BGP

Border Gateway Protocol, the path-vector protocol that holds the internet together and increasingly runs inside enterprise data centers. Articles tagged BGP cover fundamentals, neighbor states, path attributes, best-path selection, traffic engineering, and Cisco IOS XE configuration.

36 posts

BGP Field Reference (9-Page Printable Cheat-Sheet)

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BGP

BGP Field Reference (9-Page Printable Cheat-Sheet)

BGP has a lot of moving parts. The state machine. The 13-step path-selection algorithm. The dozen knobs that influence which

May 8, 2026 3 min read

GRE

Routing Protocols Over GRE: OSPF, EIGRP, BGP

Run OSPF, EIGRP, and BGP across GRE tunnels on Cisco IOS XE. Recursive routing fix, OSPF network types, EIGRP metric tuning, and BGP update-source.

May 1, 2026 8 min read

MPLS

MPLS L3VPN with MP-BGP and VPNv4

MPLS L3VPN architecture: VRFs, Route Distinguishers, Route Targets, MP-BGP for VPNv4, the two-label stack, PE-CE routing, and the Cisco IOS XE configuration.

Apr 26, 2026 7 min read

BGP

MP-BGP: Multiprotocol BGP Address Families Explained

MP-BGP (RFC 4760) is what lets a single BGP session carry IPv6, VPNv4, EVPN, and more. The AFI/SAFI model, route distinguishers, and how modern data center fabrics use MP-BGP for everything.

Apr 25, 2026 6 min read

BGP

BGP Neighbor States: The 6-State FSM and How to Diagnose It

BGP's finite state machine has six states: Idle, Connect, Active, OpenSent, OpenConfirm, Established. What each means, why Active is a problem state, and the diagnostic that maps each stuck state to a real cause.

Apr 25, 2026 7 min read

BGP

BGP vs OSPF: When to Use Each Routing Protocol

BGP and OSPF solve different problems and almost always run together in production. The technical differences, when each is the right answer, and the architecture pattern most enterprises end up with.

Apr 25, 2026 7 min read