If the disconnect error you're getting is

Internal Exception: io.netty.handler.timeout.ReadTimeoutException

then this is a known bug in 1.7.2 that seems to be triggered in a variety of situations. (The 1.7 update brought entirely new networking code, and this is one of the downsides of brand-new code.)

On our server we've also been encountering this issue while out exploring new chunks. It has been frustrating not to be able to explore freely without disconnecting and affecting everyone else on the server. This error happens even if you are the only person online. Faster connections and allocating more RAM to the server doesn't fix a thing. It doesn't mean your sever is underpowered.

Here is the current open bug report for this issue. Keep an eye on that, and hopefully it will be solved for the next update.