Border Gateway Protocol (BGP) is one of the key protocols to use to achieve Internet connection redundancy. When you connect your network to two different Internet service providers (ISPs), it is called multihoming. Multihoming provides redundancy and network optimization. It selects the ISP which offers the best path to a resource. When you are running BGP with more than one service provider, you run the risk that your autonomous system (AS) will become a transit AS. This causes Internet traffic to pass through your AS and potentially consume all of the bandwidth and resources on the CPU of your router. This document addresses this issue, with appropriate configuration examples.
BGP Detailed Information
This module presents the basic concepts and terminology of BGP. You learn the basic Cisco IOS Software BGP commands and configure basic BGP settings on a Cisco simulated router network, creating BGP loop-free interdomain routing between autonomous systems (ASs) in our Configuration Labs.