Apis TechTip – What is Network Slicing?

Welcome to this episode of Apis TechTips, a series of short explainer excerpts from real Apis training courses.

This episode gives a concise logical description of network slicing, and it comes from the course “Network Slicing in an Hour”.

If you enjoyed this Apis Tech Tip, check out the full Apis course ” Network Slicing in an Hour” where this video came from. There you will get a condensed view of the 5G Network slicing feature as defined by the 3GPP. It presents operational benefits and explains the technology needed to realize network slicing in 5G.

Here are some of the topics that are covered in “Network Slicing in an Hour”:

  • Network Slicing: Overall Perspective
  • Technological Aspects of Network Slicing
  • Business Aspects of Network Slicing

To learn more about this course, go to https://apistraining.com/portfolio/network-slicing-in-an-hour/

This TechTip is also part of a whole eBook of tips, all focusing on 5G technology. We call it an eBook+ since all chapters are both text and video. If you want to read the text, you can do that, and if you want to watch a teacher tell the story, you can choose that.

All the video chapters are excerpts taken directly from our recorded lessons, so if one of them piques your interest, you can easily go to the course and dive deeper into that particular subject.

This particular eBook+ is called “5G Demystified: Use Cases, Architecture, and More”, and you only need to CLICK HERE to request it for immediate download.

Below you can find the transcribed text for this particular TechTip.

What Is Network Slicing?

I would like to start us off with an overall picture, just putting together some of the most important information about network slicing. A network slice is a logical network that is kind of placed on top. It’s an overlay on an actual physical infrastructure. And the purpose of having this logical network is to have use case-specific settings, which means it’s no longer one-size-fits-all.

Now, looking at the image, the boxes in the green, red, and blue shapes are supposed to represent the physical infrastructure that we are going to be using. And just to be clear, such a box can mean a physical piece of equipment. ”Compute” means processing power, ”storage” means databases, and ”networking” means the cabling that interconnects them. So, these three would be physical things.

But such a box can just as well be a specialized piece of software. It can be something virtual. Virtual machines is a term that comes to mind, but other solutions for virtualization exist. We can talk about containers, and we can talk about microservices. These are techniques for virtualization, and they can be applied in the 5G Network Functions or the 5G network services.

So, these boxes are not necessarily physical things, but they are our resources. And what we are going to do now is we are going to overlay things onto that actual infrastructure. We are going to overlay our, in my example, three different logical networks (coloured shapes). Each and every one of these three different logical networks has well-defined capabilities and is going to handle certain groups of services.

The divisions between logical networks and the network definitions are going to be a result of the operator discussing with its customers what it is they actually need. The key things about the different logical networks are two buzzwords. The network resources for a network slice are dedicated, and the network resources between different slices are independent of one another.

This is the biggest benefit of having network slicing. So, let’s make sure we understand these words. Dedicated resources. What does the term ”dedicated” mean? First of all, it can mean dedicated to certain services, which means that we prepare our capabilities in this logical network to fit the needs of a certain type of application. And then we can call this package a communication service.

For a particular communication service, we will define its characteristics. These can be the quality of service, mobility, power-saving mode, battery saving, these kinds of things. The list of characteristics can be really, really long. So, you can have resources that are dedicated to a particular service or application.

The other way of having dedicated resources carries yet another benefit of network slicing with it. You can have resources dedicated to different customers, and this means that a network slice becomes a business proposal. It becomes something tangible that an operator can sell to another company and put a price tag on.

So, who are these customers? The term ”vertical” started being quite big in the 5G environment. Verticals are simply different business players of a certain type. From time to time, we talk about private networks. A network slice can be offered as a service, and then it can be, for example, a private network. And generally, a Network Slice as a service is a business offer.

You might know the abbreviation MVNO, Mobile Virtual Network Operator. They’ve been around for years, and it’s basically a different brand name, a different business, but the owner of that business sits on top of an actual operator’s infrastructure. And mobile virtual network operators are among the customers that can use a network slice.

I am talking about a world in which a mobile operator has an operation and maintenance system, and somewhere in the war room, a person pushes one button, and a completely new virtual network pops up. And that’s all the work that needs to be done. Of course, I’m a bit simplistic here. There is a lot of work around it, but that’s at least the direction that we are heading.

