multi-Address multihoming has the potential to be a radical improvement
for "leaf networks without IT knowledge".  

Especially for cases that BGP based multihoming will not handle well today, 
like "black hole problems due to people's MPLS stuff running amock", 
"stateful firewalls in the packet path that do not handle asymmetric 
traffic well", "selection of the ISP used by the user, not by the CPE 
router", etc.

It's certainly not a replacement for BGP based multihoming for "networks
with lots of servers and qualified IT staff".  Just to avoid that particular
avenue of ratholing.


> > (IETF is complaining about lack of operator input.  Here is operator input.
> > Don't ignore it, otherwise operators get bored and find solutions outside
> > IETF space, like, with NAT)

Maybe I should include this in of my signature when writing to IETF lists...

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

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