Network operators around the world are moving their infrastructures to the cloud to gain flexibility, speed up service deployment and make their operations more efficient. But many stop short at the session border controller (SBC). They wonder if it’s really possible to virtualize such a complex and critical piece of hardware, especially with Voice over LTE and Voice over WiFi pushing demand for SBCs through the roof.
The fact is, SBCs can be virtualized — and moved into the cloud. But there are three key questions to answer first:
1. What about the signaling and media planes?
In hardware SBCs, the signaling and media planes are often tightly intertwined, making it impossible to reap core benefits of virtualization like resource optimization. Fortunately, this can be overcome by decomposing the two planes and packaging virtualized network function components into virtual machines that can scale independently to meet fluctuating traffic profiles and demands.
2. Can media quality be controlled?
SBC input/output (I/O) requirements are undeniably huge, and operators want to be sure any virtualized SBC will deliver the same quality of service as a physical appliance. That means handling transcoding and encryption along with, say, seven to 10 control packets and 20,000 real-time transfer protocol (RTP) packets for a typical three-minute VoLTE call.
Beyond volume there’s the question of complexity. With a physical SBC, RTP (or media) packets pass through the data/forwarding plane only. In a cloud environment, they go through multiple layers — including the hardware resources layer and the virtualization layer — as well as inter-process communication interfaces before even touching the application. Those additional checkpoints can significantly impact the achievable system throughput and packet rates.
These concerns about media quality can be addressed, in part by using a virtualized infrastructure manager such as OpenStack to smartly configure the virtualization layer for optimal system performance. Also required is a combination of advanced technologies to accelerate the media plane, such as single-root I/O virtualization (SR-iOV) and the data plane development kit (DPDK).
3. Is it compatible with the MANO framework?
It can be tricky to integrate a virtualized SBC with a cloud-based management and orchestration (MANO) framework to automate operational processes for managing application lifecycles from deployment to phase out. This is especially true in a multivendor cloud environment where the network functions virtualization orchestrator, virtualized network functions manager and virtualized infrastructure manager may all be built by different suppliers. Finding a way around this challenge to gain operational efficiency and lower expenses through automation requires a solution that will work with any customized MANO framework.
Nokia Cloud SBC migration approach
Nokia has developed a virtualized SBC that supports independent media and signaling plane processing at scale, optimized media performance and simplified lifecycle management. The software is designed to deliver the access and peering functions operators need to support their IP multimedia subsystem (IMS) networks — and can be deployed on-site in integrated 2 x 2U form or fully in the cloud. Nokia’s IMS portfolio is ranked as a leader in the market by Current Analysis, with border control offerings in the top range of their product class average.
For more on migrating SBCs to the cloud, watch the “Migrating Session Border Controllers to the Cloud” webinar, co-presented by Nokia and IHS Markit. Also check out IHS Markit’s accompanying report, which you can download here.
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