The general steps for implementing BPG multihoming are:
- Obtain your ASN from ARIN.
- Identify your network block of IP addresses. If you own these, then you have the right to advertise them on the Internet through BGP. If you are borrowing these from your provider, then you must ask your provider for permission before advertising them through another provider.
- If you have a single provider, you are typically using a static route to connect to that provider. That provider is not sending you any BGP routes. Assuming that is true, you will have to request that your provider send you BGP routes. (Your provider will need to know your ASN and your remote router’s neighbor address. The neighbor is the IP address that your BGP process uses to communicate with.) Once you have the provider's BGP routes in your routing table and you are advertising your network to your provider through BGP, you can remove your static route and have your provider remove their static route.
- Next, assuming that you are multihoming on a single router, bring up your secondary provider. They can set it up so that they send you BGP routes. Again, they will need to know your ASN and your neighbor address.
- Within the BGP table (database) on your router, you will see the routes from each of your providers. The best route in BGP is the route with the shortest AS path. (If the AS paths are identical, there is a tiebreaking procedure, but this is normally not the case.) The route that has the shortest AS path will be placed in your router’s routing table.