BIRD Internet Routing Daemon

BIRD (BIRD Internet Routing Daemon) is an open-source routing daemon for UNIX-like systems, developed at the Faculty of Mathematics and Physics of Charles University in Prague, Czech Republic. Originally created by Martin Mares and Ondrej Filip in 1999, BIRD has over 2,000 stars as of 2026 and is widely used by internet service providers, internet exchange points (IXPs), and research networks. BIRD is particularly popular in the ISP and IXP community for its performance, flexibility, and correctness in handling BGP at scale. Key features include: multi-protocol support (BGP, OSPF, RIP, RIPng, Babel, RADV, Pipe, Direct, Static, and Device protocols, with the ability to run multiple protocol instances simultaneously), high-performance BGP (optimized for handling hundreds of thousands of routes and hundreds of BGP sessions, used by major IXPs like DE-CIX, AMS-IX, LINX, and many Tier 1 ISPs), flexible routing policy (a powerful filtering and route map language for controlling route import and export, including AS path filtering, community manipulation, prefix-list matching, and custom route attributes), route redistribution (exchanging routes between different routing protocols with configurable policies), IPv4 and IPv6 dual-stack (full support for both IPv4 and IPv6 routing in a single daemon), multiple routing tables (maintaining multiple independent routing tables for VRF-like functionality and policy-based routing), BGP communities and large communities (manipulating BGP standard communities, extended communities, and large communities for route tagging and policy), multipath and ECMP (equal-cost multi-path routing for load balancing across multiple links), BGP graceful restart (maintaining forwarding state during BGP session restarts for high availability), OSPF area types (supporting normal, stub, and NSSA areas), real-time route monitoring, and MRTcore (Multi-Threaded Routing Toolkit for BGP route logging and analysis).