Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

bgpd: remove dmed check not required in bestpath selection (backport #18210) #18227

Open
wants to merge 1 commit into
base: dev/10.3
Choose a base branch
from

Conversation

mergify[bot]
Copy link

@mergify mergify bot commented Feb 21, 2025

As part of the upstream master commit (f3575f6 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
```<hr>This is an automatic backport of pull request #18210 done by [Mergify](https://mergify.com).

As part of the upstream master commit (f3575f6 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 83ad946)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
Development

Successfully merging this pull request may close these issues.

1 participant