AS-Path Filtering: Accept Only Neighbor’s Own Routes
Advanced CCNP BGP policy lab focusing on inbound AS-path filtering at the edge. You will build a simple eBGP chain (AS 65003 — AS 65002 — AS 65001), originate prefixes from the two upstream routers, confirm that the edge learns multiple routes, then enforce a policy on the edge (R1) to accept only routes originated by its directly connected eBGP neighbor (AS 65002) while rejecting routes that transited AS 65003. Verification relies entirely on R1’s BGP table and AS-path regular-expression queries.
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 Lab 5: Local Preference - Preferred Exit
Configure and validate BGP local-preference to prefer one provider when the same destination prefix is learned from two eBGP neighbors. You will see two equal AS-PATH routes to 172.16.100.0/24 on the edge router and then apply an inbound route-map on the R2 session to set local-preference 200 so the edge prefers exiting via R2. Verification includes host pings/traceroute and router BGP best-path checks.
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.
BGP Lab 7: Filtering Advertised Prefixes (Prefix-List)
Deploy eBGP between two routers and precisely control which locally-originated networks are advertised to a neighbor using an outbound prefix-list. R1 originates four /24 loopback routes but advertises only two to R2. Verify using IOS show commands and basic host reachability checks.
BGP Lab 2: Exact-Match Prefix Origination
Configure eBGP between two routers and originate select connected /24s using the exact-match 'network ... mask' command. Verify that only the intended prefixes are advertised and learned by the neighbor, and use host-based tests to confirm reachability to the advertised networks. This beginner CCNP lab reinforces that the BGP network statement only advertises a route if an exact match exists in the RIB, and that the 'mask' keyword is mandatory for non-classful advertisements.
Inbound Steering: AS-Path Prepending (Primary/Backup eBGP)
Advanced CCNP BGP lab: Build parallel eBGP sessions between two ASes over primary and backup /30 links. Originate a service prefix from AS 65001 and influence AS 65002's inbound path by applying outbound AS-path prepending on the backup session only. Validate best-path selection and next-hop on the neighbor, and confirm reachability from hosts.
eBGP Fundamentals: The First Peering
Build your first external BGP (eBGP) peering between two routers in different autonomous systems over a /30 point-to-point link and exchange one /24 prefix from each side using Loopback0. The topology is intentionally small yet realistic, with two edge routers (AS 65001 and AS 65002) and three Alpine hosts for basic reachability checks and operator context. You will configure deterministic BGP neighbors, originate prefixes with exact-match network statements, and validate reachability and route installation using standard IOS and Linux tools. This is Lab 1 of 10 in the CCNP-aligned BGP Fundamentals series and sets the foundation for later labs on iBGP, route filtering, and path selection.
