The 6th gen is the 128-bit era, this is the time of the ps2, xbox, game cube and sega dreamcast, there was apperintly another console called the XaviXPort but i never heard of it. This era ended arounf 2005 when the xbox 360 came out.
Front Mission Online, this is the only one title from the series in PS2 platform which player can combat online. Choose your side, OCU or USN. The player will play using mech called wanderpanzer (wanzer) ... well if you knew the series from PSX then you know this game.
Too bad the server closed in 2008 :(