As service providers plan their networks and make strategic technology choices \u2013 like fiber to the home vs. fiber to the node vs. enhanced CO DSL \u2013 they rely upon certain assumptions about how customers will want to use bandwidth, and what sorts of bandwidth requirements customers will have, and \u2013 most importantly \u2013 what minimum requirements users will seek from their provider (or go to another provider for).The orthodoxy here is that certain applications like telco TV will use the majority of bandwidth provided to network customers, and that this bandwidth will be relatively predictable. The major U.S. telcos (Verizon and AT&T) are in the midst of massive network buildouts that are based on this assumption.Likewise, there continues to be an assumption that customers will be consumers of bandwidth, and that an asymmetric skew towards downstream bandwidth is the right model. In the U.S., both FTTH and FTTN\/VDSL deployments are being built around this assumption.And at a high level view, these assumptions seem to be pretty correct. After all, TV is the biggest bandwidth consumer in the models that telcos use for these decisions. And TV does, at first glance, appear to be a predictable (and primarily downstream) application.The monkey wrenches that most good models account for are peer-to-peer applications (like Bit Torrent), and other video services that bypass the telco TV offerings (like Google Video, Movielink and Apple\u2019s iTunes Music Store). Most model builders and analysts understand the gigantic impact that these apps have on the network \u2013 particularly peer-to-peer today, but also the emerging impact of entertainment bypass services like those mentioned.But we\u2019ve seen some evidence recently \u2013 most notably in a Japanese research study conducted by IIJ Research Lab (Internet Initiative Japan) \u2013 that makes us think that most folks in the service provider community have underestimated the impact of these services. That\u2019s because most folks believe that the massive impact of peer-to-peer on their networks is caused by a handful of \u201cbandwidth hogs\u201d who spend all of their time grabbing the latest high def torrents of Lost and 24, and then reseeding them back to other peer-to-peer users.What the Japanese study, which was based on observation of over 4 million FTTH as well as DSL customers in the country, showed was that these high bandwidth consumers (called \u201cheavy hitters\u201d in the study) were not relegated to just a small subset of users. There was, in other words, no distinct user segmentation or demographic that defined the heavy hitters using P2P and other bandwidth intensive entertainment services on their FTTH connections.Instead, these users tended to be distributed across all segments of the FTTH customer base. Some, according to the study, are users of P2P and other services who move to FTTH for the increased performance it gives them, but others are more casual users who upgrade to FTTH and then \u201clook for applications to use the abundant bandwidth.\u201dIn the Japanese study, the heavy hitters were still a small-ish segment of the overall user base (4% of users accounted for over 60% of the bandwidth consumed), but the usage trends of these users were not significantly different than those of more casual users. In fact the analysis found no clear boundaries between heavy hitters and normal customers \u2013 meaning anyone can become a heavy hitter, and probably will as peer-to-peer and entertainment bypass applications become more mainstream.The takeaway we see here is the old Field of Dreams quote: build it and they will come. The only thing that really stood out about the heavy hitters was the fact that they were much more likely to be found amongst FTTH users \u2013 rather than DSL users. When users got access to higher bandwidth, they used it. When they got access to symmetric bandwidth, they used it symmetrically.The bottom line is that it\u2019s not just a handful of hardcore file sharers who can end up impacting your network and using tons of bandwidth. It can \u2013 and probably will \u2013 be any of your users. The use of bandwidth-intensive peer-to-peer and entertainment apps isn\u2019t going to slow down any time soon, so you\u2019d better have a plan to support and monetize these apps.