What network is saturated - the pipe from the application to the clients, or any of the links between servlet container/ejb container/database?
If it's the pipe to the clients, what is saturating it? Do you have any huge images? Then get rid of them, or reduce their size e.g. by using appropriate formats or lowering jpeg Q factors. Or is your generated HTML particularly huge? In that case add a servlet filter that performs HTTP response compression if the client supports it (after we put that in place, premierleague.com pages shrank to 10% of their original size, halving total bandwidth useage). Also, if you can, make sure you set sensible Last-Modified headers and so on so that a browser or proxy won't download a page that didn't change (eg If-Modified-Since).