Direct protocol affects BGP

Fabiano D'Agostino fabiano.dagostino96 at gmail.com
Tue Mar 24 21:53:16 CET 2020


Yes, 'show route', is from Bird. I don't have route-reflector, but just two
routers which have a bgp session. Anyway, yes when direct is disabled, the
bgp session is established.

Il giorno mar 24 mar 2020 alle ore 21:45 Alexander Zubkov <green at qrator.net>
ha scritto:

> "show route" looks a little weird, is it from bird? There are also
> commonly a protocol and metric shown.
> Those are from your route-reflector? Do you have your bgp sessions up
> when direct is disabled?
>
> On Tue, Mar 24, 2020 at 9:33 PM Fabiano D'Agostino
> <fabiano.dagostino96 at gmail.com> wrote:
> >
> > Good evening Alexander,
> >
> > Direct protocol enabled:
> > 'route' command:
> > Destination Gateway Genmask            Flags Metric iface
> > 192.168.1.0      *        255.255.255.0       U       0         enp0s3
> > 192.168.1.0      *        255.255.255.0       U       32       enp0s3
> > 192.168.2.0      *        255.255.255.0       U       0         enp0s8
> > 192.168.2.0      *        255.255.255.0       U        32      enp0s8
> > 192.168.4.0      *        255.255.255.0       U        32      enp0s8
> > 'show route' command:
> > 192.168.1.0/24 enp0s3
> > 192.168.2.0/24  enp0s8 via 192.168.2.22 on enp0s8
> > 192.168.4.0/24 via 192.168.2.22 on enp0s8
> >
> > Direct protocol disabled:
> > 'route' command:
> > Destination Gateway Genmask            Flags Metric iface
> > 192.168.1.0      *        255.255.255.0       U       0         enp0s3
> > 192.168.2.0      *        255.255.255.0       U       0         enp0s8
> > 'show route' command:
> > empty
> >
> > Thanks,
> >
> > Fabiano
> >
> > Il giorno mar 24 mar 2020 alle ore 21:00 Alexander Zubkov <
> green at qrator.net> ha scritto:
> >>
> >> I think it would be easier if you showed your route tables in both
> cases.
> >>
> >> On Tue, Mar 24, 2020 at 8:57 AM Irene Lalioti <irene.lalioti at restena.lu>
> wrote:
> >> >
> >> > Hello guys!
> >> >
> >> > Just because today we encountered again the same issue with direct, I
> am very curious on this:
> >> >
> >> > I totally agree with what you guys explained about the need of the
> direct protocol. Once we set it then reachability works and all is ok.
> >> >
> >> > Our big question is why was it working before the moment it lost the
> BGP session?? In other words: the set up :
> >> >
> >> > RS - BGP session with the ROUTER - and behind the Router we have
> Caches.
> >> >
> >> > Before the router was announcing to the RS(BIRD v2.0.7) the caches
> and that they are reachable by the router. Without any direct.
> >> >
> >> > Until one day we lose the bgp session, and we can ping the caches
> from the RS but not reachable . Once we set it as direct on the bird then
> all is fine.
> >> >
> >> > Question is why was it working before without direct ?? :=)
> >> >
> >> > Many thanks for your time!
> >> >
> >> > Have a great day all!
> >> >
> >> > Irene.
> >> >
> >> > On 23/03/2020 17:07, Fabiano D'Agostino wrote:
> >> >
> >> > Hi Bernd,
> >> > no, the routing "from the kernel" doesn't come via 'learn yes', but
> via RIB, I mean if I do 'route' it shows the directly connected networks.
> The problem is that if I use the Direct protocol, the command 'route' shows
> me two same directly connected networks, one coming from RIB and the other
> one coming from Bird.
> >> > I tried protocol bgp { direct; }, but it doesn't change.
> >> >
> >> > Thanks,
> >> >
> >> > Fabiano
> >> >
> >> > Il giorno lun 23 mar 2020 alle ore 16:15 Bernd Naumann <
> bena at spreadshirt.net> ha scritto:
> >> >>
> >> >> On 23.03.20 16:01, Fabiano D'Agostino wrote:
> >> >> > Hi Benedikt,
> >> >> > I am just learning Bird and I didn't want to use the Direct
> protocol
> >> >> > because using it I have two same routes in the RIB for the directly
> >> >> > connected networks, one coming from the kernel and the second one
> coming
> >> >> > from the direct protocol.
> >> >>
> >> >>
> >> >> Is the routing "from the kernel" coming via `learn yes;`? If you
> have no
> >> >> need to import "alien" routes, you can disable `learn` and just use
> >> >> `direct` and `static` protocol. /* OR if you know that your neighbor
> is
> >> >> directly connected to you can also set 'direct' on the `protocol
> bgp`. */
> >> >>
> >> >> Bernd
> >> >>
> >> >>
> >> >
> >> > --
> >> > Irene Lalioti
> >> > Network Engineer
> >> > Fondation RESTENA
> >> > 2, avenue de l'Université
> >> > L-4365 Esch/Alzette
> >> >
> >> > Tel: +352 424409 1
> >> > Fax: +352 422473
>
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