There is no way to tell. A lot depends on the company that hires you and their pay scale. The same job can have a vast pay range. A lot there can depend on the region of the job as well. Example a network job may make 75k in a small rural town. That same job in a place like New York City may pay upwards of 100K or more. Pick what you are happier with, money is not everything if you hate going to work for the larger paycheck.
While SAP is highly in demand in today’s job market. If you don’t have an interest in networking, you should definitely switch to SAP. Also, from earning and salary point of view, SAP should be ahead than networking.