Concern about print buffers on printservers and jet direct cards - won't they get overrun

Here is the issue, I have a situation where the customer has been using serial and parallel communications only with various print devices (laser, dot matrix, etc).  Handshaking in these protocols has allowed their accounting software to spool jobs of several hundred pages in length without issue.  As much as possible they will be converted to a networking backbone - for some of the serial printers we will use digi ts/4, however for the parallel and new usb printers we are considering using print servers and perhaps printers with jetdirect cards.  Now, all of these devices, (including the digi port server) have limited buffer space.  Considering warm up times on printers, etc how likely is this to be a problem when large print jobs are being sent.  It seems to me that 10mb network speeds will quickly overlfow the buffers - especially if the printer is offline because operator is loading/adjusting forms or laser is going through a warm up cycle.  Their software provider prefers not to have any printers connected through pc's to keep things simpler.  In the "good old days" everything used handshaking for serial or line control for parallel and so this was never an issue.  Print servers etc are used so extensively nowdays that I assume that this is really not a problem or one that has been solved in some easy fashion.  However my "If I don't understand it I don't like to do it" keeps me from just saying ok and moving on.