Although not an answer to your question, what type of connection do you have? The reason I ask, even if you invest time, and money to answer your above questions, unless you have a high end service (ds3 or above), depending on what your SLA states, your ISP may not care.
Also, if the issue is outside your ISP's network, IE a backbone provider, again, it would be out of your ISP's hands.
Taking your 10 seconds in a 120 minute span example, even if that happened every 120 minutes, which It sounds like it is more random. But for example proposes, you are only talking about a total of 2 minutes of down time every 24 hours, or 99.86% up time, which although is annoying, probably comes close to meeting your SLA.
So in short, what type of service do you have, and what does your SLA state? My point is, it may be a better use of your time to find another ISP option, then to try and bang your hand against the wall with your current provider.--
Lightning Bolt Technologies