As part of the upstream master commit (f3575f61c7 bgpd: Sort the
bgp_path_inf) the snippet of the code for dmed check condition
left out, which leads to an issue of selecting incorrect bestpath.
As an example:
During the bestpath selection local route looses to another path due
to dmed condition being hit.
The snippet of the logs:
2025/02/20 03:06:20.131441 BGP: [JW7VP-K1YVV]
[2]:[0]:[48]:[00:92:00:00:00:10](VRF default): Comparing path
27.0.0.7 flags Valid with path Static announcement flags Selected Valid Attr Changed Unsorted
2025/02/20 03:06:20.131445 BGP: [SYTDR-QV6X9] [2]:[0]:[48]:[00:92:00:00:00:10]: path 27.0.0.7 loses to path Static announcement as ES 03:44:38:39:ff:ff:02:00:00:01 is same and local
2025/02/20 03:06:20.131452 BGP: [JW7VP-K1YVV] [2]:[0]:[48]:[00:92:00:00:00:10](VRF default): Comparing path 27.0.0.8 flags Valid with path Static announcement flags Selected Valid Attr Changed Unsorted
2025/02/20 03:06:20.131456 BGP: [SYTDR-QV6X9] [2]:[0]:[48]:[00:92:00:00:00:10]: path 27.0.0.8 loses to path Static announcement as ES 03:44:38:39:ff:ff:02:00:00:01 is same and local
2025/02/20 03:06:20.131458 BGP: [WEWEC-8SE72] [2]:[0]:[48]:[00:92:00:00:00:10](VRF default): path Static announcement is the bestpath from AS 0 <<<< static is best
2025/02/20 03:06:20.131463 BGP: [Z3A78-GM3G5] bgp_best_selection: [2]:[0]:[48]:[00:92:00:00:00:10](VRF default) pi 27.0.0.7 dmed
2025/02/20 03:06:20.131467 BGP: [Z3A78-GM3G5] bgp_best_selection: [2]:[0]:[48]:[00:92:00:00:00:10](VRF default) pi 27.0.0.8 dmed
2025/02/20 03:06:20.131471 BGP: [N6CTF-2RSKS] [2]:[0]:[48]:[00:92:00:00:00:10](VRF default): After path selection, newbest is path 27.0.0.7 oldbest was Static announce
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 83ad94694b)
FRR is free software that implements and manages various IPv4 and IPv6 routing
protocols. It runs on nearly all distributions of Linux and BSD and
supports all modern CPU architectures.
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Participate section of our website.
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We welcome and appreciate all contributions, no matter how small!
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