Bgp · Darren Quhttps://darrenqu.net/tags/bgp/Technical writing on network engineering: campus and WAN, hybrid cloud interconnect, automation and observability, and the data center fabrics — InfiniBand, RoCE, Spectrum-X — underneath GPU clusters.Hugoen-USDarren QuDarren Qu2026 Darren QuThu, 10 Sep 2026 00:00:00 +0000BGP Unnumbered and Router Advertisements: Disabling RA Is Not Silence, It Is Withdrawalhttps://darrenqu.net/ai-networking/bgp-unnumbered-router-advertisements/Thu, 10 Sep 2026 00:00:00 +0000https://darrenqu.net/ai-networking/bgp-unnumbered-router-advertisements/AI NetworkingbgpRA drives dynamic peer discovery in BGP unnumbered — and turning it off tears down established sessions instantly, with no flap and no timeout. Why, and what the ND cache does and does not tell you.A BGP Unnumbered Underlay Across Two Vendors: The Route Was There, the Ping Was Nothttps://darrenqu.net/ai-networking/bgp-unnumbered-underlay-across-vendors/Fri, 04 Sep 2026 00:00:00 +0000https://darrenqu.net/ai-networking/bgp-unnumbered-underlay-across-vendors/AI NetworkingbgpArista and Cisco NX-OS, an unnumbered eBGP session, an IPv4 route installed with an IPv6 next hop — and no forwarding. The fix is one interface command, and the reason is RFC 8950.