OpenEPC Rel. 2 - General Considerations

OpenEPC Rel. 3 components are targeted at offering an affordable and self-contained environment for starting testbed experimentation of the Evolved Packet Core. The different functional parts have been realized as much as possible in the spirit of the 3GPP EPC standards available currently as part of Release 10. However, as a specification-conforming implementation would be impossible to achieve within our limited testbed prototyping targets, while also the EPC concepts being relatively new and quite dynamic in the standardization bodies, the OpenEPC Rel. 3 can not claim full-support of all the 3GPP release specifications.

Featuring all the components of the 3GPP EPC standard, with more than 15 different and mostly new functions and components, its complexity should not be regarded as trivial. In order to provide prototyping agility, new component frameworks have been developed as part of the OpenEPC toolkit. Together with the components, fully featured configuration and provisioning data as well as installation, how-to guides and even source code documentation can be bundled. This will provide you with an easy learning curve, even if you do not have any previous EPC knowledge, using OpenEPC toolkit an functional reference.

Functionality-wise, the OpenEPC Rel. 3 features can be categorized as:

1. Core Network Mobility Management - OpenEPC includes two integrated core network mobility management options one through GTPv2 and one through Proxy Mobile IP. The functionality of the mobility management is deployed on the gateways as well on the eNodeB and 3GPP NodeB emulator and on the MME and SGSN components. It allows transparent IP connectivity to the devices and applications and zero packet loss handovers between 3GPP and non-3GPP access networks

Novel with Rel. 3 new routing modules were introduced for the data path entities, enabling flexible data forwarding and performance improvements related to mobility management support.

2. Core Network Support for LTE Access - OpenEPC includes its own implementation of the MME and core network part of eNodeB (without the radio part) enabling the easy showcasing of scenarios using the LTE access network. This includes the attachment procedures to the LTE access network including the security procedures through the HSS. Furthermore, OpenEPC includes the procedures for the default and the dedicated bearer reservations according to the requirements of communication of various mobile subscribers.

New with OpenEPC Rel. 3, the NAS and GTP stacks were completed with full standard support and the S1AP supports Aligned-Packet-Encoding-Rules. The X2AP and the X2 interfaces were newly introduced.

3. Core Network Support for Other 3GPP Accesses - The OpenEPC includes the core network support for the 3GPP accesses consists of an SGSN implementation and a NodeB simulation which emulates the specific characteristics through a generic RAN over WiFi? technology.

4. AAA for non-3GPP Accesses - OpenEPC Rel. 3 sustains the authentication and the authorization of the subscribers for both the trusted and non-trusted non-3GPP access networks. It enables the showcasing of full connectivity establishment procedures according to the non-3GPP accesses integration specification. The non-3GPP AAA functionality relies on the OpenEPC AAA Server, which is able to communicate via DIAMETER with the HSS and with access and data path specific entities.

5. Policy and Charging Control - OpenEPC implements all the PCC components and a major set of the functionality. The PCC enables policy based access control, gating and QoS and charging control as well as notification for data path events based on the subscription profile of the users. The functionality of PCC is easily integrated with the OpenEPC Core Network Mobility Enablers. Through its Rx enabler, OpenEPC enables practical show-casing of various services and service platforms in heterogeneous environments.

OpenEPC Rel. 3 includes an overhauled set of components which handle the data traffic in the data path gateways enabling flexible routing. This functionally lead to high performance improvement as well as to a high flexibility support for gating and QoS throttling. Additionally, as the data traffic handling is completely controlled by the OpenEPC components, traffic counters and monitoring functionality is sustained.

6. Offline Charging System - OpenEPC Rel. 3 includes the novel Offline Charging System enabling the demonstration of complex accounting, charging and billing scenarios over the OpenEPC, service platforms such as IMS and applications by combining session based with event based information correlation. Through monitoring and differentiated accounting for sessions and events at core network, service platform and at application level as well as the orchestration of the charging information into single billing information.

7. Subscription Management - OpenEPC includes a single subscription repository named HSS which includes the functionality of the Home Subscriber Server (HSS) and of the Subscription Profile Repository (SPR) from the 3GPP EPC. The OpenEPC HSS includes the interfaces towards the 3GPP access network control entities - S6a to MME and S6d to SGSN - enabling the authentication and the authorization of access over these radio technologies. Additionally, it includes interface towards the AAA Server, enabling authentication and authorization to non-3GPP accesses. As SPR, the HSS provides through the Sp interface subscription information enabling PCRF and ANDSF policy decisions. Furthermore, it provides subscription information towards IMS core and Application Servers, supporting unified subscription data for core and service platform.

8. AAA Signaling Routing - OpenEPC features a Fraunhofer implementation of a DIAMETER routing entity, generically named Service Locator Function (SLF) which mitigates the control distribution gap. Inspired by the application level routing, the OpenEPC SLF proxies the DIAMETER sessions between the requester which may be a data path entity such as a PDN GW selecting the PCRF or a control entity such as the MME, SGSN or PCRF selecting an HSS entity.

9. Client Mobility Support - OpenEPC enables policy based access network discovery and selection in the heterogeneous wireless environment, through its ANDSF component which features built-in policy engines and has support for both Access Network Discovery Information and Inter-System Mobility Policies, such that new ABC concepts can be prototyped and trialled. The Client Mobility Manager provides the abstraction layer on the client devices, such that the EPC handover mechanisms and policies can be show-cased independent or enhancing the applications together with features such as location, link layer quality measurements etc. This Client Mobility Manager exports an open API, illustrated by an open source Mobility Manager GUI, which provides the integration point with mobile frameworks and application.

10. Additional EPC Demonstration Enablers and Protocol Stacks - For demonstration purposes, OpenEPC provides application enablers such as HTTP-Interceptor with EPC adaptor, and protocol stacks like for DIAMETER, Radius, GTPv2, PMIP, S1AP, X2AP, NAS. OpenEPC targets to provide a comprehensive setup, which can be show-cased out of the box. As such, additional components, scripts and extensions are provided. Starting from Rel. 2 OpenEPC includes a new tool for visualization of the communication inside the network operator enabling a better perception of the real-time demonstration scenarios and message exchanges in the core network.

The first three releases of the OpenEPC toolkit established an aggressive roadmap, which targets major releases at every 9 months, with new feature previews at every 3 months. Technical support, bug-fixing and new features can be provided either at a best-effort level or as additional support-bundles and R&D project on topics of your requirements. Please note that the current roadmap is not written in stone, but would rather be driven by direct requests. In case that you are interested in a feature which is not currently supported, please contact us and indicate your use-case scenarios, budget and time-plans, such that the relevant functionality would be prioritized.

OpenEPC can be licensed in a flexible manner. The available options range from binaries only to source-code which could be embedded directly into commercial components. For academic partners OpenEPC is offered at a discounted price. Customers can also choose between complete setups and functionality subsets. Minor and preview upgrades are included, while major releases are discounted for existing customers. Best-effort support is offered for free and additional technical support bundles are available on requests. New features, components and reference points are to be developed under the umbrella of R&D projects.