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White Paper

Cisco 5G Vision Series: Laying the Foundation for New Technologies, Use Cases, and Business Models

What You Will Learn

The fifth generation (5G) of mobile networking standards is in the early stages of development. Cisco is actively

engaged in defining its requirements and leading engagements to address how 4G LTE networks will gracefully

evolve to 5G by 2020. This white paper describes the primary drivers for the creation of 5G, the technologies

proposed by the industry for inclusion in 5G standards, and the expected timeline for 5G completion and rollout.

Also included are an overview of Cisco’s vision for 5G technologies and examples of Cisco engagements meant to

evolve current 2G/3G/4G mobile networks based on the new 5G technologies across the RAN, the mobile core,

and the next-generation Internet. Other papers in this series go into greater detail about RAN evolution, mobile

core evolution, and the next-generation Internet evolution in the context of 5G standards.

Introduction

Since the advent of electrical engineering in the nineteenth century, no single mobile electronic device has

surpassed the cell phone in popularity. According to the International Telecommunications Union (ITU), 6.8 billion

people had access to cell phones in 2013: more than had access to toilets, according to research by the United

Nations. And by 2015, a third of the 7.2 billion people on Earth were using a fourth-generation long-term evolution

(4G LTE) network.

Now, the growth of the Internet of Things has hastened the definition of a vision for 5G standards that the ITU

ratified in September 2015 as the International Mobile Telecommunications system for 2020 (IMT-2020). The 5G

standards will be “focused on enabling a transparently connected society… that brings together people along with

things, data, applications, transport systems and cities in a smart networked communications environment.” Work

has begun on 5G among many different organizations and companies. Additionally, there is significant work in

progress on how the evolution of 4G LTE networks between 2015 to 2020 will include the transparent integration of

5G systems.

As shown in Figure 1, every new mobile generation has been based on significant new capabilities and features.

2G added digital mobile communications. 3G provided step function improvements in voice capacity and quality

along with high-speed data. 4G introduced broadband data and IP-based voice through an all packet core network.

http://www.cisco.com/web/solutions/trends/iot/overview.html


Figure 1. The Evolution of Mobile Standards

5G standards are being developed in response to:

● The need for greater capacity and scalability

● Use cases requiring improved performance (for example, very low latency)

● Evolving new business models that support vertical markets requiring new network capabilities

Figure 2 shows the main areas of technological advances expected with 5G to address these drivers. Many of

these 5G technology advances will have an effect across the entire mobile topology from the RAN to the core

network and will additionally influence the evolution of the Internet to address current limitations based on modern

usage patterns.

Figure 2. Primary Technology Areas in 5G


While 5G requirements are being developed by organizations such as the ITU, the industry is not waiting on the

IMT-2020 initiative. Early prototyping and development of primary technologies across the various 5G technology

areas in Figure 2 have already begun. Cisco is actively engaged in development of technologies and architectures

to support RAN evolution, core evolution, and Internet evolution of 2G/3G/4G networks that will lay the foundation

for 5G.

Drivers for 5G Usage Trends Require Cost-Effective Solutions

The Cisco Visual Networking Index (VNI) Global Mobile Data Forecast 2014–2019 projects exponential growth in

mobile data usage. By 2019, global mobile IP traffic will reach an annual run rate of 292 exabytes, as compared to

30 exabytes in 2014. That’s a significant compound annual growth rate of 57 percent.

Much of this growth will be driven by venues (such as stadiums, hotels, shopping malls, and other places where

masses of people congregate) and services offered within those venues. This type of use case requires an

increased need to densify the mobile network through deployment of Wi-Fi and small cells. While Wi-Fi has

demonstrated great success for populous venues, the licensed radio industry in general has been slow to adopt

and deploy small cells. The reason is a high total cost of ownership (TCO) because of factors such as site

acquisition, installation, and backhaul costs. These monetary challenges are in part caused by the deployment of

small cells currently by individual mobile network operators. This forces venue owners to deploy multiple small cells

(one per major MNO) to provide service to all of their customers. One of the goals for the evolution to 5G is to be

able to deploy small cells with multitenant capabilities in venues. In this case, the cost of site acquisition,

installation, backhaul, and other requirements would be shared across multiple MNOs and potentially even be

supported by the venue owner.

