Journey to a Converged Core, A Technical View

5 years have handed because the early drop of 3GPP’s Launch 15, launching the industrywide journey in pursuit of 5G.  And as we speak 5G continues to be evolving, as subsequent releases and pending future releases proceed to outline the capabilities and providers enabled by the 5G structure.  In hindsight, most advertising groups would admit they jumped the gun on 5G, setting overly excessive expectations with the promise of latest experiences.  And whereas the largest promise of 5G has at all times been velocity, the community transformation to get there was something however quick.  Migrating from monolithic legacy architectures to a 5G service-based structure (SBA) has proved to be a frightening job, nevertheless this transformation stays essential for the profitable monetization of the brand new experiences and capabilities that 5G has been promising to ship.

A quick historical past of 5G and innovation

On the heart of 5G innovation is the core.  The 5G Core is a rethinking of how now we have carried out issues previously, but maintains a backwards compatibility with the 4G LTE period whereas including profound advantages for 5G:

• The 5G Core fixes among the limitations of 4G – for instance, Session and Service Continuity (SSC) modes, Entry, and Session Administration separation
• Management and Consumer Aircraft separation is designed as a part of the structure from day one, enabling edge computing use instances (MEC), excessive bandwidth, and LBO to call a number of, all of which may be delivered simply and economically
• Protocols like SBI (Service Based mostly Interfaces) allow new improvement architectures for the 5G Core resulting in extra speedy innovation
• The 5G Core profiles and guidelines may be deployed granularly via strategies corresponding to community slicing, and community coverage

We may go on for pages and pages, bulleting out options and advantages of 5G, typing a listing which will by no means finish as future characteristic releases proceed to refine and add enhancements. And whereas all these new capabilities that 5G is bringing sound nice, there’s a distinction between what has been put to paper and what’s being carried out in the true world as we speak.  For instance, many new 5G use instances require gadgets to help N1 NAS protocols.  With new 5G gadgets and a model new 5G SA packet core that is no downside.  However we reside in the true world full of current 4G providers and others earlier generations of gadgets that don’t help the brand new protocol(s). Most of those gadgets work nice as we speak and don’t have any instant should be changed.  Thus, supporting a number of generations of expertise has led to a necessity for sustaining two cell cores, one that can help 4G legacy NAS protocols and 5G NSA gadgets with legacy NAS protocols, and a second core for supporting the newer 5G N1 NAS gadgets.

Two Cores, no downside?

On the floor, including one other core only for 5G wants doesn’t seem like too difficult and it isn’t.  In an ordinary occasion, packet cores (e.g., SMF, UPF, PGW, SGW, PCRF, PCF, and many others.,) may very well be deployed and managed in parallel.  Working two cores in parallel is just not optimum and such a configuration presents vital challenges for outlining coverage and subscriber knowledge administration.  Any communication service supplier contemplating this route might want to make use of a number of operations groups and a few inventive engineering for sustaining their supply packages.  With two cores you might be successfully doubling the prices and dangers with out coming near doubling the reward.  Thankfully, there’s an intriguing various to working two cell cores in parallel and that’s discovering a mechanism for converging the core features right into a unified structure.

We set out on this path years in the past, working intently with service suppliers, like T-Cellular, to know the challenges they confronted and the worth of a converged core.  Whereas there has at all times been loads of noise about 5G NSA and 5G SA deployments, with T-Cellular we centered past that to outline an structure for a “Converged Core”.  This meant bettering operations, buyer expertise, and total subscriber high quality whereas sustaining what already existed.   We name it a “Converged Core” as a result of it brings collectively the previous, current, and way forward for cell core applied sciences.  There are different names for this within the trade corresponding to a “Unified Core” or an “Any Era Core” that describe the identical concept.  We leveraged our experience because the trade chief in 4G packet cores, matching market necessities with technological capabilities to construct a smoother path ahead to 5G with a converged core.

Addressing the Enterprise Outcomes

The Cisco Converged Core addresses the essential enterprise challenges skilled by our service supplier companions, together with:

• The power to outline coverage at one location and apply the coverage throughout entry networks (4G, 5G, Wi-Fi)
• The power to cut back operations prices with a single, unified platform as an alternative of working a standalone 4G core and a standalone 5G core, in parallel
• The power to rapidly deploy new client and enterprises providers in a unified method, whatever the finish customers entry necessities
• A unified billing and help expertise for the top prospects

What’s the Converged Core?

The Converged Core is the guts of the cell community.   In distinction to earlier generations of expertise, 5G Cores are software program based mostly and outlined by 3GPP’s Service Based mostly Structure (SBA)–a set of interconnected community features (NFs).   These community features, such because the Session Administration Operate (SMF), Entry Administration Operate (AMF) and the Consumer Aircraft Operate (UPF), to call a number of, are containerized software program that helps the separation of the management airplane from the person airplane.  As an alternative of {hardware} dependencies and the point-to-point (P2P) limitations of the earlier technology’s expertise, the Service Based mostly Structure (SBA) is supposed to be a flat, constructed for portability and scalability with the cloud. Every perform is cloud-native and far completely different than their predecessors. Take the SMF, for instance, the SMF gives widespread session administration for all accesses, together with WLAN, and handles all session administration signaling for person tools (UE) which is relayed by the Entry Administration Operate (AMF).  In 4G architectures, a few of these capabilities are supplied by the Packet Information Community Gateway Management Aircraft Operate (PGW-C). The remaining management airplane components together with the Serving Gateway Management Aircraft Operate (SGW-C) and Packet Information Community Gateway Management Aircraft Operate (PGW-C) together with the session administration features from the previous Mobility Administration Entity (MME) have been additionally migrated into the brand new Session Administration Operate (SMF).

