6bone Registry & bidirectional tunnels

[Alain Durand]

On Sep 23,  1:47pm, davidk@ISI.EDU wrote:
> Subject: Re: 6bone Registry
>
> > True, and if we do include the handle along with the addresses of the
> > endpoints, that would clear up which was which. We then could eliminate the
> > 'src' and 'dst' keywords and end up with something like:
> >
> > tunnel: IPv6 in IPv4 129.99.236.71 NAS to 192.xxx.xxx.xxx Cisco
> >
> > The insertion of the "to" keywoard could replace "src" & "dst" while still
> > delimiting the string somewhat.
>
> I like this idea. You might want to substitute 'to' by <-> for
> bidirectional tunnels and ->/<- for unidirectional tunnels (this might be
> an academic possibility, but who knows ?). This also avoids alpha-numeric
> characters and thus makes it easier for the software (and may be even for
> humans) to parse the tunnel line in the right parts.

humm... just that from what I understand of tunnels (at least in the
implementations I'm working with) they are essentially asymetric.
That is, you specify where your packets are going, not where they
come from. So a tunnel is only bidirectional if both sides configure it
in the same way.

Maybe we should emphasize that this SHOULD always be the rule.
I have already experiment misconfigured sites with asymetric tunnels,
packets do not take the same path on their way back, and sometime we get
very weird results and I feel it's more difficult to debug.

	- Alain.