Supermicro MiniSAS HD Connector for PCI-E x16 - 9.84 ft Mini-SAS HD Data Transfer Cable for Add-on Card - First End: Mini-SAS HD

While the number of hosts can vary based on the configuration, in every configuration the cables between the JBOF and the hosts are usually connected from Port A (JBOF) to Port A (Host) and from Port B (JBOF) to Port B (Host). Looking at the L bracket from the outside, there is a clear marking on the end where Cable A should go (and Cable B goes in to the other port).
If two cables are plugged into the AOC, then all x16 lanes will be used. If only Cable A is connected, then it's limited to x8. The table below lists supported cables.