Xbox live disconnects randomly and for like 1 second why?

i didnt start having problems with this until like 4 months ago and i didnt change any network settings routers modems..nothing changed it only disconnects me for like 1 second but thats long enough for it to kick me out of anyonline match im in...and i watch my modem it never shows any problems and my network latency doesnt spike b4 or after it does it...so im aat a loss...and and xbox support says its my modem dsl says its xbox live...lol