5G technology will operate in an environment with continued expected exponential growth in data traffic.

Additionally, the Internet of Things will result in the current array of user mobile devices being dwarfed by more

than 50 billion devices that are anticipated by Cisco to be connected to the Internet by 2020. These will include

everything from sensors in cars and kitchen appliances to telemetry devices, remote video cameras, and

attendant-free parking lots. Add to this proliferation of data and IoT the growth in smartphones: the Cisco VNI

estimates smartphones will grow from 29 percent of mobile devices globally in 2014 to 40 percent by 2019. And

then there is the growth of total mobile devices around the world: the Cisco VNI forecasts that the total number of

devices and connections will grow from 7.4 billion in 2014 to 11.5 billion by 2019.

This spiraling growth trend in the number of connected devices will require a high degree of scalability.

Unfortunately, this massive increase in connectivity is not expected to be matched by a massive increase in mobile

operator revenue. The Groupe Speciale Mobile Association (GSMA) predicts that the emergence of low-power

wide area networks (LPWANs) focused on supporting the Internet of Things will lead to a rapid decrease in per

connection revenue. 5G mobile technology will have to support a significant drop in average revenue per user

(ARPU).

Another usage trend of note is the type of applications that are driving mobile data usage growth. As shown in

Figure 3, video is expected to be 72 percent of mobile data traffic by 2019. This is another particularly challenging

trend given that video requires orders of magnitude more bits to be transmitted than voice, which adds to MNO

costs as ARPU is declining. Another challenge for MNOs is the transition to end-to-end encryption (E2EE) on the

Internet using, for example, Chrome browsers currently using SPDY and in the future HTTP/2. E2EE makes it

difficult for MNOs to identify video traffic and optimize it to provide the highest quality of experience to the end user

(which could improve their willingness to pay for better service).


This trend is leading some MNOs to acquire or sign agreements with content owners to be able to better manage

the content, understand what content is being watched by specific users, and potentially provide targeted

advertising. 5G standards must address these trends and business models.

Figure 3. Application Usage Trends

Diverse Use Cases Require Better Network Performance

In addition to mobile data usage trends driving up capacity and the need for scalability in 5G, use cases that

provide new business opportunities require better network performance. That means lower latency, wider coverage

in the right places, higher mobility, and higher reliability. And all of those features need to be affordable.

A comprehensive study of potential 5G use cases by the Next Generation Mobile Network (NGMN) Alliance

identified eight families of use cases, as shown in Figure 4.

Figure 4. 5G Use Case Families and Related Examples


So it is clear that 5G must have the flexibility to support a very wide range of requirements encompassed by the

variety of use cases shown. For example, broadband access in dense areas compared to massive IoT use cases

represent two ends of the spectrum (for example, from very high bit rates in dense areas requirements for

applications such as pervasive video to very low bit rate very wide area coverage requirements for apps such as

IoT sensors). Add to this the use cases focused on extreme real-time communications and ultrareliable

communications, and many more requirements for 5G arise.

So the ability to flexibly and efficiently support specific use cases for specific devices using specific network and

RAN functions is a primary area of definition for 5G standards. 5G networks must provide flexibility to

simultaneously instantiate multiple logical network partitions to support a wide range of use cases. This last

technique is called network slicing. It’s an important capability that must be realized in the 4G evolution to 5G. A

separate paper in this series goes into much greater detail.

New Evolving Business Models Support Indoor Use and Value Chains

A “2015 State of the RAN” white paper by Amdocs cited its research finding that 80 percent of mobile data is being

consumed indoors, usually through a Wi-Fi connection. Meanwhile, another growing trend is green building

initiatives that focus on improving the energy efficiency of offices and homes. These initiatives have led to the wide-

scale adoption of radiation barriers in new building construction, including metalized coatings on windows and foil-

faced sheathing in walls and roofs, both of which improve the thermal properties of the building but restrict RF

penetration. Hence, 5G will be deployed in environments where the majority of data is being consumed indoors

and the indoor users are increasingly harder to serve from an outdoor installed base station. So 5G mobile

technology and its operational features will have to make integration of indoor systems to optimally support the

massive adoption of mobile data by indoor users easy and reliable.

