Interconnection points are by definition part of two networks. The question is whether the congested interconnect involves Verizon at all. I would hope that, before writing this letter, Mr. Hyman would have done his research and verified that it is indeed an interconnect that Verizon is involved with. However, it is an unanswered question.
I'm sure Netflix is carefully choosing every word, well beyond one person's responsibility. This is fire they are playing with, and they know it. They're probably treating this like a legal brief that will end up in court before a judge, because the odds of that actually happening are pretty good.
It is not an unanswered question, it is merely a question you personally have not bothered researching properly. Network engineers have thoroughly answered this question.
Heck, even I write mails to my ISP and tell them which interconnect points they're having issues at which a simple traceroute/mtr show me. And I mostly get positive feedback.
With a bit more sophisticated tools, you'll get more confidence. Or if you're Netflix, I'd assume you can just call up level3, ask them to resolve the transit issues you're having with Verizon, and get feedback and reports about it being verizon not upgrading their interconnect to level3. I'd not be terribly surprised if verizon is one of the 6 peers mentioned at http://blog.level3.com/global-connectivity/observations-inte...
Traceroutes from a single source are poor tools for positively determining a source of latency. A traceroute only tells a unidirectional story, and an incomplete one at that.
In reality in is essential to use multiple provider/observer based tools to determine point(s) of congestion. However, it is entirely possible to empirically determine who the congested peers are between, which, and when specific geographical connections are overloaded.
