[Xorp-users] BGP crash

[Arsi Antila]

I'll try to get more information about the situation where the crash
happens. My understanding is that it is only the BGP process which dies,
and it happens when the winning route seen by XORP changes, and the new
winning route is on the same interface as the old winning route.

I would guess that BGP had peering configured using the local IP
addresses of the three ethernets. 


Regards,
Arsi


On Mon, Dec 03, 2007 at 05:43:49PM +0000, Mark Handley wrote:
> Xorp should not crash; I don't think this is a known issue.  Can you
> clarify - which Xorp process crashes?  The subject implies BGP, but I
> just want to be sure.
> 
> Also I'm not clear on the scenario - BGP doesn't advertise ASs to
> interfaces - it advertises them via BGP connections which are only
> loosely connected to interfaces (if you choose an interface IP address
> for the connection endpoint).  Do you mean the BGP has peering
> configured using the local IP addresses of the three ethernets in your
> scenario?
> 
> Which AS is the router that crashes in?
> 
> Your text says 5 routers, but I'm not sure where the 5th one is - the
> minimum needed to implement something like you describe is 4 (One each
> for AS1, AS2, AS3 and the router that crashes).  Where's the 5th one?
> 
> Also could you send the policy config you used to prevent route redistribution?
> 
> If we understood the scenario, we can build a test suite to tickle
> this problem, but right now I don't really know how to do this.
> 
>  - Mark
> 
> On Dec 3, 2007 10:21 AM, Arsi Antila <bbb999 at zerodistance.fi> wrote:
> > Is the following a known problem in XORP?
> >
> > Note: this was shown to me by someone else. I didn't test this myself,
> > so some of the details may be incorrect.
> >
> > XORP crashes when the same set of BGP routes is advertised from two
> > different routers connected to the same interface and the winning route
> > changes. Tested with VLANs, if-aliases and plain interfaces. Results do
> > not vary.
> >
> >
> > For example, configuration of the network is as follows:
> >
> > - device under test (Linux/Debian, XORP) and five simulated routers
> >
> > - AS 1 is advertised to ports eth1 and eth2
> >
> > - AS 2 is advertised to ports eth1 and eth2
> >
> > - AS 3 is advertised to port eth3
> >
> > - Policy rules so that AS 2 routes are not advertised to AS 1
> >
> > BGP process dies when one of the routers in AS 2 goes down and then up
> > so that the primary route in AS 2 changes.
> >
> >
> > Regards,
> > A.A.
> >
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> >