Relative to the Session Administration Operate (SMF), the Consumer Aircraft Operate (UPF) helps a set of operations corresponding to forwarding to different features, encapsulation/decapsulation of information, bitrate enforcement, and software detection. The Session Administration Operate (SMF) can dynamically activate and configure the Consumer Aircraft Operate (UPF), or a subset of Consumer Aircraft Features, to supply the visitors dealing with performance wanted for a session.  Inside the 5G structure, one or a number of Consumer Aircraft Features (UPF) may be activated and configured by the Session Administration Operate (SMF) per session, or as wanted per software. At a excessive degree and in contrast to 4G, which has distinct person airplane entities (SGW-U or PGW-U), the 5G SBA consolidates these entities with the Consumer Aircraft Operate (UPF).  Successfully establishing a common model of the 4G core’s person airplane components, inclusive of the Serving Gateway Consumer Aircraft Operate (SGW-U), Packet Information Community Gateway Consumer Aircraft Operate (PGW-U) and the Visitors Detection Operate (TDF).

The decoupling and reshuffling of community features’ roles and tasks between a 4G core structure and the 5G Service Based mostly Structure (SBA) has been each a problem and alternative.  Rewriting and implementing community features to be backwards suitable and forwardly compliant was gradual and tough, however price it. Just like the fable we study at a younger age, gradual and regular wins the race, particularly when belief and reliability are of utmost significance.  Our strategy to the enterprise issues and technical challenges of supporting a number of entry applied sciences (4G, 5G, and Wi-Fi) was to construct a composable 5G converged core that communication service suppliers like T-Cellular can use to deploy capabilities as wanted.  Elementary to the design of Cisco’s Converged Core is being cloud native, a containerized answer supporting each 5G gadgets and legacy 4G gadgets, on the identical platform, thereby eliminating the necessity for a separate 4G Packet Information Community Gateway (PGW), two units of insurance policies deployed in two completely different places, and a future stuffed with complications.

The Cisco Converged Core is aligned with 3GPP’s TS 23.501 and TS 23.502 definitions for non-roaming structure interworking between 5G and EPC/E-UTRAN. To simplify the deployment, SMF+PGW-C as outlined by 3GPP is interpreted as SMF+S5-C, with out a full PGW-C however with the flexibility to help the S5 Management interface on the SMF. Equally, UPF+PGW-U, as outlined by 3GPP, can also be interpreted as UPF+S5-U.  This strategy, , permits communications service suppliers emigrate e and leverage a Service Based mostly Structure through the use of the brand new South Sure Interfaces (SBI) outlined in 3GPP.  The result’s centered investments and a clean migration path for a communication service supplier’s 5G journey.

With a Converged Core communication service suppliers can help 4G gadgets connecting through the Mobility Administration Entity (MME) and the Serving Gateway (SGW) in 4G or 5G NSA architectures to be anchored on the identical Session Administration Operate (SMF) and Consumer Aircraft Operate (UPF) as a tool that will join through the Entry Administration Operate (AMF) in a 5G SA structure.  All capabilities northbound corresponding to Coverage through Coverage Charging Operate (PCF) and Charging through Charging Operate (CHF) are supported utilizing new service-based architectures which communication service suppliers can use to unify choices and focus essential investments.  The structure additionally permits for ease of mobility throughout protection domains i.e., 4G LTE, 5G NSA and 5G SA creating a way more seamless expertise for finish customers.

Main with this structure, the Cisco workforce developed a single converged core platform that may be deployed and configured, as wanted.  Taking the deployment structure one step additional, the Cisco Converged Core may be deployed in numerous variations relying on operator use instances:

1. Standalone 5G SA Session Administration Operate (SMF) and 5G Consumer Aircraft Operate (UPF) solely
   1. Usually used for 5G SA solely use instances corresponding to Fastened Wi-fi Entry (FWA) with 5G SA gadgets
   2. System Sorts supported: 5G SA Succesful

2. SMF+S5C and UPF+S5-U mode to allow exterior Serving Gateway (SGW) integration
   1. Usually used for migrating in a multivendor setting the place current investments within the Serving Gateway (SGW) are leveraged for prolonged interval or when utilizing particular roaming architectures
   2. System Sorts supported: 4G, 5G NSA, 5G SA

3. Session Administration Operate (SMF) + Serving Gateway Management Aircraft Operate (SGW-C) and the Consumer Aircraft Operate (UPF) + Serving Gateway Consumer Aircraft Operate (SGW-U) as an entire converged core
   1. An optimized footprint deployment for supporting a single unified operations
   2. System Sorts supported: 4G, 5G NSA, 5G SA

Abstract

By main with a unified product structure that permits in-field selections on how one can configure and deploy numerous use case particular fashions, the Cisco Converged Core:

• Reduces studying curve for communication service supplier operations groups
• Simplifies administration and operations by unifying coverage and repair choices
• Improves end-user experiences
• Offers service parity for communication service suppliers migrating from current Cisco 4G deployments
• Economizes investments within the structure of the long run

Cisco has lengthy been an trade chief in cell cores and our Converged Core answer continues that management by delivering outcomes tightly aligned with our communication service supplier buyer wants.   Migrating from 4G providers to the 5G future is a journey finest made with companions you may belief.  The Converged Core is repeatedly bettering, including new capabilities, and optimizing itself because it evolves.  With new use instances for communication service suppliers and enterprises alike on the horizon, the alternatives for innovation appear limitless.

Assets

Go to our product pages to study extra about how the Cisco Cloud Core and Packet Core portfolio

To study extra about T-Cellular and Cisco Launch of the World’s Largest Cloud Native Converged Core Gateway, learn the December 2022 press launch

Share: