low in both directions. Comparing the two connection establishment procedures in Figure 2.14 and in Figure 2.13 may make the GPRS PDP Context activation procedure look simpler. However, this is not completely true as the GPRS PDP Context activation in Figure 2.13 does not include the network attach procedure. In GPRS, the network attachment also has to happen before PDP Context activation can be performed. In addition to the default bearer establishment, additional connections can also be created. These are called dedicated bearers. The dedicated bearers are similar to the Secondary PDP Contexts in GPRS. They provide, for instance, additional QoS capabilities to the communication. The dedicated bearer activation procedure is shown in Figure 2.15, and each related message is described below. Basics of the 3GPP Technologies eNodeB 1. Request Bearer Resource Modification 2. Bearer Resource Command 3. Create Bearer Request 4. Bearer Setup Request 5. RRC Connection Reconfiguration 6. Bearer Setup Response 7. Session management response 5. Create Session Response 11. IP trafic Figure 2.15 Dedicated EPS Bearer establishment. 1. Request Bearer Resource Modification is sent by the UE to the MME indicating the request for a dedicated bearer. 2. Bearer Resource Command is sent by the MME to the SGW. The SGW sends the Bearer Resource Command to the PGW; if it is accepted it triggers the Dedicated Bearer Activation process. 3. Create Bearer Request is sent from the PGW via the SGW to the MME, indicating the creation of a dedicated bearer. The message contains the information about the characteristics of the bearer including QoS and PCO parameters. 4. Bearer Setup Request/Session Management Request is created by the MME with the information received from the SGW in the Create Bearer Request. The MME sends to Bearer Setup Request to the eNodeB. The Bearer Setup Request is a message between the MME and the eNodeB. It contains information for creating the Session Management Request, which is sent from the MME and to the UE, but t