CCIE-level material for engineers past the CCNP line. Articles tagged CCIE cover expert-track routing, overlays, security and automation, with full configs and real device output from CML.
6PE carries IPv6 prefixes across an untouched IPv4 MPLS core using MP-BGP and labels. This post builds a working deployment on Cisco IOS XE and shows the labels, the IPv4-mapped next hops, and an end-to-end IPv6 traceroute.
BGP multipath is one config line, but the rules for when a second path is accepted are not. Cover eBGP, iBGP, and eiBGP multipath on Cisco IOS XE with lab output, including the next-hop rewrite that can hide a real misconfiguration.
A well-designed BGP community scheme turns per-neighbor route-maps into a scalable signaling system. This guide builds one end to end on IOS XE, proves it with lab output, and includes a working RTBH trigger.
Dampening penalises a prefix for flapping and refuses to use it even after it recovers. Captured live on CML with IOS XE 17.18.2: penalty 2818 from three flaps, the prefix held at *d while an identical prefix from the same neighbor stays best, plus the advertisement-interval gotcha that makes...
ORF pushes your inbound prefix filter to your BGP neighbor so unwanted routes never leave their router. Shown working on Cisco IOS XE with real CML output, including the commands the receiving router uses to see the filter you sent it.
BGP conditional advertisement withholds a prefix until a condition you define is no longer true. Walk through advertise-map, exist-map, and non-exist-map on Cisco IOS XE to keep a backup path truly idle.