1. Opening Confederations are another way to scale BGP inside a large administrative domain. They divide the domain into member autonomous systems while presenting a single confederation identifier to external peers. They are powerful, but their operational model is more complex than simply 'using private ASNs inside.' The engineering goal is not to memorize another BGP command. It is to understand what information each speaker is allowed to propagate, what path information can be hidden, and what failure domain is created by the chosen control-plane architecture . 2. Concept and standards behavior RFC 5065 defines AS_CONFED_SEQUENCE and AS_CONFED_SET and how member-AS relationships are represented. Confederation external sessions have eBGP-like properties inside the confederation, while the confederation is presented externally as one AS. Modern guidance must also account for the fact that RFC 9774 prohibits new origination of AS_SET/AS_CONFED_SET in ordinary aggregation c...