In Vietnam, possible to have 2 different I.SP's at the same address?

Yes, it is possible, provided you have access to two different I.S.P.s in your location. When I first moved to the apartment I'm in now 5 years ago, I ran two I.S.P.s at the same time for one month so I could see which one performed better. After that time, I chose the better one. The only problem you'll have is the wiring. If using ADSL, you'll have to make sure the different providers don't try to use the same two conductors in your 4 conductor phone wire. Get that sorted and it's no problem.

Thanks for the info. I'm based in Nha Trang so I guess I need to know which companies operate here and are they designated geographical areas for their sole coverage? I have a feeling they are, as an ex-pat I was chatting with was talking of moving to a different area and one of the benefits of that area was that the I.S.P was better. Does anybody know if this is the case in Nha Trang?