5G NSA & SA Networking
Odul Kivrak – o00441218
5G Use Case Design Team
December, 2022
Huawei Technologies Co., Ltd.
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Content
Differences Between NSA and SA
Non-Standalone Architectures for MNOs
Standalone Architectures (SA) for MNOs
NSA and SA, and The Future of 5G
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Differences Between NSA and SA
The main difference of NSA (Non-Standalone Architecture) and SA (Standalone Architecture) is that NSA anchors
the control signaling of 5G Radio Networks to the 4G Core, while the SA scheme connects the 5G Radio directly
to the 5G core network, and the control signaling does not depend on the 4G network at all. NSA, as the name
suggests, is a 5G service that does not ‘stand alone’ but is built over an existing 4G network. SA, on the other hand,
allows completely independent operation of a 5G service without any interaction with an existing 4G core.
Per 3GPP TR 21.915, Two deployment options are defined for 5G:
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The “Non-Stand Alone” (NSA) architecture, where the 5G Radio Access Network (AN) and its New Radio (NR)
interface is used in conjunction with the existing LTE and EPC infrastructure Core Network (respectively 4G Radio
and 4G Core), thus making the NR technology available without network replacement. In this configuration, only
the 4G services are supported, but enjoying the capacities offered by the 5G New Radio (lower latency, etc). The
NSA is also known as “E-UTRA-NR Dual Connectivity (EN-DC)” or “Architecture Option 3”.
The “Stand-Alone” (SA) architecture, where the NR is connected to the 5G CN. Only in this configuration, the full
set of 5G Phase 1 services are supported.
Image from GSMA
Non-Standalone Architectures for MNOs
The path that mobile network operators (MNOs) follow to 5G will depend a lot on how they plan to pay for that
journey. During the deployment of 4G from 2010-2015, virtualization was not a mandate. Operators took many
different approaches to deploying 4G architectures utilizing proprietary and virtualized solutions. With 5G,
virtualization is a must. MNOs now have an opportunity to transform the way they build and operate their
networks.
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For MNOs that are looking to deliver mainly high-speed connectivity to consumers with 5G-enabled devices, a nonstandalone architecture (NSA) makes the most sense, because it enables them to leverage their existing network
investments in transport and mobile core —rather than deploy a completely new end to end 5G network. This can
be combined with efforts to reduce network operating costs by adopting virtualization and CUPS (Control and User
plane separation) using software-defined networking (SDN). These initial steps toward 5G, enable MNOs to begin
offering 5G services providing faster data speeds and capture additional revenue streams.
Benefits of 5G NSA:
deliver high-speed connectivity to consumers with 5G-enabled devices
leverage existing network investments in transport and mobile core
Standalone Architectures (SA) for MNOs
For some MNOs, however, who have their sights set on new enterprise 5G services such as smart cities, smart
factories, or other vertical market solutions, a standalone architecture (SA) could make more sense. In this
scenario, which 3GPP has now standardized, MNOs can build an entirely new fully virtualized 5G network that
includes new radio access network, new transport network, and new 5G mobile core and edge networks – standing
alone and separate from their existing 4G and legacy networks. 5G standalone architecture is a fully virtualized,
cloud-native architecture (CNA) that introduces new ways to develop, deploy, and manage services. CNA includes
concepts of microservices and service-based interfaces that greatly simplify services, dramatically reducing the cost
of operation and speeding up the introduction of new revenue-generating services. With 5G SA, the distinct
advantage here is end-to-end support for 5G speeds and services. And the true promise of 5G is enterprise-driven
revenue – it changes the business model from consumer-driven to enterprise-focused opening up entirely new use
cases and revenue streams.
Benefits of 5G SA:
MNOs can launch new enterprise 5G services such as smart cities, and smart factories
It is fully virtualized, cloud-native architecture (CNA), which introduces new ways to develop, deploy and manage
services
The architecture enables end to end slicing to logically separate services
Automation drives up efficiencies while driving down the cost of operating the networks.
By standardizing on a cloud-native approach, MNOs can also rely on best of breed innovation from both vendors
and the open-source communities
By choosing a cloud-native microservices-based architecture, MNOs can also decide on a variety of deployment
models such as on-prem private cloud, public cloud, or hybrid to meet their business objectives
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The Future of 5G Includes NSA and SA
It’s worth noting that NSA and SA aren’t an either/or proposition, but more of a “sooner or later” consideration.
MNOs that begin with NSA can gradually add or migrate to SA over time. What we’ve seen at Affirmed from early
5G adopters are primarily NSA deployments as MNOs compete for the bragging rights (and the competitive
advantage) of being the first to offer 5G speeds. These MNOs were typically the first to adopt 4G/LTE technologies
as well, and so are fairly advanced in terms of network virtualization. Many of them are still using Affirmed’s
solution as their virtual Evolved Packet Core (vEPC) solution. One of the advantages of Affirmed’s NSA-based
solution is its ability to handle both 4G and 5G-based traffic as MNOs transform their networks.
At some point, of course, NSA and SA will converge as MNOs move to a full 5G architecture. Recognizing that,
MNOs would do well to look for a mobile core platform that can transition easily from non-standalone to
standalone. Having a completely virtualized 5G architecture will offer MNOs the flexibility to migrate select
functionality of their existing NSA solution to the 5G core platform over time, as new 5G services are enabled,
allowing them to monetize their investment gradually rather than go all-in and hope to recoup their costs later.
With a clear path to evolving their networks from NSA to SA, Mobile Network Operators can win the race to
revenues by operating their networks at webscale. Learn more about our 5G core solution.
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