Bird bfd configuration

[LIU Chris]

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

Chris.


-----Original Message-----
From: Ondrej Zajicek <santiago at crfreenet.org>
Sent: Saturday, February 11, 2023 10:58 AM
To: LIU Chris <chris-zq.liu at urbanandmainlines.com>
Cc: bird-users at network.cz
Subject: Re: Bird bfd configuration

On Fri, Feb 10, 2023 at 03:58:04PM +0000, LIU Chris via Bird-users wrote:
> Anyone comment this issue ?
>
> From: Bird-users <bird-users-bounces at network.cz> On Behalf Of LIU
> Chris via Bird-users
> Sent: Tuesday, January 24, 2023 4:01 PM
> To: bird-users at network.cz
> Subject: RE: Bird bfd configuration
>
> Hello,
>
> I am trying to configure BFD protocol.  If configure 2 instances with below, it doesn't work. So I have to configure one instance, and put all the neighbors list to it.
> Is it possible to configure separate instance ?

Hi

Generally, multiple BFD instances are not that useful, as BFD sessions are assigned to the first one that is acceptable, and unless the BFD instance is limited to specific VRF, address family, direct/multihop mode, it accepts all sessions. Note that in contrast to other protocols, you do not need to specify interfaces, all interfaces are allowed by default. If you specify interfaces, it is just for changing per-iface values. So even if you specify just 'interface "eth2"', it will accept BFD sessions for all interfaces.

Explicit neighbor statements allow you to define BFD session requests manually in addition to automatic session requests from OSPF, BGP and other protocols. But these are processed in the same way - put to the pool of BFD session requests and then assigned to a matching BFD instance.


> The below doesn't work
> protocol bfd Test1 {
>     interface "eth2" {
>         min rx interval 1000000 us;
>         min tx interval 1000000 us;
>         idle tx interval 3000000 us;
>         multiplier 3;
>     };
>     neighbor X1.Y1.Z1.A1 local X1.Y1.Z1.B1; }
>
> protocol bfd Test2 {
>     interface "eth0" {
>         min rx interval 1000000 us;
>         min tx interval 1000000 us;
>         idle tx interval 3000000 us;
>         multiplier 3;
>     };
>     neighbor X2.Y2.Z2.A2 local X2.Y2.Z2.B2; }
>
> Below it is working,
> protocol bfd Test {
>     interface "eth*" {
>         min rx interval 1000000 us;
>         min tx interval 1000000 us;
>         idle tx interval 3000000 us;
>         multiplier 3;
>     };
>     neighbor X1.Y1.Z1.A1 local X1.Y1.Z1.B1;
>     neighbor X2.Y2.Z2.A2 local X2.Y2.Z2.B2; }
>
>
> With best regards,
>
> Chris

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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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