Equivalent product for CSS 11501

And is there any license required?

Best I can tell, the Cisco CSS products are rated by aggregate throughput (6 Gpbs for the 11501) . If that's the only comparative factor, then the F5 6900 supports 6 Gbps. The new 2000 series supports 5 Gbps, and the new 4000 series supports 10 Gbps.

 

F5 Hardware datasheet

 

As for licensing, please refer to the following site for information on what you can do with the platform.

 

http://www.f5.com/products/big-ip/