Mastering External Routing in Core Engineering Networks

The Internet is a global network of interconnected networks. It is structured hierarchically, with Autonomous Systems (AS) at different levels. An AS is a collection of networks under a single administrative control. Each AS is assigned one or more blocks of IP addresses called prefixes, which they manage.

BGP (Border Gateway Protocol) is an exterior routing protocol used to exchange routing information between different Autonomous Systems (AS) on the Internet. It differs from internal routing protocols (such as OSPF and RIP) as it focuses on routing between AS, while internal routing protocols mainly handle routing within an AS.

BGP uses several attributes to determine the best route for forwarding traffic. The main attributes include the AS Path, Local Preference, Origin, MED (Multi-Exit Discriminator), and Next Hop.

An IXP (Internet Exchange Point) is a physical location where multiple ISPs and networks connect to exchange traffic. It acts as a hub for efficient and cost-effective interconnection between different networks, improving routing efficiency and reducing latency.

Exterior Gateway Routing refers to the process of exchanging routing information between different Autonomous Systems (AS) on the Internet. It is crucial for the Internet's operation as it allows for the global reachability of networks and enables efficient traffic routing across multiple AS.