The complete Border Gateway Protocol series — from foundational concepts to service provider design. 30 articles covering eBGP, iBGP, path selection, route filtering, traffic engineering, troubleshooting, and BGP security. Built on Cisco IOS XE 17.x with a consistent lab topology throughout.
Fundamentals
1. What Is BGP? The Protocol That Runs the Internet
2. How BGP Works: Peers, Updates, and the Finite State Machine
3. eBGP vs iBGP: What's the Difference and When to Use Each
4. BGP Message Types: OPEN, UPDATE, KEEPALIVE, and NOTIFICATION
5. BGP Path Attributes Explained: Well-Known vs Optional
6. BGP Best Path Selection Algorithm — All 13 Steps
7. How BGP Advertises Routes: NLRI, Withdrawn Routes, and the Adj-RIB
Configuration
8. How to Configure eBGP Neighbors on Cisco IOS XE
9. How to Configure iBGP Neighbors and Full Mesh
10. BGP Next-Hop-Self: When and Why You Need It
11. BGP Route Reflectors: Eliminating the Full Mesh
12. BGP Confederations: An Alternative to Route Reflectors
13. BGP Route Filtering with Prefix Lists
14. BGP Route Maps: Matching, Setting, and Manipulating Paths
15. BGP Communities: Standard, Extended, and Large
Traffic Engineering
16. Manipulating BGP Local Preference for Inbound Path Selection
17. BGP MED (Multi-Exit Discriminator): Influencing Inbound Traffic
18. BGP AS-Path Prepending: When It Works and When It Doesn't
19. Cisco BGP Weight Attribute: Local Path Preference
20. BGP Route Aggregation and Summarization
21. Originating a Default Route in BGP
22. BGP Session Authentication: MD5 and TCP-AO
Troubleshooting
23. Troubleshooting BGP Neighbor Adjacency Issues
24. Troubleshooting BGP Route Advertisement Problems
25. Why Is BGP Choosing the Wrong Path? Troubleshooting Best Path
26. BGP Convergence: Timers, BFD, and Reducing Failover Time
Security
27. BGP Route Leaks and Hijacks: Detection and Prevention
28. BGP RPKI and Route Origin Validation on IOS XE
Design & Architecture
29. BGP Design for Enterprise Networks: Dual-Homed and Multi-Homed
30. BGP Design for Service Providers: Full Tables, Peering, and Transit