While indoor systems can be used to support existing mobile broadband services, 5G will also need to address

business models that include value chains outside of traditional MNO-centric coverage and capacity. So the 5G

system must be defined to service these new opportunities. It must create value chains on a converged

infrastructure using standardized APIs that expose information associated with a set of value creation

opportunities. A NGMN white paper describes nine areas of value creation that complement baseline network

connectivity, as shown in Table 1.

Table 1. Value Creation Opportunities in 5G Networks

Category Description

Security Provide state-of-the-art security for all communication, connectivity, and (cloud) storage purposes

Context Utilize contextual information assets to improve network operation and to enrich service offerings to end customers and partners

Privacy Safeguard sensitive data while making sure of their full handling transparency

Real-time experience Enable perceived real-time connectivity to allow for instantaneous remote interaction

Transparent experience Hide the complexity involved in delivering services in a highly heterogeneous environment (for example, multiple access technologies, multiple devices, roaming)

Personalized experience

Dynamically customize a delivered service experience based on customer context and a differentiated customer-configurable product portfolio

Responsive interaction Identify events in real time and apply the required business process in real time (for example, real-time charging)

Quality of experience Guarantee agreed quality of service, reliability, and connectivity levels toward end customers and partners over time and across the service coverage

Identity Provide a trusted partner for one (master) identity, providing for secured, hassle-free, single sign-on and user profile management to fit all communication and interaction demands


Legacy mobile networks have been largely monolithic and inflexible in providing ubiquitous access for their

supported value chains. By contrast, 5G networks and resources need to be able to be logically partitioned into

different slices, providing the necessary functionality to support a particular use case and associated value chain

and avoiding all other unnecessary functionality. These logical slices will allow the different use cases to be

supported on a common, shared infrastructure. The associated network sharing support has been highlighted as a

foundational capability of 5G systems. This capability will make sure that new as-a-service consumption models

can be utilized by partners that support multiple connectivity providers with enriched services, as illustrated by the

NGMN Alliance in Figure 5.

Figure 5. New Business Models for 5G

Timeline for 5G and 4G Evolution

Whenever a new generation of wireless technology is being defined, developed, and deployed, there is often

confusion in the industry about exactly what differentiates one generation from the next. 4G LTE is just now

penetrating certain countries and is expected to evolve through LTE-Advanced (LTE-A) and beyond over the next

several years. And while 5G is being defined in the industry and standards bodies, several evolutionary trends are

happening to the 4G LTE evolved network that will set the stage for 5G. This includes the virtualization of the

evolved packet core (EPC) through network functions virtualization (NFV) and software-defined networking (SDN)

and the centralizing and virtualizing of the LTE RAN through the cloud RAN (C-RAN) and virtual RAN (vRAN).

What distinguishes 4G evolution from 5G? Or more broadly, what distinguishes one generation of mobile standards

from the next? At the early stages of development of a new technology, the IMT specifications from the ITU are

used to define the incoming generation of wireless technology. However, after the current generation deployments

have begun, there are subsets of those technologies that are used as foundations that are required to meet the

next generation of IMT specifications. These subsets are deployed and marketed with the understanding that they

will meet the IMT specifications for the next generation of wireless technology. For example, WiMAX 16e, LTE, and

even Universal Mobile Telecommunications Service (UMTS) and high-speed packet access (HSPA) deployments

were all marketed as 4G even though LTE-Advanced and WiMAX 16m were the only technologies meeting IMT-

Advanced requirements.


With 5G, we are still in the early stages of definition. Figure 6 shows the timeline for the 5G IMT-2020

requirements. The outcomes and decisions for which technologies meet these requirements will be made between

2019 and 2020. These requirements will clearly be the targets for 5G. However, as discussed earlier, some of

deployments featuring evolutionary technologies, solutions, and use cases will probably be marketed as 5G prior to

such deployments meeting all the IMT-2020 requirements.

Figure 6. Detailed Timeline and Process for ITU IMT-2020

Proposed Technologies for 5G

Even before the ITU published its IMT-2020 initiative requirements, companies had already been positioning their

favorite innovations for 5G. 4G Americas provided an exhaustive summary of 5G initiatives worldwide and potential

technologies for 5G in its “4 Americas Recommendations on 5G Requirements and Solutions,” October 2014.

