 performed to authenticate the subscriber and to secure the communication channel. 3. Location update is done by the MME to the HSS to record the UE's location in the subscriber database. 4. Create Session Request message is sent from the MME to the SGW to begin the establishing of the default EPS Bearer. The SGW creates a new entry for this bearer in its EPS Bearer Table, and sends the message to PGW to establish the bearer at the PGW. 5. Create Session Response is sent as the response to the Create Session Request, indi- cating the success or failure of the bearer establishment. In case of success, the PGW creates an entry to its EPS Bearer table, and it allocates the IP address or addresses for the bearer. The PGW sends the message to the SGW, which sends it forward to the MME. The message includes the IPv4 and/or IPv6 address allocated to the UE, and the additional PCO needed to configure the IP stack of the UE. 6. Attach Accept message is sent to the eNodeB to indicate successful attachment to the network. This message includes the address or addresses and the PCO included in the previous step. 7. Radio Resource Control (RRC) Connection Reconfiguration procedure configures the Radio Resources and provides the IP address, and PCO information to the UE. 8. Initial Context Response is sent to the MME by the eNodeB to inform the MME of the eNodeB's address. This message and the Attach Complete message can also be sent in a different order to the MME. 9. Attach Complete message indicates that the UE has finished the attach and the default EPS Bearer setup. At this point, the UE can start sending user layer packets. 10. Bearer Modification procedure is performed between the MME and the SGW upon the MME receiving both Initial Context Response and the Attach Complete messages. The Bearer Modification procedure provides the eNodeB address to the SGW, which allows the SGW to start forwarding IP packets towards the UE. 11. The attach and default EPS Bearer establishment procedures are complete, and the IP packets can f