Bird bfd configuration

[LIU Chris]

Classified as: {Hitachi Rail – Public}

Hi Zajicek,

It seems this nice configuration doesn’t work, have to set bfd instance

Below configuration bfd doesn’t work

protocol bgp BGP_INSTANCE_1 {
        local 10.64.0.2 as 65002;
        neighbor 10.64.0.50 as 65050;
        ipv4 {
                import filter export2Kernel;
                export filter export2BgpPeer;
                preference 200;
        };
        hold time 3;
        bfd {
                              min rx interval 1 s;
                             min tx interval 1 s;
                             idle tx interval 3000 ms;
                              multiplier 3;
             };
}
protocol bgp BGP_INSTANCE_2 {
        local 192.168.0.50 as 65002;
        neighbor 192.168.0.51 as 65001;
        ipv4 {
                import filter export2Kernel;
                export filter export2BgpPeer;
                preference 100;
        };
        hold time 3;
        bfd {
                            min rx interval 1 s;
                           min tx interval 1 s;
                           idle tx interval 3000 ms;
                           multiplier 3;
               };
}
protocol bfd {
}

below configuration works:
protocol bgp BGP_PA_CTI_LTE {
        local 10.64.0.2 as 65002;
        neighbor 10.64.0.50 as 65050;
        ipv4 {
                import filter export2Kernel;
                export filter export2BgpPeer;
                preference 200;
        };

        hold time 3;
    bfd on;
}

protocol bgp BGP_PA_CTI_FM {
        local 192.168.0.50 as 65002;
        neighbor 192.168.0.51 as 65001;

        ipv4 {
                import filter export2Kernel;
                export filter export2BgpPeer;
                preference 100;
        };

        hold time 3;
    bfd on;
}

protocol bfd {
    interface "*" {
            min rx interval 1 s;
            min tx interval 1 s;
            idle tx interval 3000 ms;
            multiplier 3;
    };
        neighbor 10.64.0.50 local 10.64.0.2;
        neighbor 192.168.0.51 local 192.168.0.50;
}


With Best Regards,
Chris LIU


{Hitachi Rail – Public}
-----Original Message-----
From: Bird-users <bird-users-bounces at network.cz> On Behalf Of LIU Chris via Bird-users
Sent: Monday, February 13, 2023 10:50 AM
To: Ondrej Zajicek <santiago at crfreenet.org>
Cc: bird-users at network.cz
Subject: RE: Bird bfd configuration

Oh, wonderful, nice configuration. Will try

-----Original Message-----
From: Ondrej Zajicek <santiago at crfreenet.org>
Sent: Monday, February 13, 2023 10:45 AM
To: LIU Chris <chris-zq.liu at urbanandmainlines.com>
Cc: bird-users at network.cz
Subject: Re: Bird bfd configuration

On Mon, Feb 13, 2023 at 02:56:56PM +0000, LIU Chris wrote:
> Hi Zajicek,
>
> Many thanks for your reply.
> No any problem to set just one BFD instance.  In my case, I have multiple BGP instances,  I set bfd on inside each BGP instance.
> If just one bfd instance,  how do bird correlate with BGP instances ?

The BFD instance knows which BGP instance requested that peer, so it notified appropriate BGP instance if something happens with that peer.

> And also, if want to set different min/max Rx interval value for each BGP session in BFD instance configuration, how to distinguish them ?

If they are on different ifaces (like in your example), you can have multiple interface statements in one BFD instance.

But in general, you can specify BFD parameters also directly in BGP protocol as options of 'bfd' switch:

https://bird.network.cz/?get_doc&v=20&f=bird-6.html#bgp-bfd

protocol bfd {
}

protocol bgp {
  ...
  bfd {
    min rx interval 1000000 us;
    min tx interval 1000000 us;
  };
}


--
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
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