On 2/25/25 01:02, Ondrej Zajicek wrote:
On Tue, Feb 25, 2025 at 12:39:29AM +0000, Nigel Kukard via Bird-users wrote:
Hi there,
I'm wondering if someone can point out how the best path is being selected below in Bird 3.0.1?
In Bird v2 the route via 100.201.0.2 was selected. With the exact same configuration in Bird v3, the route via 100.201.0.4 is being selected. Hi
I do not think this is really a change. If two routes have the same preference and are originated by the same protocol 'class' (e.g. BGP), they are compared using protocol-specific strategy (e.g. comparing bgp_local_pref, bgp_path length, ... in case of BGP). But in your case these two routes are from different protocols 'classes' (bgp_originate4 -> BGP a static4 -> Static), in that case there is only fixed arbitrary ordering, and that may changed between Bird v2 and v3.
I would suggest that different protocol 'classes' should always use different preference. Hi there Ondrej,
Awesome, that explains it perfectly. Thanks! So just to confirm in this specific case the bgp_local_pref isn't taken into account (ignored) in this specific case, right? -N
In this case R1 is connected to R2. Both with the same ASN. The below table is the table I have facing R2.
In terms of my routing tables... - originate4 =exports to=> bgp4 - static4 =exports to=> master4 - master4 <=exports/imports=> bgp4 - bgp4 <=exports/imports=> t_bgp4_AS65000_r2_peer (below)
1007-Table t_bgp4_AS65000_r2_peer: 0.0.0.0/0 unicast [bgp_originate4 2025-02-24 23:21:13] * (200) via 100.201.0.4 on eth2 1012- preference: 200 source: static bgp_local_pref: 930 bgp_large_community: (65000, 3, 1) 1008- Internal route handling values: 0L 24G 0S id 1 1007- unicast [static4 2025-02-24 23:21:13] (200) via 100.201.0.2 on eth2 1012- preference: 200 source: static bgp_local_pref: 940 bgp_large_community: (65000, 3, 1) (65000, 5000, 1) 1008- Internal route handling values: 0L 22G 0S id 6
Kind Regards Nigel