Core network virtualization
Network operators are virtualizing their core networks in an effort to gain a competitive edge in the marketplace. By enabling virtualization in the core network, service providers can significantly decrease operational expenditure (OPEX) and capital expenditure (CAPEX), while accelerating the delivery of customizable services. This article explores the technologies that can be used to virtualize the core network.
What is a core network?
A core network is the control center of a telecom network, which provides different services to customers interconnected through the access network. Its general purpose is to provide an optimal path for the exchange of information among various sub-networks. Typical core network features include aggregation, authentication, call control or switching, charging, gateways and service invocation.
NFV
Core network virtualization can be achieved by leveraging network functions virtualization (NFV) technology, which has played a major role in reshaping telecom equipment. The process involves decoupling software from hardware, and performing network functions like firewall and encryption on virtual machines (VMs). These VMs run on inexpensive nodes, which network administrators can use to set up a service chain of network-connected devices. Whenever a customer requests a network function to be installed or updated, for instance, the service provider can spin up a VM that performs the desired function automatically using a mix of switches, storage and servers.
SDN
Software-defined networking (SDN) can help virtualize the core network as well. It serves as an architecture that enables network behavior to be centrally controlled using application program interfaces (APIs), or open programmatic interfaces like OpenFlow. The technology can help simplify the core network, while providing a greater amount of flexibility.
The basic idea behind SDN is to separate network control functions, the control plane, from data forwarding devices, the data plane. Control plane capabilities are implemented by a SDN controller. A network administrator can program the SDN controller to address different needs and update the network automatically to support changes. For example, whenever a packet of data arrives at a switch, and the switch is unsure about how to process the packet, it can wait to receive instructions from the SDN controller. Based upon protocols made by the network administrator, the SDN controller can then determine whether or not the switch processes the packet.
Network slicing
Network slicing is another core enabling technology, which leverages both the principles of NFV and SDN. With network slicing, network operators can divide a single, physical network into various virtual networks, with each slice representing an independent, virtualized end-to-end network. In the core network, both NFV and SDN can be used to virtualize network components of each slice to meet specific customer needs. With the commercialization of 5G approaching, many network operators intend to use network slicing to partition the 5G core network.
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