What is EPC and IMS?
First of all there is the Evolved Packet Core (EPC) and then there is the IP Multimedia Sub-system (IMS), as shown in Figure 3.15. All user data goes through EPC and the data related to the operator IMS services (such Voice over LTE) goes also via IMS while traffic to the normal internet does not.
What is EPC in telecom?
Evolved Packet Core (EPC) is a framework for providing converged voice and data on a 4G Long-Term Evolution (LTE) network. 2G and 3G network architectures process and switch voice and data through two separate sub-domains: circuit-switched (CS) for voice and packet-switched (PS) for data.
Which node is used in IMS and EPC network?
Nodes
| Node Abbreviation | Full Name | Applicable Network |
|---|---|---|
| HLR | Home Location Register | GSM,GPRS,UMTS |
| HSS | Home Subscriber Server | EPC,IMS/VoLTE |
| IBCF | Interconnection Border Control Function | IMS/VoLTE |
| I-CSCF | Interrogating CSCF | IMS/VoLTE |
What is LTE HSS?
Home Subscriber Server (HSS) is the main subscriber database used within the IP Multimedia Subsystem (IMS) which provides details of the subscribers to other entities within the network. The IMS enables users to be granted or refused access to other services dependent on their status.
What is SLF in IMS?
The subscriber location function, or SLF is a function within an IP multimedia subsystem that provides information about the home subscriber server (HSS) that is associated with a particular user profile. It is generally implemented using a database.
What is IMS EPC in LTE?
The idea of IMS is old, but after it’s deployment with LTE users and operators can harness the true power of IMS. IMS – IP Multimedia Subsystem is a standalone system. It resides out of the LTE network and connected to PDN Gateway through SGi interface. The EPC has three main functional elements.
How does the EPC work?
It resides out of the LTE network and connected to PDN Gateway through SGi interface. The EPC has three main functional elements. The first one is Mobility Management Entity (MME). MME is the single most control point in the EPC and responsible for most of the control plane functions.
What is the difference between a UE and an IMS powered UE?
P-GW allocates IP addresses to UEs. It also provides interfaces towards internet and IMS. The following architecture diagram shows EPC, IMS and the interface between them. UE is a mobile terminal authorized to be used in an LTE network. UE may be a smartphone, tablet or other communication devices. An IMS powered UE has two main components.
What is the role of Mme in the EPC?
MME is the single most control point in the EPC and responsible for most of the control plane functions. The second in the list is Serving Gateway (S-GW). All IP packets in uplink and downlink flow through S-GW. S-GW is also responsible for handling handovers. The last in the list is P-GW or PDN Gateway. P-GW allocates IP addresses to UEs.