Question : FVS318G gigabit WAN but 25megabit throughput on broadband?

FVS318G Why does it have a gigabit WAN but I read it has 25megabit throughput on broadband?

"Providing IPsec VPN for secure remote connections and firewall functions to protect small business networks from hackers, the FVS318G offers peace of mind and security while also enabling fast networking by offering eight gigabit ports, one gigabit WAN port, and up to 25 megabit per second broadband throughput. Unique for its price point, the FVS318G also features a software-configurable hardware DMZ port to provide for server and other externally facing connections."

http://redhat.sys-con.com/node/1073415

Answer : FVS318G gigabit WAN but 25megabit throughput on broadband?

     
Performance Specifications:
Throughput:
Up to 11.5 Mbps for WAN-to-LAN and up to 2.1 Mbps for 3DES