A very good post from http://community.lcnpl.com/68/virtual-epc-a-technology-demonstrator
Network Function Virtualization has been accepted as a game changer by Service Providers. Initial excitement has given way to working POCs. Many industry bodies like ETSI, 3GPP and TMF have been working on standardizing various aspects of the technology.
In a mobile network, certain components of the packet core are ideal candidates for virtualiztion. PCRF, Online Charging Function (OCS) and HSS are compute intensive, and need to scale up as the load increases. Further, since they are part of the control plane, they are easier to isolate and move to a private cloud – or even to a public cloud.
LCN with its focus on the signalling in the packet core, has developed a Proof-Of-Concept Virtual EPC. The components are,
• Virtualized prototype PCRF built with LCN Diameter stack and Gx APIs.
• LCN Diameter Signalling Router capable of handling dynamic changes to the forwarding table.
• OpenStack integration layer that taps in to OpenStack notifications.
• Sample PCEFs built with LCN Diameter stack, sitting outside the cloud.
In the above configuration, multiple PCRFs are running within the OpenStack cloud as virtual machines. LCN Cloud Monitor is an application running on the control node, listening to various OpenStack notifications and acting on specific events. The DSR is running outside the cloud, closer to the devices. But all these entities can also be moved to the cloud as needed.