[Xorp-users] wanted: OSPF metrics per neighbor. can vif help?

Nick Feamster feamster@lcs.mit.edu
Thu, 10 Nov 2005 11:39:55 -0500


On Thu, Nov 10, 2005 at 05:15:27PM +0100, Kristian Larsson wrote:
> On Thu, Nov 10, 2005 at 01:48:04AM -0500, Nick Feamster wrote:
> > On Thu, Nov 10, 2005 at 06:25:03AM +0100, Kristian Larsson wrote:
> > > > I understand what the RFC says, and sticking to standards seems like a
> > > > good idea in general.  If I could create multiple virtual interfaces
> > > > (vifs) on top of a single phyiscal interface (e.g., one vif per
> > > > neighbor) and subsequently set the interface cost per vif, then would
> > > > that not comply with the standard and give me the functionality we
> > > > want/need?
> > > Even if you could create several interfaces it
> > > would not do you much good. How would you separate
> > > the traffic between the interfaces?
> > > I beleive it to be very difficult.
> > 
> > Easy: each vif would have a separate IP address on which traffic could
> > be demuxed.
> If you want separate ip adresses in different this
> should be possible to solve via alias interface.
> On linux:
> ifconfig eth0 1.1.1.1 netmask 255.255.255.0
> ifconfig eth0:1 2.2.2.2 netmask 255.255.255.0
> though if you wan't them all in the same subnet it
> would be hard. This was what I assumed but I
> suppose I'm wrong.

Yes, IP aliasing is the functionality I was referring to; I want to know
how to do this in *XORP*.  I don't want to do this in the kernel
because:

1. This is not possible on planetlab.
2. Even if it were, I want to configure vifs that correspond to those
   aliases.  This does not seem possible since the vif name would match the
   physical interface name.

Back to my original question and what I am trying to achieve:

Given one physical interface, can I configure multiple vifs and set an
interface-cost per vif?  I don't care if all vifs or what have you have
the same IP address, even, as long as I can set different OSPF interface
costs for each one.

-Nick