> On Wed, 2003-01-29 at 01:28, [EMAIL PROTECTED] wrote:
> > Well you don't actually want it lifted. You don't want a
> > anycast address being used to *initiate* a transaction.
>
> Why not?
Because the reply traffic is *not* guaranteed to go back
to the same instance. The whole point of this thread is
how to make the traffic go back to the correct instance.
> > You do however want to be able to *reply* using the anycast
> > address. For UDP this is will need to be enforced at the
> > application layer, perhaps with an setsockopt so that the
> > application can inform the stack that it knows that this
> > is *potentially* a anycast addresss. For TCP this can be
> > enforced lower down the stack.
> >
> > e.g.
> >
> > bind(fd, <anycast>);
> > connect(fd, <unicast>);
> >
> > should fail but
> > int yes = 1;
> > bind(fd, <anycast>);
> > setsockopt(fd, ANYCASTSEND, &yes, sizeof(yes));
> > sendto(fd, <unicast>);
>
> I don't think a socket option is needed. If an application binds
> explicitly to anything other than :: it's only fair to assume that it
> knows what it's doing.
It's not a fair assumption that it knows that it is a anycast
address. Every existing application written today that allow
selection of source address fails your test that it know what
it is doing w.r.t. anycast addresses.
> Automatic source address selection should skip anycast addresses, of
> course.
>
> MikaL
>
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