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

BGP Convergence: Timers, BFD, and Reducing Failover Time

Default BGP convergence can take 3 minutes to notice a dead peer. That is fine on the public internet and unacceptable in enterprise or data center BGP. Every knob for reducing BGP failover time on Cisco IOS XE, including BFD.

Mar 28, 2026 4 min read

BGP

Why Is BGP Choosing the Wrong Path? Troubleshooting Best Path

You set local-pref, route maps, and communities, and traffic still goes the wrong way. BGP is deterministic; a surprise path means either policy is not applied where you think, or a higher priority step decided first.

Mar 28, 2026 4 min read

BGP

Troubleshooting BGP Route Advertisement Problems

The BGP session is Established but routes are missing. A missing prefix can be stopped at any of several pipeline stages, from injection to best path to output filtering. A methodical troubleshooting guide to BGP route advertisement.

Mar 28, 2026 4 min read

BGP

Troubleshooting BGP Neighbor Adjacency Issues

A BGP session that will not reach Established is the most common BGP issue. The FSM state tells you exactly where the problem is; the root cause inside each state can be one of many things. A systematic IOS XE methodology.

Mar 28, 2026 4 min read

BGP

BGP Design for Service Providers: Full Tables, Peering, and Transit

Service provider BGP operates at a scale that dwarfs enterprise: full tables, hundreds of peers, thousands of routers. An SP BGP design guide covering peering relationships, policy, iBGP scaling, and transit economics.

Mar 28, 2026 5 min read

BGP

BGP Design for Enterprise Networks: Dual-Homed and Multi-Homed

Enterprise BGP design comes down to how many ISPs, how many borders, full table or defaults, and active-active or active-standby. From single-homed to multi-homed with traffic engineering, and when you do not need BGP at all.

Mar 28, 2026 4 min read