The text discusses the Border Gateway Protocol (BGP), a signaling protocol used by autonomous systems on the internet to exchange information about IP prefixes and routing decisions. It explains how traffic engineering is done using prepending, which artificially increases the AS-path length to influence other networks' choices. The text also highlights that BGP is colloquially referred to as a Business Policy Engine because it selects the best path from a business point of view rather than performance. Furthermore, it discusses how community-based local preference can be used for ingress traffic engineering when prepending isn't effective or available.