In this second chapter of the book we will take a closer look at the signaling procedures across the wired or fibered transport links of the E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and the EPC (Evolved Packet Core) network. This will give some insight into the details of session and bearer management. Also, it will be explained how the mobile communicates with the network on the Non-Access Stratum (NAS) layer that is responsible for subscriber registration and macro-mobility.
Also in this chapter the signaling procedures on the S1 interface between eNodeB (eNB) and the MME Mobility Management Entity, on S6a between the MME and Home Subscriber Server (HSS), on S11 between the MME and Serving Gateway (S-GW), and on the S5 reference point between S-GW and the packet data network gateway (PDN-GW) will be discussed in detail. This will also provide insight into how the user plane packets are tunneled and routed through the EPC network.
2.1 S1 Setup
The S1 Application Part (S1AP) S1 setup procedure is used to take a new eNB into service. Basically this is the same functionality as the NodeB setup on the Iub interface of 3G Universal Terrestrial Radio Access Network (UTRAN). However, in comparison to the Iub signaling procedure, S1 Setup is simpler. And S1 Setup is directly triggered by the eNB while the 3G NodeB only requests to be audited by the RNC. This means that in the 3G UTRAN the RNC is the master of all NodeB configuration parameters, ...