Core vs. Edge in 5G

Release Date:2018-08-16  Author:By Tommy Bjorkberg  Click:


At MWC 2018, I had the honor to participate in a panel discussion titled “Do 5G Business Cases Depend More on Core or Edge Upgrades”. The panel featured an impressive group of representatives from across the global telecom industry who were split into teams to advocate one side over another. I was a proud member of “Team Core,” and focused on the importance of a 5G core in terms of its ability to deliver, tailored “slices” of the network to enterprise customers, offering significant growth prospects for network operators offering connected services such as IoT and M2M. Although it was a lively and sometimes heated debate it did addresses the significant change in Networks as we know that 5G will bring.  

Among other things, 5G will provide dramatically faster speeds, and thus, greater overall bandwidth, which sounds great for wireless devices. But mobile networks don’t exist by themselves. The new 5G network and the devices that use it will need a network that supports them on the back end so that the data they need and the computing services they require can be available with as little latency as possible. That low-latency requirement will be more insistent than ever as services like self-driving transports will need to transfer data almost instantly in order to do their jobs.

Latency can be thought of as a network delay, but it’s really caused by several factors, the most basic of which is the speed of light in glass fiber. The longer the distance a data packet has to travel on a network, the longer it’ll take to get to its destination. While it’s still measured in tiny fractions of a second, those fractions add up as other factors join in. So does the time it takes a server and whatever application or database in running to find the information you need and send it back to you. As the network gets busier, and the network infrastructure becomes less able to cope with the traffic, latency increases. This is especially true with servers as they become overloaded.

Because communicating with a centralized computing and data repository takes time, the only way to save time (i.e. decrease latency) is to avoid using that centralized repository—which means moving big chunks of your network’s computing power to the edge of the network. The result is something called “edge computing,” with architectures referred to as “edge cloud computing,” which, in turn, uses things called “cloudlets” or sometimes called “fog computing.” A key driver is mobile computing, which necessarily uses data at the edge.

The edge of the network is the part that’s closer to the ultimate user. By moving the data to the edge of the network, you cut down on delays in two ways: First is that you reduce the distance between the user of the data and the place where it’s stored (the repository), which reduces the time it takes data to move back and forth. Second, by keeping just the required data near the user, you’re also reducing the amount of data that the server has to handle, which also speeds things up.

While it's common to assume that cloud and edge computing are competing approaches, it’s a fundamental misunderstanding of the concepts. Edge computing speaks to a computing topology that places content, computing and processing closer to the user/things or “edge” of the networking. Cloud is a system where technology services are delivered using internet technologies, but it does not dictate centralized or decentralized service delivery. When implemented together, cloud is used to create the service-oriented model and edge computing offers a delivery style that allows for executions of disconnected aspects of cloud service.

Computing at the edge with user devices included are already playing important roles. Edge analytics is a rapidly growing field to process and make use of local traffic in ms latencies. There is also a broad set of new requirements coming from 5G use cases such as tactile internet, real-time video traffic optimization etc. Various industry initiatives are creating environments where application programs such as analytics are easily pluggable into the open mobile edge cloud. Furthermore, additional resources obtained from edge networks that are time-critical and client-centric tasks should be placed in close proximity to the users.

5G systems are designed so that networks can be sliced on an as-a-service basis, with services scaled up and down quickly and easily and each slice can be customized to provide the elements necessary for the architecture it requires. For example, 10 percent of a network’s resources can be reserved exclusively for IoT devices, however this requires new 5G core built on service based architecture. 

With 5G, operators need to consider both devices: the sender, and the end device.  A good example is for M2M and IoT applications where the battery life of the device needs to be considered. An operator can customize the network for a low-power application so battery life can be measured in months or even years in some cases. The 5G era will bring to life amazing use cases, mostly encompassing mobile broadband, massive IoT, and mission-critical IoT. Network slicing offers better business agility, flexibility, and cost-efficiency. The network slicing as-a-service model lets network operators choose the characteristics they need per slice to reach 5G capabilities, such as less latency with more throughput, connection density, spectrum efficiency, traffic capacity, and network efficiency.  This helps increase business model efficiencies in how they create products and services as well as improve the customer experience.   

Additionally, each slice is isolated and comprises the device, access, transport, and core network, thereby increasing reliability and security. Also, changes and additions to a slice can be made without having to consider the effects across the rest of the network. This saves time, effort, and cost because it takes away the need to re-engineer the whole network with individual slice changes. 

Networks are moving away from a one-size-fits-all model and toward a model where unnecessary functionality is removed and new technologies can be added where needed. Network slicing combines a common underlying infrastructure where resources can be divided, shared, and optimized. This is a more cost-effective use of the resources and helps reduce the total cost of ownership.

Ultimately, network slicing will allow IT to achieve more at a lower cost. Individual timelines, services, and pricing can be created and still retain the benefit from the common infrastructure. At the end of the day, network slicing will likely be invisible to the typical end user, but will allow network operators to be more nimble, more flexible, and ultimately cost-effective, which should enable a better user experience for everyone.

This in my view is the main reason why in the initial stages of 5G the core network and core network capabilities will be more important than the edge, but over time as 5G matures and we start seeing more and more new innovative and localised services, the importance will over time shift towards the edge.

[Keywords] Core, Edge, 5G, computing at the edge


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