Mobile network operators have taken the first important step of centralised/cloudified RAN (C-RAN), for the ultimate goal of 5G Network Slicing. While C- RAN is critical for the transformation of 4G mobile networks to 5G networks, many 4G operators are adopting the technology earlier i.e., at the same time as their packet core networks are being virtualised.
There are several reasons for this early adoption, says Cyril Doussau, VP – Service Assurance Strategy at InfoVista. CSPs consider the deployment of C-RAN critical for the launch of new high reliability and low latency services such as autonomous cars, robotic applications and numerous IoT services. But the most critical aspect of the early adoption is that C-RAN brings about a transport network revolution, which requires a high level of end-to-end management before it can deliver the results.
5G transport network to support high QoS services
High throughput, dynamic bandwidth allocation, high reliability and low latency and are the key benefits that mobile operators expect from the 5G C-RAN and the virtualised core networks.
5G services that are being designed depend heavily on these capabilities of the network. While high throughput and low latency will support upload and download of video-based content faster, dynamic bandwidth allocation supports various location-based video services. With high reliability capabilities, 5G networks will support services relying on high connectivity such as driverless cars and commercial drones, as well as the many millions of IoT devices.
A significant overhaul of the underlying transport network is being undertaken by CSPs to support these high 5G QoS requirements. The new 5G transport network will function very differently from the 4G transport network. Not only does it need to support the low latency, high throughput, high reliability of data, it needs to be managed far more in real-time to offer the guaranteed service for each of its 5G network slices.
With the introduction of a high-QoS Fronthaul transport network, a centralised (and ultimately cloudified) Baseband Unit (BBU), traffic orchestration of RRH (Remote Radio Head), many of these requirements are achievable. The new transport protocols (CPRI/eCPRI) that will run on the Fronthaul transport network will help to reduce packet size, transmission time and propagation time to as low as possible, ensuring that 5G delivers the following QoS:
- Throughput of 10-20 Gbps
- End-to-end latency of 1-10 ms
- Jitter of 10-100 microseconds
5G SLAs require E2E Transport Service Assurance
SLAs will dynamically govern the quality of services delivered through the 5G network slices. And in most cases, the commercial agreements for quality parameters will be very demanding, given the mission-critical nature of services that will be delivered over the slices.
Auto-scaling to support dynamic SLAs is a technique unique to 5G that helps in achieving such QoS guarantees. This translates into slicing of 5G network functions (C-RAN and Core) such that network and service resources can be auto-scaled dynamically. However, not just the network, but its allied ecosystem also has a hand to play in supporting this. Specifically, the network orchestrator and the Service Assurance solution.
While the main responsibility to assure latency, reliability and connectivity lies with the 5G operator, Service Assurance solutions are needed to extend assurance to the slices and their constituent components: Core, RAN and, most essentially, transport. Only then will the sliced 5G network be technically and commercially successful, and deliver against the SLAs.
Orchestrating the network for 5G SLAs requires experience with the industry verticals and enterprises, and a constant vigil of the SLA parameters. Unless the Service Assurance solution reports in real-time, and offers support to the network orchestrators in real-time, the concept of dynamic SLAs for the industry verticals will fail.
To prepare the CSP for the above-mentioned challenges of the 5G transport network, a real-time and dynamic Service Assurance solution can immediately address some of the challenges as the networks evolve from 4G to 5G. This includes management of the performance and capacity of the BBU and RRH links, management of the transport network’s high-QoS fronthaul, and ensuring that the mobile backhaul delivers a higher QoS for 5G compared to 4G.
The author of this blog is Cyril Doussau, VP – Service Assurance Strategy at InfoVista.
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