I wnant more information a about type of networking such as t1 , t2 , t3 what is it? And what the requirements do?

T1 and T3 aren't types of networking, really. They're types of connections BETWEEN networks... usually they're internet connections. A T1 is a basically a set of data channels you get from the phone company (You can get them other places... but mainly people get them from the phone company). That T1 is split into, depending on what country you're in, usually 24 different channels. Of these 24 channels, some can be used as phone lines, and the rest are used for data transfer (basically, your internet connection). You need special equipment connected to the T1 line to be able to use it correctly.

A T3 is a bit different. It comes in over a different type of cable, and provides several T1s, all within the same line. Whereas a T1 can support 1.544megaBits of bandwidth, a T3 can support about 45megaBits.

t1, 2, and 3 are connection speeds!