BGP Troubleshooting

BGP Address Families: One Protocol, Many Tables, Infinite Confusion

| | Leave a Comment | BGP, BGP Configuration, BGP Fundamentals, BGP Troubleshooting, Networking, Routing Protocols

Here’s something that surprises people who are new to BGP. The same protocol that’s been routing IPv4 across the internet since 1994 also handles IPv6, MPLS VPNs, EVPN, multicast routing information, and several other things you might not expect. Not through separate protocols. Through address families. Once you understand address families, BGP stops being “that

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BGP Confederations Explained: The Dark Art of Splitting Your AS

| | Leave a Comment | BGP, BGP Configuration, BGP Fundamentals, BGP Scaling, BGP Troubleshooting, Networking, Routing Protocols

If you mention BGP confederations in a group of network engineers, you’ll get a split reaction. Some people will immediately recognize what they are and nod knowingly. Others will tilt their head slightly like a dog that heard a strange sound. Both reactions are completely reasonable. Confederations solve the same problem as route reflectors, which

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What Is Next-Hop Self and Why Is It the First Thing You Break?

| | Leave a Comment | BGP, BGP Configuration, BGP Fundamentals, BGP Scaling, BGP Troubleshooting, Networking, Routing Protocols

Here’s the scenario. You configure iBGP between your edge routers and your internal routers. Sessions come up. You see routes in the BGP table. Everything looks right. And then you ping a destination that should be reachable and it fails. show bgp ipv4 unicast x.x.x.x/y shows the route. show ip route x.x.x.x shows the route in the routing

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