There is an issue with network hardware driven by the atl1e driver under Fedora 11 that consistently causes network traffic corruption. Such hardware includes, at least, some ASUS motherboards, newer eeePC models, and some hardware from Acer. Where a different network card cannot be added, users who depend on reliable network traffic would be advised to not upgrade from Fedora 10 to Fedora 11 at this time. This issue is being tracked in bz 503288.
Added to hardware section of zero day release notes