Re: If IPv6 multihomed sites were cars

[Iljitsch van Beijnum <iljitsch@muada.com>]

On Mon, 10 Sep 2001, Michael Richardson wrote:

> >>>>> "Michel" == Michel Py <py_michel@yahoo.com> writes:

>     Michel> On the same road, you can see trucks, sports cars,
>     Michel> Mercedes', and Yugos.

>     Michel> This specialization applies to almost technology item.

>   You seem to be saying that different people will get different
> results using the same mechanisms.  If this is your point, then we agree.
> But, you have argued for different mechanisms before.

>   In each category you describe several variations on the same theme which
> result in differing qualities in the return on investment.

>   But, in each category there are some essential principles which are
> the same. airplanes have wings and means of propulsion, cars and trucks have
> wheels, brakes, steering and propulsion, and PDAs and Celerons have I/O, CPU
> and storage.

I think what we're doing here compares to building roads in the car
analogy. Unfortunately, the differences in IP are somewhat bigger than an
order of magnitude in size or the quality of the seats. The slowest
devices on the network are five orders of magnitude slower than the
fastest. If we compare DS3 to the Mercedes and an ADSL user to a
pedestrian, there are also snails (cell phone modem) and vehicles going
mach 4 (Gigabit Ethernet) on the road.

I feel we shouldn't spend too much time figuring out the perfect
multihoming solution for a certain group of users, when each form of
multihoming we've discussed so far has serious drawbacks and none of them
is likely to be perfect anyway. And users have the annoying habit to use
the technology in the way it best suits them, rather than in the way the
designers intended.

That being said, there are already multihoming solutions on the table that
cater to the needs of four groups.

ISPs can still do what they do now by getting a TLA address block and
using BGP.

Enterprises and smaller ISPs can take an address block from an upstream
ISP and announce it to several ISPs over BGP. Since these announcements
will very likely be filtered in the DFZ, there is no guaranteed
network-wide redundancy, but when done carefully this could still work
very well.

Small to medium sized organizations or departments of larger organizations
can use proxy address rewriting boxes to do multi-address multihoming
processing for a large number of hosts and/or servers, if we create a
protocol that allows this.

Individual hosts can do their own MAMH processing, similar to mobile IP or
SCTP.

So there is really no problem, as long as we can make something good for
multi-address multihoming and this is implemented widely enough to be
useful.