So, the resources can be dedicated either to a service or to a customer. What about the other term, ”independent”? This actually boils down to another keyword in the network: isolation in 5G slicing. Independent means that things that happen in the green network slice don’t affect whatever is happening in the blue one and vice versa. That’s isolation.

Maybe you’ve noticed I’m being a little vague on purpose. What does it mean that things that are happening don’t affect other things? It’s not the very technical term, the word isolation. A lot of people interpret it to mean isolation of resources. But please notice that isolation can refer to a whole number of aspects.

You can have isolation of functions, configurations, policies for resource usage, failure domains, and security domains. This is a big, big term. What I’m saying is that we can have isolation between slices, and this is a big benefit. This is what the operators are after.

Now, speaking of benefits, at the bottom of the illustration, I’ve tried to compile a list that summarizes what is seen as the most important things we gain with network slicing. The first statement, I would guess, is quite straightforward. It simply says that network slicing allows us to support the services and verticals that we have identified. They need this, and we are addressing a need on the market that we are aware of.

On top of that, we also have new use cases. With the tool that network slicing is, we can actually come up with new and interesting offers. This can be both for individual customers and for enterprises like the Network Slice as-a-service, for example, towards MVNOs. The technology itself, from an operator’s perspective, must be reasonably cheap, though. It’s the whole profitability question.

Next comes scalability. Resources can be allocated according to need, and this can be done dynamically. Where does this come from? Well, from the fact that the logical networks that I’m talking about are using the underlying enabler of virtualization. So this is actually a benefit that comes together with the technology that we are using.

We also get fewer dependencies and consequences to consider at the start of a dedicated network for a new service. This is a very important statement because if we are starting to talk about a world in which one operator of this physical infrastructure has to carry a number of logical overlay networks, this is a level of complexity that can be absolutely startling. So this bullet point essentially says, don’t worry if you add yet another network slice onto your network. You might, of course, have problems with this particular network slice. But the other already up-and-running slices will not be affected, which is an important statement in its own right.

This independence also has another effect, and that’s the last bullet point. If I can add a new logical slice onto a live network without affecting the other elements, well, this makes it a fantastic sandbox for testing new ideas. So, the network slicing feature makes it easier to develop our service offer.

Until now, I was talking about the network slicing concept on a generic level, but the actual term network slicing comes from the standards of the Third Generation Partnership Project (3GPP). So, to stick to the naming convention, we have to know where the naming comes from, and the network feature and the 3GPP standards of overlaying logical networks did not start in 5G.

I just want you to be aware of the term dedicated core networks, sometimes referred to as DECOR. Dedicated core networks is an equivalent feature that was introduced for a 4G environment. So, it was for the LTE or for the evolved packet core (EPC), and these definitions can also be applied to 2G and 3G.

Having said that, dedicated core networks is a feature that exists, but pretty much just on paper or in the form of bits in files. To put it mildly, it’s not heavily used, but the corresponding solution in 5G is actually viewed as the absolute cornerstone of the extra features that we are going to get with 5G.

So, it’s a feature that is almost unused in 2G/3G/4G but expected to be a basic feature of 5G. Interesting. We’ve simply evolved to the point in time when deploying this makes a lot of sense to us. On the left of the illustration is a small picture, which is supposed to show us an overview from an architectural perspective of what a network slice is.

So you can see on the left the RAN or the radio access network. I’m not trying to say that the RAN is a cloud environment. I just use a cloud shape to say that this is one physical radio access network with its corresponding transmission and reception. And at the end, the radio interface towards an end-user device, the user equipment (UE). It’s wireless access; it’s a radio access network.

On the right side of this small part of the illustration is my 5G core. A network slice is the access network part plus the core network part. So, it spans all the way across the access and core network down to the user equipment.

If you look at this basic definition, have you noticed that these two network slices are represented with different colors (pink and green)? But they both go to the same device. This is just to underline the fact that one user equipment can use multiple network slices. What’s more, we expect that this is what will be happening.

So, if this is an image that summarizes everything, let’s not forget that network slicing sits on top of the underlying technology, which is virtualization. So, virtualization is a must if we want to have network slicing.

And if we have more and more and more of these logical networks placed on top of a physical infrastructure, this does introduce other issues as well. Like the scalability of what I like to call satellite systems around the actual transportation network, the most important of which I think is operation and maintenance. So, let’s not forget that operation and maintenance of a huge number of logical networks running on our physical network is a challenge in and of itself.

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