Difference between BUFGDS and IBUFDS on clocks

Dear all, I'm a little bit confused about the usage of IBUFGDS and
IBUFDS. In my design (on a XC2V8000 fpga) I have to acquire LVDS input
data using a LVDS clock which comes from an external board. It is not
really clear to me which is the best between these 2 options

1) use IBUFGDS on clock and then drive a BUFGMUX

2) use IBUFDS on clock and then drive a BUFGMUX

Data input goes to IBUFDS. In both cases the output of BUFGMUX is a
global line, so I don't understand which is the best option and the
differences between IBUFGDS and IBUFDS.

Any advice about that ?


Thanks in advance.