Timeout error in 1.7.4 multiplayer

Between 1 and 5 minutes into any multiplayer game, the error
''Internal exception: io.netty.handler.timeout.readTimeoutexception" comes up and I am booted from the server. This happens on any multiplayer server I join, and started happening last week. My Internet connection is very good, and I have reset my router, re-installed vanilla Minecraft 1.7.4, etc.