Zero To BGP Hero

Learn how autonomous systems group routers under a single administrative domain, with numbers assigned by the IANA, including public ranges 1–64,495 and private range 64512–65535.

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.

Explore how a single multi-homed autonomous system uses two ISP connections to boost redundancy, and compare BGP with static routes for reliable path selection.

understand how dual multi-homed autonomous systems use two or more links to multiple service providers, with a full-mesh topology and BGP recommended.

This lecture explains when not to use BGP, highlighting single-homed versus multi-homed setups, bandwidth limits, and the need for skilled resources before enabling BGP.

Use BGP in single or dual multihomed autonomous systems to find the best route to a server and ensure high availability across multiple ISPs and service providers.

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.

Install and use iShare2 in the pnet lab to download and run free images, configure permissions, and test Cisco, Juniper, and other VM images with qemu in a practical lab.

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 BGP attributes influence routing in large networks, covering well-known attributes (mandatory and discretionary) and optional attributes (transitive and non-transitive), including path, next hop, origin, and local preference.

Discover how the Cisco weight attribute, default zero, prioritizes external BGP best paths when increased, using route-maps and access lists, without removing existing 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.

Install Wireshark in the peanut lab, capture an interface, and analyze BGP updates to inspect path attributes, such as aggregator, atomic aggregate, and multi exit discriminator.

Explore the BGP receipt concept, comparing inbound and outbound soft receipts, and learn to use access lists and route maps to control updates without dropping the BGP neighbor.

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.

Learn how BGP maximum path enables multipath routing across multiple links, supporting up to 32 paths for load balancing between two next-hops, with practical router configuration and verification.

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.