iBGP over the Internet

iBGP over the Internet

I probably know the answer to this, but is it common to setup iBGP sessions over the Internet? If so, do you establish them over standad GRE tunnels, IPsec tunnels, or just over normal IP? I know BGP doesn't require neighbors to be directly connected, and I figured you cant always connect remote, geographically separated offices...so iBGP over the Internet must be the way to go.

Please see this diagram and the following details for clarification:

• Site A and Site B are separated geographically, but connected to the Internet. They do not have an internal connection (e.g. WAN, dark fiber, etc) connecting them together
• Each site is configured with BGP AS number 200
• Prefix 172.16.0.0/24 is configured at Site A
• Prefix 172.16.1.0/24 is configured at Site B

In this configuration, the two sites cannot talk to each other. The reason being is that Site B will see its AS number in the AS path attribute from Site A updates, and therefore Site B will not accept the update and never learn how to get to Site A, and vice versa.

To fix this I created an iBGP session between Site A and Site B routers.

Thanks