Quagga is available in the default package managers of most distros so its a good place to start.
And they have their own apt repo at deb.frrouting.org for other Debians.
Microsoft runs FRR on SONiC.
Vyos runs FRR.
6wind runs FRR.
Cumulus Networks runs FRR.
Juniper runs FRR in certain products.
VMware runs FRR.
Broadcom is integrating it.
I don't think you are very familiar with the scope of changes that have gone in since Quagga. Not to detract from BIRD - which is a great, solid BGP implementation - but it is disingenuous to say FRR isn't used in production.
Would you trust two compared TCP implementations using those stats as well?
For something simple like this post, using quagga is completely fine and probably much better that using the latest Swiss Army knife.
The Quagga source repo[1]'s certificate expired over 6 months ago. Looking at the Bugzilla[2] report (also with an expired certificate) there are 14 blockers, 49 critical and 69 issues that have not been resolved.
So no, I'd agree with the parent comment that using a project as seemingly dead as Quagga for something as critical as BGP routing is putting yourself on shaky ground at the very least.
1. https://gogs.quagga.net/Quagga
2. https://bugzilla.quagga.net/report.cgi?x_axis_field=bug_seve...
It’s like someone doing a demo on some text processing where they use grep and the top comment is some jerk saying that map-reduce would be better because some new large systems use it and it’s being actively developed.