BGP Fundamentals

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.

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.

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.

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.

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.

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.

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.

In this advanced CCNP BGP lab, you will steer a single router's outbound path choice using Cisco's Weight attribute, the very first BGP best-path tiebreaker. R1 (AS 65001) peers eBGP with two ISPs (R2 in AS 65002 and R3 in AS 65003). Both ISPs advertise the same prefix 172.16.50.0/24. Your job is to make R1 prefer the R3 path using the neighbor weight command and verify the outcome using IOS and Linux tools.

Advanced BGP capstone, run as a fault hunt. The hub lost its upstream service route overnight and the branch cannot see hub prefixes either. Sessions are not all down, which is what makes it interesting: one peering never establishes, one establishes and carries nothing, and one prefix is never originated at all. You get symptoms and the required end state — no fault list. Faults span all three routers, and one of them is not in BGP at all.