if u are using ADSL (singnet or pacnet), you might check the
quality of your filter or your house phone (spoiled house phone)
could affect your broadband line. That was the case for me
when for a few days my internet keep dc-ing. Then i realise one of
my house phone spoiled, i replaced it and everything is working
fine again.
He's using starhub though.
For sudden loss of internet connection, it can be your cable
that causing the problem, if thats the case call someone down from
starhub to check it out. If not, the problem lies with either the
router or the modem. Pick one.
I have that problem before (though I'm a singnet user), I just
changed my router and poof, the problem is solved. Fking MIO
router, the only thing I like is the strong signal strength.
For the lag, I don't think anyone can help. One possible answers
is there are too many people at your area using starhub, don't
forget it's one fat green pipe but shared. If what I said is true,
too bad you've got to suck it up and switch provider when your
contract ends.
Btw, what you tried opening ports on your router? Some modem
have build-in NAT and firewall too, do check it out.