Default route or full routing table?

When a company/enterprise is signing up with an ISP for internet access, they are able to connect in many different ways, but we are going to go over a couple of the popular methods.

NOTE: This is a brief overview to answer this one question, BGP is very powerful and programmable, so we won’t touch on most of its features.

If the company has its own ASN (Autonomous System Number) they can connect to an ISP and advertise out this number through BGP with the IP space (prefixes) they own. That way other participants in BGP can find the best path to get to that company/ASN and the IP space. Companies will typically get an ASN if they are an ISP or if they are hosting some sort of content that others need to access. You can think of content as a website, portal, video, audio, VPN, or anything else that someone else needs to connect to from somewhere else. A large majority of the time this content is “in the cloud” instead of on-premise, but many larger organizations have their own equipment and data centers to handle accessing this content.