I read all the posts on this site on IXP's and my question remains. Any clarity that anyone can bring to this topic would be much appreciated.
I have trying to get a better mental big-picture of how the internet works I stumbled across the Wikipedia article about Tier 1 networks that really helped build my picture. This lead to Wikipedia'ing about interconnect agreements and especially internet exchange points which helped to greatly clarify the mechanisms of the internet. I found www.internetexchangemap.com which helped with a physical picture.
I was then curious which tier 1 networks participate in my local IX, the Milwaukee Internet Exchange, but to my surprise I did not recognize any of the networks listed - no Verizon, AT&T, Sprint, Time Warner, although Verizon, AT&T, and Sprint are listed as Tier 1 Networks on Wikipedia. I also checked the Chicago Exchange Point and found the same. I looked up most of the companies that are listed; some were very small ISP’s. But if it is not these major ISP's (Verizon, AT&T, Sprint, Time Warner) that converge at Internet Exchange Points, then I feel there may still be a little infrastructure involved that I do not understand, like a hand off between these major ISP's and some more obscure major networks that don't deal with consumers. If not at these major IXP’s, then how does an AT&T end user request make it to a web server on a Verizon network?
A related question: I'm also wondering what the Milwaukee Internet Exchange means in their FAQ when they discuss how you can go there and "connect" (www.mkeix.net/faq/).