Networking & Internet
BGP
Definition
The Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. It is the protocol that makes the internet work.
Why It Matters
BGP is the routing protocol of the internet's backbone. It allows the large networks (like ISPs and major content providers) that make up the internet to tell each other which IP addresses they are responsible for, creating a global map of the internet.
Contextual Example
When an ISP gets a new block of IP addresses, it uses BGP to "announce" to its neighboring networks that it is now the correct path to reach those addresses. This information then propagates across the entire internet.
Common Misunderstandings
- BGP is an "exterior" gateway protocol, used between different large networks. "Interior" gateway protocols (like OSPF) are used within a single network.
- BGP misconfigurations can have catastrophic consequences, potentially taking large parts of the internet offline.