Multipath
When a pair of links, over which two eBGP sessions are configured and built, connects two autonomous systems, only one of the two paths will be used to forward traffic between the two autonomous systems. The BGP route selection algorithm will always select one path or the other as the best path, even if the paths are equal up to the point of the router ID of the advertising router. Thus, one link is the primary, and all traffic is carried on this link, and the other link is redundant, with little or no traffic carried along it.
Generally, the only way to use this second link is to direct traffic outbound towards the Internet through it in some way, which normally involves some method of splitting the outbound traffic using manual configurations ...
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