Figure 7 summarizes many of these important technologies, which are already being developed as part of the

evolution of 4G LTE (the blue colored rows). The green colored rows represent new technologies envisioned for

2020. The blue colored rows represent particularly important technologies that will lay the foundation for 5G (and

possibly be marketed as 5G), even though they will be deployed as part of the 4G LTE evolution. The dark blue

rows are particularly important technologies that will be discussed in the next few sections about RAN and core

network evolution to 5G. The last green row, about information-centric networking (ICN), is an initiative led by

Cisco to define the next-generation Internet for 5G. It’s discussed in the final section of this paper.


Figure 7. Technologies Often Discussed in the Context of 5G

RAN Evolution to 5G

The table in Figure 7 lists several RAN-related technologies that are being discussed in the industry for 5G. With

each next generation of mobile technology, one of the first topics discussed is always the need for a new radio

access technology (RAT). Cisco believes in supporting better broadband mobile access in frequency bands <6

GHz and LTE-Adv. This continued evolution is likely to continue. However, for the mobile network to provide step

function increases in capacity and user quality of experience (QoE) that support fast growing data usage, it’s very

likely a new RAT will be defined and optimized that will use massive multiple-input and multiple-output (MIMO)

solutions in the millimeter wave (mmWave) band of 30–60 GHz.

The huge amount of spectrum available in the mmWave band will be critical for providing the very large throughput

and user QoE requirements expected in IMT-2020 for 5G. And, given the very difficult coverage challenges of

mmWave bands, massive MIMO provides a very attractive solution for enhancing mmWave coverage, particularly

because the size and required spacing of antenna elements at mmWave frequencies are very small, allowing for a

large number of antenna elements while maintaining small form factors in the solution.

Compared to previous generations of mobile technology, which have been designed to exclusively use licensed

spectrum, there is also an increasing acceptance that future mobile networks will need to operate using both

shared spectrum and license-exempt spectrum. For example, Table 2 compares the spectrum requirement

estimates from ITU-R M.2290 with current and future licensed spectrum availability in the United Kingdom as well

as available license-exempt spectrum availability. The table clearly demonstrates that by the time 5G emerges, all

operators will need to have adopted approaches for integrating licensed exempt spectrum into their service

offerings.


Table 2. Comparison of Spectrum Requirements and Typical Nationwide Availability

Band WRC 15 Future Spectrum Requirements (ITU M.2290)

Available Licensed Spectrum: 2015 to 2030 (UK)

Available License Exempt Spectrum

<400 MHz Low: 1340 MHz

High: 1960 MHZ

58 MHz

400 MHz – 6 GHz 2015: 380 MHz

2030: 654 MHz

1869 MHz

6 GHz – 50 GHz 13700 MHz

50 GHz to 250 GHz 22000 MHz

The need to accommodate higher frequencies together with adoption of license-exempt spectrum results in a

significant decrease in cell sizes. Small cells are naturally suited to tight spatial reuse of higher frequency bands

required to support the increases in traffic densities within the 5G environment. This explains the 5G focus of

supporting heterogeneous networks that compose dense deployments of small cells. Moreover, it is anticipated

that the characteristic peaks in traffic densities of today’s traffic and the trend for the majority of smartphone traffic

to be consumed indoors will continue.

Definitions for 5G mobile technology needs to recognize that since 4G has been defined, both IT and

telecommunications industries are being transformed by NFV, with the NGMN Alliance stating that “5G should aim

to virtualize as many functions as possible.” When it comes to RAN virtualization, however, it is commonly

accepted that not all functionality can be virtualized and that there will always be a requirement for a physical

element for implementing at least the 5G RF function. A precursor to RAN virtualization is the definition of a

standardized split between the physical network function (PNF) and the virtual network function (VNF). In 4G

mobile technology, the only standardized split has been the common public radio interface (CPRI) and open radio

equipment interface (ORI) between the radio equipment (remote radio head) and the radio equipment control (base

band unit). However, this interface was not originally designed to support RAN virtualization and includes

significant requirements for the fronthaul transport network in terms of latency and bandwidth.

There is now growing consensus that a definition of 5G mobile technology needs to standardize alternative

interfaces to support RAN virtualization. Figure 8 indicates that NTT DoCoMo believes that the 5G architecture

needs to include the standardization of new functional decompositions between the radio equipment and the radio

equipment control, enabling parts of the baseband to be collocated with the PNF.


