Zero To BGP Hero

Explore single home autonomous systems by linking a company to an ISP through one connection, creating an isolated network with a default route or private autonomous system. BGP is optional.

Discover the dual homed autonomous system type with two backup links to the same or separate edge routers and an ISP, and learn when static or default routes trump BGP.

Explain the difference between external BGP and iBGP: external BGP spans different autonomous systems, while iBGP stays inside one autonomous system, with transit routing scenarios.

Learn the BGP routing algorithm, including tcp-based neighbor handshake on port 179, the absence of multicast, and path vector decision with internal versus external administrative distance.

Manually configure bgp neighborship on both routers, ensure reachability over tcp port 179, and advertise networks after establishing the session, since multiple sessions to the same neighbor are not permitted.

Learn to set up internal routing with OSPF and configure BGP across two ISPs, advertise networks, verify adjacency and routing updates, and explore redistribution and default routes.

Explore how the local preference attribute in iBGP biases route selection, default 100, higher values preferred, and how to set it to 110 with a route map.

explains the BGP MED attribute and how it drives path selection between multiple exits from an autonomous system, with a lab demonstrating metric adjustments via route maps.

Learn how autonomic aggregate and the aggregator in BGP summarize multiple routes into a single prefix, and verify using show ip bgp.

Explore how BGP dampening mitigates route flapping by applying penalties and suppression, using parameters like initial penalty, reuse value, suppressed limit value, half time, and maximum duration to control advertisement.

This lab demonstrates configuring BGP dampening on select routes with access lists and route maps, applying dampening parameters, and testing by flapping a loopback to observe dampening and route suppression.

Explore how BGP ORF enables outbound route filtering by sending an ORF message with an IP prefix list to neighbors, allowing rejection or acceptance of prefixes to prevent link congestion.

explains how a bgp route reflector reduces ibgp mesh by designating routers as route reflectors and reflecting routes to rr clients, with lab demonstrations of reflector rules.