Question about REFCLK_GXB_CHB and REFCLK_GXB_CHT in Tranceivers of Arria10 SX

Hi, what's the difference between REFCLK_GXB_CHB and REFCLK_GXB_CHT in Tranceivers of Arria10 SX？

Does the "CHB" refer to Bottom and "CHT" refer to Top?

I plan to design a SRIO 4x in a tranceiver bank，should I connect both CHB and CHT to a clock source individually，or just connect one of them to a clock source while connect the other one to GND？

Thanks.