ospf virtual link not coming up

[Martin Kraus]

On Tue, Nov 27, 2012 at 10:27:33PM +0100, Ondrej Zajicek wrote:
> On Sun, Nov 25, 2012 at 02:46:36PM +0100, Martin Kraus wrote:
> > Hi.
> > I'm playing with ospf and got stuck on a virtual link with a cisco router. The
> > cisco virtual link is up and I can see hello packets coming to the linux
> > router but nothing going out. It's connected through area 0.0.0.1. I can see
> > both routers in lsdb. 
> > 
> > debug in bird produces following:
> > 
> > OSPF: Received packet for unknown vlink (ID 192.168.70.1, IP 10.5.1.1)
> 
> This is because vlink iface on linux router is down.
> 
> > bird RID 10.4.7.1:
> > 
> >         area 0.0.0.1 {
> >                 interface "r2" {
> >                         cost 10;
> >                         type pointopoint;
> >                         neighbors {
> >                                 10.4.8.2;
> >                         };
> 
> The config is probably OK. Note that 'neighbors' option is unnecessary
> for ptp link.

hi. 

I managed to get the vlink up. I'm using ptp on a broadcast network to get rid of the DR/BDR
timeout. All the segments are ethernet. I assumed that is a correct way to do it but I might 
be wrong. I'm actually using gns3 to do the simulations but that shouldn't
matter.

bird> s o s all

area 0.0.0.0

    router 192.168.70.1
        distance 20
        vlink 10.4.7.1 metric 20
        xnetwork 192.168.60.1/32 metric 11
        xnetwork 192.168.70.1/32 metric 1
        xnetwork 10.4.8.0/28 metric 20
        xnetwork 10.5.1.0/28 metric 10
        xnetwork 10.5.2.0/28 metric 10
        xrouter 10.4.7.1 metric 20

    router 10.4.7.1
        distance 0
        vlink 192.168.70.1 metric 20
        stubnet 10.4.7.0/28 metric 10
        xnetwork 192.168.60.1/32 metric 11
        xnetwork 192.168.70.1/32 metric 21
        xnetwork 10.4.8.0/28 metric 10
        xnetwork 10.5.1.0/28 metric 20

area 0.0.0.1

    router 192.168.60.1
        distance 10
        router 10.4.7.1 metric 10
        network 10.5.1.0/28 metric 10
        stubnet 192.168.60.1/32 metric 1
        stubnet 10.4.8.0/28 metric 10

    router 192.168.70.1
        distance 20
        network 10.5.1.0/28 metric 10
        stubnet 192.168.70.1/32 metric 1
        xnetwork 10.5.2.0/28 metric 10
        xrouter 10.4.7.1 metric 20

    router 10.4.7.1
        distance 0
        router 192.168.60.1 metric 10
        stubnet 10.4.8.0/28 metric 10
        xnetwork 10.4.7.0/28 metric 10

    network 10.5.1.0/28
        dr 192.168.70.1
        distance 20
        router 192.168.70.1
        router 192.168.60.1

other ASBRs

    router 10.4.7.1
        external 0.0.0.0/0 metric2 10000


10.4.7.1 is running bird. It's connected to 192.168.60.1(R3) and that in turn is
connected to 192.168.70.1(R4).

the vlink is setup between 10.4.8.1 (on RID 10.4.7.1) and 10.5.1.1 (on RID
196.168.70.1)

The way to get the vlink on bird working was to set the ospf between R3 and
R4 to broadcast. Cisco could determine the vlink ip address on the linux box
on the ptp network and when I setup another cisco router in place of 10.4.7.1
I could get the vlink up over the ptp network as well.

How is the peer ip address determined? I don't see it in any of the LSAs. 

thanks
Martin