Figure 8. NTT DoCoMo 5G Virtualization Proposal

Compared with the dedicated optical networks required to support legacy CPRI/ORI decomposition, these new

standardized 5G fronthaul interfaces will be transportable over conventional IP and Ethernet-based transport

networks. In addition to greatly relaxing the fronthaul bandwidth and latency requirements, these new RAN

decompositions can potentially centralize and virtualize most of the intelligence functions in the RAN (that is, MAC

and above), allowing for the access point to be greatly simplified (just RF and PHY layer) and commoditized. Such

simplifications in the access point can help enable wideband capabilities using distributed antenna systems (DAS)

such as access point solutions, which could address the neutral host issues associated with small cells discussed

earlier in this paper. Cisco has been a leader in driving such RAN decompositions and open interfaces in the Small

Cell Forum (that is, the nFAPI interface), starting with 4G LTE and laying the foundation for 5G neutral host small

cells.

The evolution toward new RAN decompositions with open, standardized fronthaul interfaces is also beneficial for

supporting IoT use cases. Whether it is LTE machine-to-machine (LTE-M); narrowband IoT (NB-IoT); one of the

leading low-power, wide-area (LWPA) technologies (such as Sigfox, Long Range [LoRa], Weightless, or OnRamp);

or some new 5G RAT, efforts to centralize and virtualize as much of the RAN as economically feasible help drive

complexity and cost out of the access points for IoT.

The requirements described by industry participants that are driving the definition of the fifth generation of mobile

technologies are increasingly evident to today’s mobile operators. Cisco is not waiting for the definition of 5G to

build capabilities that address the current needs of our customers. Table 3 features six primary areas that make up

Cisco’s RAN strategy and are discussed at a high level in this white paper. These areas are already driving near-

term evolution of our RAN portfolio. Further details about these primary areas are provided in a companion white

paper about Cisco’s strategy for RAN evolution from 4G to 5G.


Table 3. Six Primary Areas of Cisco RAN Strategy

Primary Focus Area Description

Scalable small cell solutions

Recognizing that mobile traffic is shifting indoors and the improving thermal properties of buildings are making them harder to penetrate from the outdoors, Cisco’s RAN strategy is focused on lowering the barriers to massive adoption of indoor small cells. We’ve seen more than 2.5 million deployments of Cisco

® 3G/4G base stations. As

we transition toward 5G, Cisco is set to use primary learnings from these deployments.

RAN virtualization over IP and Ethernet transport networks

With current approaches to RAN virtualization ill-suited to deployment over IP and Ethernet-based transport networks, Cisco has been at the forefront of activities to define a standardized base station decomposition. It will facilitate RAN virtualization that can be transported over nonideal transport networks. This capability offers the opportunity to use in-building LAN/WAN functionality for supporting the virtualized RAN.

RAN automation to drastically lower operational costs

With the proliferation of small cells, the normal management process needs to be automated to enable dramatic reductions in overall network operations costs. With much of these costs associated with RAN optimization, Cisco’s initial focus is on delivering a set of self-optimizing network (SON) tools that dramatically improve the performance of the RAN without the conventional increases in operational costs. Cisco is delivering virtualized services core functionality today and will look to such capabilities to the virtualized RAN. The goal is to right size the supply of RAN services in response to instantaneous demand and delivery.

Vertical value creation through SP Wi-Fi

A carrier-grade network that combines Wi-Fi and small cells provides an innovation platform for service providers and developers to create a range of new monetizable applications and services.

Cisco Connected Mobile Experience, with location-based context-aware information, allows service providers to better engage with their customers through personalized maps, information, offerings, and other services that can be pushed to mobile devices. Shopping malls, stadiums, and resorts are just a few examples of environments where these differentiated, personalized experiences can lead to better customer satisfaction and retention.

Shared network and as-a-service business models

Hosting providers are already using Cisco small cell solutions to offer small cell-as-a-service offerings. These engagements are already supporting the business model transformation highlighted as a 5G requirement by the NGMN Association, enabling third-party hosting providers to use a shared infrastructure to support multiple service providers.

