I would like to experiment with different serial links. I would like to practice with frame-relay. I would like to try configuring point-to-multipoint and point-to-point. So I want to have subinterfaces like S0.1 S0.2 and so on.
So I guess my question is, how in the world do you get more than one line into a single serial port!? And then after that what in the world does the serial port connect to, in order to get to the outside net? Don't nearly all businesses today use DSL or cable? Both of these require a Fast Ethernet cable, not a serial cable. So ugg, i'm so confused about WANS now.
My equipment to work with is 4x2501 routers and a 2924 switch.
I am going to suggest that you pick up a 2520/2522 router which have 4 or 8 serial ports, to be used as a Frame Switch.
Have a look here for how to configure your Frame Switch http://www.thebryantadvantage.com/Frame%20Relay%20Switch.htm along with an explanation.
Then have a look at this link for point to multipoint configuration http://dynagen.cn/?p=28
And this link for point to point http://7200emu.hacki.at/viewtopic.php?t=3187
Both of these links are geared towards using Dynamips, however as Dynamips uses real IOS software, this is relevant on real hardware also. Also both cover the configuration of the Frame Switch to work with the configuration shown
Whatever study material you are using should also cover Frame Relay so you shoud be able to configure Frame Relay from that.