I've attached a 12 hr snapshot. What gets me is that my connection goes down every 30 minutes almost like clockwork, save for a few occasions.

Comcast goes down in this area every week.. but I can't help wonder if this problem could be something on my network, I'm not sure. It's a really big network, strewn with dozens of random, un-monitored wireless routers and switches. The network is also considerably old (20+ years?), I've considered replacing all the patch cables and recrimping the uplinks just to be thorough.

Any ideas if this is me or my ISP? Any comments at all are appreciated.