Transit AS: Carry eBGP across iBGP (next-hop-self)
In this CCNP-level lab (BGP Fundamentals Lab 4/10), you will build a small, realistic transit-AS scenario: an external route learned by R1 via eBGP from AS 65003 must be carried across iBGP to R2 inside AS 65001. You will intentionally encounter the classic iBGP next-hop problem (R2 sees an unreachable next-hop for 172.16.30.0/24) and fix it on R1 with neighbor next-hop-self. iBGP peering runs over Loopback0 addresses with reachability provided by OSPF area 0 between R1 and R2. Two hosts validate end-to-end data-plane reachability and routing control-plane state.
BGP Troubleshooting Capstone: eBGP + iBGP Repair
Advanced CCNP capstone on a compact 3-router, 2-host CML-Free topology. Restore end-to-end reachability to a remote advertised network by diagnosing and correcting two independent BGP issues on the hub router. The design intentionally combines an eBGP edge (R2–R1) with iBGP over loopbacks (R1–R3 with OSPF reachability) so learners validate neighbor formation, next-hop reachability, and route propagation end-to-end.
Lab 3: iBGP over Loopbacks with OSPF Reachability
Build an internal BGP (iBGP) peering between two IOS routers in the same AS over stable Loopback0 addresses, with OSPF providing loopback reachability. Each router originates a /24 from Loopback1 into BGP, and next-hop/peering behavior is validated from end hosts. This lab emphasizes the deterministic neighbor configuration (remote-as, update-source Loopback0, router-id) and exact-match network origination, supported by a minimal, secure OSPF core.
