Nortel Networks Nortel Networks With the advent of Content Delivery Networks and personalized services there is a need to uniquely identify a user in oder to be able to offer customized services and content. Unfortunately, the IP Internet makes personalizing content and services difficult for the providers. With the virtualization of Web resources and the widespread use of proxies, an IP address no longer uniquely identifies a Web user or destination. So in oder to uniquely identify a user, the service provider has to make the identification on the edge (or access) network, before the user looses his identity in the core of the network. We present here a overview of these techniques available on the different types of access networks.