Networking · Routing & Switching
BGP
The path vector protocol that exchanges reachability between autonomous systems and, increasingly, inside data centre fabrics.
AdvancedUpdated 2026-09-01
Overview
Border Gateway Protocol advertises prefixes with attributes, AS path, next hop, local preference, MED and communities, and selects a best path by evaluating those attributes in a defined order. It optimises for policy, not speed.
Enterprises meet BGP at internet edges, in multi homed designs, on SD WAN overlays and in cloud interconnects such as ExpressRoute or Direct Connect. In modern data centres it also runs as the underlay of leaf spine fabrics.
Security considerations
- Filter inbound and outbound prefixes explicitly and use maximum prefix limits.
- Publish and validate RPKI ROAs to reduce hijack and route leak exposure.