[rrg] Fundamental objections to a host-based scalable routing solution

[Christian Vogt]

Luigi -

> my only point was that using host probing does not allow you to see
> which link is down, since your traffic can go through different LOCs
> depending on the direction.

Given that a pair of communicating hosts could use four locators, a
source locator and a destination locator per each direction:  Why do you
think the hosts couldn't acquire the same information as a set of
routers located on the border links of the two networks involved?

In fact, I would again argue that the host-based approach is more
powerful:  The hosts have more information available than the routers,
because the hosts have visibility of the full end-to-end paths, whereas
the routers do not.

> I agree in general with what you said, except that I do not think that
> probing in the network is harder than probing in the hosts, you just
> have  a different viewpoint.

Then we disagree.  I do maintain that probing in the network is
potentially harder than probing in hosts.  It's not because of the
viewpoint being different.  It's because of the need for coordination
between multiple viewpoints in network-based probing.

- Christian