[Xorp-users] virtual link

Bruce Simpson bms at incunabulum.net
Fri May 1 09:17:53 PDT 2009


Tomek wrote:
> Hi,
>
> I've got a problem with xorp configuration. 
> Actually in my case situation looks like this:
>
> R3 <-> R5 <-> R4 <-> R6  
>
> where:
>
> R3 is an ABR of area 0 (left side) and area 1 (right side)
> R5 is internal of area 1
> R4 is ABR of area 1(left side) and area 3 (right side)
> R6 internal of area 3 
>
> everything works fine until i want to configure virtual link between R3 and R4
> I added virtual-link section to area 0.0.0.0 in ospf4 section
>   
...

 * Which version of XORP are you using?
 * Which platform are you using XORP on?
>                 area 0.0.0.0 {
>                         virtual-link 192.168.0.40 {
>                                 transit-area: 0.0.0.1
>                         }
>                        ....
> and tried to add virtual-link to R4 without succeed because of error:
> Command failed Virtual link must be in area 0.0.0.0
>
> my question is how to configure virtual link at R4 ?
>   

This could be a problem in vlinks traversing area borders, or more 
likely, a problem with the lookup by router ID.

I'd have to check this code more fully before I could respond in detail 
about that.

The configuration steps you posted look correct, assuming that you are 
configuring XORP up on R3.which is an ABR. But is area 1 a transit area 
or a stub area? An NSSA area is *not* valid for virtual links, they can 
only be configured across transit areas.

More general questions:
Does R3 learn about R4 without the virtual-link config?
If so, which area(s) does R3 learn that R4 is in?
Does R5 see the same topology (neighbours) as R3 and R4?

thanks,
BMS



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