How long is too long for ethernet?

[smathis11]

I will have a 100ft ethernet cable running from our modem to our router, and then possibly another one running from the router to my xbox 360. Is this too long? Or does the router creating the "break" in between the cables make it not too long?

 

[RealBeast]

No, that length is well within the specifications. You can go 100m between devices with unshielded 24ga wire cable that meets specs and can go farther often with high quality cable. It's best to use CAT5e or CAT6 that will support gigabit.