BGP, short for Border Gateway Protocol, is an internet protocol that allows to exchange routing information between and within networks.
With BGP you can announce your own IP prefixes to an upstream (provider) or peer using your own ASN.
To make a BGP announcement you need to install a BGP Daemon on your Server or Router. This software will then talk to your upstream/peer.
We recommend using Bird for BGP. Bird is a powerful yet easy-to-use software to make your BGP announcements with your own ASN.
You can find a guide on how to install bird here: bgp.training/bgp/first-bgp-session
Bird uses config files, if you like the cisco cli style more, have a look at FRR.