Clock Source Internal

[pbarman]

Suppose I have two T1 controllers on a routerA, 1/0 and 2/0. T1 1/0 is taking the clock from the line, using command clock source line. On the T1 2/0 controller I configuired clock source internal. So, what clock will the T1 2/0 provide to the line, will it be the clock it is receiving from the T1 1/0? I have connected another routerB to T1 2/0 of routerA, and configured that router's interface for clock source line. So, with this configuration is the routerB receiving the clock that routerA's T1 1/0 is getting from its line?

[jsalminen]

When you specify clock source internal, you are telling the router to generate the clock signal on that one particular line. All other lines will (by default) receive the clock signal from the line. When you generate the clock on your router you are making the router the DCE, whereas the router is setup by default as the DTE. Each separate T1 line you have connected to the router must either be listening or generating the clock signal.