Well that is still pretty vague, but, when you say connection speed I am assumming you mean bandwidth. Generally, that is the consideration, how much bandwidth the circuit has. The range is dependant on antenna gain and frequency of the microwave. As for line of sight, absolutely necessary.
Here are some general parameters. Systems in the 2,4,6 Ghz range can make make hops up to about 45 miles. When you get into the higher bands such as 18, 23, and 45 Ghz the range tends to be much shorter such as 1 to 5 miles.
Bandwidth is pretty variable, depending on the system and operating frequency, but can offer in excess of 30 MHz.
Line of sight is essential, in fact more than essential. Not only do both antennas have to be able to see each other, there are fresnel zones along that path that also must be relatively free from obstruction. Amount of precipitation in the area, fog, soil conductivity, standing water, etc can cause problems in the path as well.
Source - Telecommunications Essentials by Lillian Goleniewski
Hope that helps It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com