t - that is, manage the connections between the UE and the network - and what technologies are used to actually move the end user's packets back and forth over the network. However, it might not be quite clear how all of these work together, and how certain things are decided in the network. In this section, we try to add a bit of information to pull some of the concepts together. 2.5.1 PDP Contexts and EPS Bearers We have gone through the different procedures of session management - on how to activate, modify, and deactivate PDP Contexts and EPS Bearers. We have said that these are the connections that connect the UE to the network. In this section, we will look at these connections, their characteristics, and the relationship of the different PDP Contexts and EPS Bearers to each other. First of all, conceptually the PDP Contexts and the EPS Bearers are very similar, or even the same. They are connections that extend from the UE to the network gateway - the GGSN or the PGW. To send and receive packets, the UE needs a connection to the gateway. This gateway will then provide the UE its IP address. The UE will use this IP address to send and receive traffic on that particular connection. That connection is in GPRS a PDP Context, and in EPS architecture it is the EPS Bearer. The packets sent or received on this connection will all be treated the same way - they will all be put in the same packet queue and treated in first-in-first-out manner. A PDN Connection can be used as a synonym for an EPS Bearer and PDP Context when there is no need to differentiate between dedicated bearers or Secondary contexts, just to refer to the IP level connectivity. The PDN Connection is the association between a UE and a PDN represented by an Access Point Name (APN) and the associated IP level configuration. Multiple Connections to One Network If there is a need to provide a different level of service for different IP packets, another connection needs to be opened - a Secondary PDP Context in GPRS as described in Figure 2.13, or a de