This illustration uses a series of ovals and squares to illustrate the interconnectivity between ISPs. At the top are three large gray ovals; from left to right they are labeled: "Tier 1 ISP," "Tier 1 ISP," and "Content provider (e.g., Google)." Beneath these are three gray squares; these are each labeled "IXP." Beneath these are two medium blue ovals, each labeled "Regional ISP." Beneath these are a series of eight small blue ovals, each labeled "access ISP." All of these shapes are linked to each other through a network of black lines: The Tier 1 ISPs are connected to each other and to the Content Provider; they are connected directly to the access ISP, and they connect to the IXP, which connects to the Regional ISP, which also connects to the access ISP. The Content Provider connects with the Tier 1 ISPs; it connects to the access ISP directly, and it connects with the IXP, which connects to the Regional ISP, which also connects to the access ISP.