n "Some of the dynamic price work assumes that users can choose routes. n In fact, in today's internet, routes are pretty much fixed by ISPs. n At each level there exists a highly structured market of access, transit and core ISPs with rules and so on. n Users can select access routes only by dialing different ISPs, or on a slower timescale (timescale is the critical question) can pay to have DSL, cable modem or other links installed by other ISPs.