By default, BGP balances traffic across one path. You can use the multipath feature to enable load-balancing across different BGP4 paths.
When BGP4 multipath load sharing is enabled, iBGP and eBGP paths are eligible for load sharing. Paths from different neighboring autonomous systems are not eligible. You can change load sharing to apply only to iBGP or eBGP paths, or to support load sharing among paths from different neighboring autonomous systems.