NextD N2 is capable of supporting Gigabit Ethernet speed. To ensure that you receive the maximum Ethernet speed on NextD, please make sure to use Category 5e or above versions of Ethernet cables between your router and NextD.
For more details on the differences between various category of Ethernet cables, pleas visit this link:
http://ciscorouterswitch.over-blog.com/article-the-different-types-of-ethernet-cables-125299851.html