The Cisco CCNA exam now requires that you know BGP. This is the exam topic Cisco have listed for the exam: "Configure and verify single-homed branch connectivity using eBGP IPv4 (limited to peering and route advertisement using Network command only)"
In this course you will learn the basics of BGP as well as investigate multiple troubleshooting scenarios to help you prepare for the exam.
Border Gateway Protocol (BGP) is an exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. The protocol is often classified as a path vector protocol but is sometimes also classed as a distance-vector routing protocol. The Border Gateway Protocol makes routing decisions based on paths, network policies, or rule-sets configured by a network administrator and is involved in making core routing decisions.
BGP may be used for routing within an autonomous system. In this application it is referred to as Interior Border Gateway Protocol, Internal BGP, or iBGP. In contrast, the Internet application of the protocol may be referred to as Exterior Border Gateway Protocol, External BGP, or eBGP.
BGP4 is standard for Internet routing, required of most Internet service providers (ISPs) to establish routing between one another. Very large private IP networks use BGP internally. An example is the joining of a number of large Open Shortest Path First (OSPF) networks, when OSPF by itself does not scale to the size required. Another reason to use BGP is multihoming a network for better redundancy, either to multiple access points of a single ISP or to multiple ISPs.