BGP Explorer
The internet is 80,000+ networks. BGP is how they decide where to send your traffic. Pick a source, pick a destination. Watch the path form.
AS topology
What just happened
Topology overview
BGP RIB: all candidate routes
Equivalent of show ip bgp {destination} on the source router. Best path marked with >.
| AS_PATH | Next Hop | LP | MED | Origin | Hops |
|---|
Find a path first to populate the route table.
AS detail
Nerd tip
The full BGP table has over 1 million IPv4 prefixes. Your home router never sees them. Your ISP's edge router does. It runs BGP with hundreds of peers, each advertising thousands of routes. The decision process you see here runs for every single prefix, every time an UPDATE arrives.
Nerd tip
RPKI/ROA validation is the internet's attempt to prevent hijacks like the one you can simulate above. Route Origin Authorizations let prefix owners cryptographically sign which AS is allowed to originate their routes. As of 2025, roughly 50% of routes are covered. The other half is still vulnerable.
Nerd tip
Best-path selection is a tiebreaker tree, not shortest path. The order is, roughly: highest WEIGHT (Cisco-local), then highest LOCAL_PREF, then locally-originated, then shortest AS_PATH, then lowest ORIGIN (IGP beats EGP beats incomplete), then lowest MED (only if same neighbor AS), then eBGP over iBGP, then lowest IGP metric to the next hop, then oldest route, and finally lowest router-ID. AS_PATH length is step four, not step one. An operator who wants traffic to take a specific path does not shorten the path, they raise LOCAL_PREF. That is why BGP engineering feels like policy, not routing.
Nerd tip
MRAI, route dampening, and the thundering hand of convergence. A single link flap can send an UPDATE through thousands of ASes. The Minimum Route Advertisement Interval (30 seconds, default) smooths this by rate-limiting announcements to each peer. Route flap dampening goes further, suppressing a prefix that has flapped too often in a short window. Both are the reason BGP's loose-consistency convergence stays tolerable on a million-prefix table. The 1997 AS 7007 incident, a misconfiguration that leaked the global table to the internet through a small ISP, is the textbook reason these defaults exist.