Bird bfd configuration

[Ondrej Zajicek]

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

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."