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 Path Attributes Explained: Well-Known vs Optional

BGP path attributes are the foundation of every traffic engineering technique: local preference, MED, AS-path prepending, communities. Understand the well-known vs optional attribute matrix before touching policy.

Mar 28, 2026 4 min read

BGP

BGP Message Types: OPEN, UPDATE, KEEPALIVE, and NOTIFICATION

BGP uses just four message types: OPEN, UPDATE, KEEPALIVE, and NOTIFICATION. Understanding the field-level format of each makes debug output and packet captures far more readable for anyone troubleshooting BGP.

Mar 28, 2026 4 min read

BGP

eBGP vs iBGP: What's the Difference and When to Use Each

eBGP and iBGP look similar at a glance but behave very differently around TTL, next-hop, AS-path, and route advertisement. Treating them as the same protocol gets you in trouble fast; here are the rules.

Mar 28, 2026 4 min read

BGP

How BGP Works: Peers, Updates, and the Finite State Machine

BGP peering does not auto-discover. Every session is deliberately configured, runs over TCP port 179, and walks a strict finite state machine before a single route flows. The foundation you need before touching BGP config.

Mar 28, 2026 4 min read

BGP

What Is BGP? The Protocol That Runs the Internet

Every time you load a webpage, your traffic crosses networks owned by different organizations. BGP, the Border Gateway Protocol, is what stitches 75,000+ autonomous systems into a single working internet. Here is how, and why.

Mar 28, 2026 4 min read

BGP

BGP Route Filtering with Prefix Lists

Prefix lists are the preferred BGP filtering tool: faster than ACLs, easier to read, and built for matching networks with specific prefix lengths. Every production BGP deployment needs them on inbound and outbound.

Mar 28, 2026 5 min read