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Re: iBGP next hop and multi-access media

  • From: Christopher L. Morrow
  • Date: Mon Oct 07 00:55:17 2002


On Mon, 7 Oct 2002, Ralph Doncaster wrote:

>
> My understanding is the route is valid as long as the interface is
> up; just like adding a secondary IP on the interface.
>

If you are going through all this trouble, why not just secondary the
interface, while you at it run HSRP or VRRP and provide some HA-ness for
your LAN?

> Ralph Doncaster
> principal, IStop.com
>
> On Mon, 7 Oct 2002, Alex Rubenstein wrote:
>
> >
> > Aha.
> >
> > So, if you route to a ethernet interface, it will try to arp for that
> > address on that subnet, even without having a local address on the same
> > subnet?
> >
> > This seems to me to be something you don't want to do.
> >
> > Is the entire route valid as long as the router can ARP for one of the
> > addresses in the routed subnet?
> >
> >
> >
> > On Mon, 7 Oct 2002, Ralph Doncaster wrote:
> >
> > > On Mon, 7 Oct 2002, Alex Rubenstein wrote:
> > >
> > > > I've been doing ip route statements going on 8 years now, and I can't
> > > > imagine why ever -- and how it would even work -- you'd want to ip route a
> > > > netblock with a next hop of a multi-access brandcast media. As in, the
> > > > next hop is still truly undetermined.
> > > >
> > > > I guess I don't know this because I've never tried it. But, how does the
> > > > router determine where to send the packets for a route statement as
> > > > specified above (ip route a.b.c.d e.f.g.h f0/0) ?
> > >
> > > When you setup a secondary ip on an interface
> > >  int fa0/0
> > >    ip address a.b.c.d e.f.g.h secondary
> > >
> > > How does it determine where to send the packets?  ARP.
> > > Which is the same as adding the route described above.
> > >
> > > -Ralph
> > >
> >
> > -- Alex Rubenstein, AR97, K2AHR, [email protected], latency, Al Reuben --
> > --    Net Access Corporation, 800-NET-ME-36, http://www.nac.net   --
> >
> >
> >
>