What is BGP?
BGP is a routing protocol through which autonomous networks advertise paths to IP prefixes.
How it works and where it is used
No single routing table controls the internet. Operators use BGP for policy, connectivity and cost decisions, and announcements can propagate. Incorrect advertisements can reroute traffic or cause outages, whether accidental or malicious.
Limits, safety and selection criteria
Prefix filtering, route validation and RPKI reduce risk but do not instantly secure every network. Troubleshooting needs route history and provider coordination. BGP routes network traffic; DNS maps names to addresses. If an operator mistakenly advertises a more-specific prefix belonging to another network, traffic from parts of the world can take the wrong path. Effects vary because networks apply different policies. RPKI offers a way to validate which network is authorized to originate a prefix, but adoption and filtering matter. Investigating an incident combines route collectors, provider notices and actual application traffic. A valid route announcement is not proof that the destination service itself is healthy.