What Is the Meaning of PCIE Uplink about Intel® Chipset C622?

Intel® Compute Module HNS2600BPQ Intel® Compute Module HNS2600BPS Intel® Compute Module HNS2600BPQ24R Intel® Compute Module HNS2600BPBLC24 Intel® Compute Module HNS2600BPSR Intel® Compute Module HNS2600BPS24 Intel® Compute Module HNS2600BPS24R Intel® Compute Module HNS2600BPB24 Intel® Compute Module HNS2600BPQ24 Intel® Compute Module HNS2600BPBLC Intel® Compute Module HNS2600BPB24R Intel® Compute Module HNS2600BPB Intel® Compute Module HNS2600BPBLC24R Intel® Compute Module HNS2600BPBLCR Intel® Compute Module HNS2600BPQR