Networking Glossary

Announcing the same prefix from multiple locations so each user reaches the nearest instance - used by DNS resolvers and CDNs.

The ordered list of ASNs a BGP route has traversed, used for loop prevention and path selection.

A signed RPKI object listing an ASN's authorized upstream providers, enabling validation of the AS-path - not just the origin.

A globally unique number identifying a network (autonomous system) that runs its own routing policy on the internet.

When a network announces IP prefixes it is not authorized to originate, redirecting or intercepting traffic - accidentally or maliciously.

An IP address or prefix that should never appear in the public routing table - private, reserved, or unallocated space.

The routing protocol that exchanges reachability information between autonomous systems and steers traffic across the internet.

The notation and allocation scheme that writes IP ranges as address/mask (e.g. 10.0.0.0/8), replacing the old class A/B/C system.

A CSV file, published by the address holder per RFC 8805, mapping their prefixes to geographic locations for accurate geolocation.

A block of contiguous IP addresses written in CIDR notation, such as 192.0.2.0/24 - the unit of routing in BGP.

A distributed database of route objects declaring which ASN intends to originate which prefix, used to build routing filters.

Physical infrastructure where many networks interconnect to exchange traffic directly, reducing cost and latency versus paid transit.

A prefix that appears in BGP with more than one origin ASN - sometimes legitimate (anycast, multihoming) and sometimes a sign of hijacking.

A prefix with a longer mask that covers part of a larger block; it always wins in routing over the less-specific covering route.

A voluntary interconnection where two networks exchange traffic between their own customers directly, usually without payment.

One of five regional bodies (RIPE NCC, ARIN, APNIC, LACNIC, AFRINIC) that allocate IP address space and ASNs.

A signed RPKI object in which a prefix holder declares which ASN may originate the prefix, and the maximum prefix length allowed.

A ROA is the signed authorization published by the address holder; ROV is the act of validating routes against ROAs. One is data, the other is the check.

The process of checking a BGP route's origin ASN and prefix length against published ROAs, yielding valid, invalid, or not-found.

A cryptographic system that lets address holders authorize which ASN may originate their prefixes, so routers can reject invalid announcements.

A paid service where a provider carries a customer network's traffic to and from the entire internet.