Licensed and unlicensed integration

As a market leader in carrier-class Wi-Fi, Cisco has led the definition of a converged architecture that is able to integrate both licensed and unlicensed radio technologies. Already supporting a standardized 3GPP interface on its residential, enterprise, and service provider Wi-Fi systems, Cisco is enabling mobile operators to simply integrate Wi-Fi into their existing propositions, either as a trusted WLAN access network (TWAN) or using an evolved packet data gateway (ePDG) for Wi-Fi calling integration over third-party Wi-Fi networks. Moving forward, Cisco solutions will enable integration of unlicensed systems into the RAN, using licensed assisted access (LAA) and LTW WLAN aggregation (LWA) technologies.

Core Network Evolution to 5G

Figure 9 indicates several important network-related technologies that are being discussed in the industry for 5G.

NFV, SDN, and network slicing are three primary foundational technologies driving the evolution of the mobile core

network from 4G to 5G. This figure portrays the NGMN Association’s vision for operators for the 5G core network

architecture.


Figure 9. 5G Architecture Vision from the NGMN Association

As discussed, the focus of 5G is on new use cases supporting new vertical markets and enabling new business

models. This is consistent with the NGMN Association view of the operator as shown at the top in the business

application layer. Also discussed in the RAN evolution section of this paper is that LTE-A evolution is also likely to

continue for many years and that there will likely be the introduction of potentially two new RATs to support IoT and

mmWave and massive MIMO technologies. This means there could be three different RATs used as part of 5G to

support the various uses cases and vertical markets envisioned for 5G, as shown in the lower left of Figure 9.

In between the RAN and the business application layer are the infrastructure resource layer (that is, transport) and

the business enablement layer (that is, the core network). Within the core network are various control plane

functions, user plane functions, RAT configuration functions, state information functions for mobility, and so on. If

5G is architected and developed in the traditional nonvirtualized 2G/3G/4G fashion, this would represent a

massively complex architecture. But by using virtualization through NFV and separation of control and user plane

through SDN, this implementation of the architecture can be done in a simpler, more flexible, more efficient, and

less expensive manner to support the many new services expected in 5G.

As an example, Figure 10 shows how the concept of network slicing can be used to simultaneously instantiate

different logical RAN and core network functions to most efficiently support various use cases and verticals. The

flexibility provided by NFV and SDN makes it possible to spin up the different VNFs that implement only the

specific subset of functions required in support of the desired use case or application. For example, a set of VNFs

supporting an outdoor smartphone may only support 3G and 4G RATs and not any of the 5G RATs for IoT or

mmWave. It would support certain control plane and user plane (CP/UP) functions required for mobility, while a

different set of VNFs supporting an IoT application may only support NB-IOT and LoRa RATs with a greatly

reduced set of CP/UP functions that support very limited to no mobility.


Figure 10. Network Slicing Example from the NGMN Association

Cisco has anticipated the need for this type of flexibility as network slicing well before the term network slicing

became associated with 5G. We were a primary contributor to the DÉCOR feature in 3GPP Release-13, which can

support network slicing by enabling operators to deploy multiple logical mobile core networks connected to the

same RAN.

Another critical aspect of the 5G architecture vision shown in Figure 9 is the end-to-end management and

orchestration functions shown on the right. Given the complexities of managing an NFV/SDN-based network,

automation is essential for complex VNF management and orchestration. As shown in Figure 11, orchestration

consists of automation, provisioning, and interworking of the physical and virtual resources used by NFV and SDN.

Cisco’s solution for VNF management and orchestrations is a multivendor, open-source solution based on the NFV

management and orchestration (MANO) architecture. Through this architecture, Cisco can support service chaining

and flexible mobile service steering (FMSS) as defined by 3GPP.


Figure 11. NFV, SDN, and Orchestration

A very important aspect of the 5G core network is that it be access independent to the various RATs that not only

may be introduced by 5G (for example, for IoT or mmWave), but also legacy 2G/3G/4G RATs, WLAN, non-3GPP

based LWPA IoT RATs as well as fixed access technologies. 4G Americas has provided its objectives for realizing

such an access-independent core in Figure 12. The goal represented is to enable a RAN technology-independent

architecture where introduction and connection of new radio technology will be possible in a plug and play manner.

Cisco is already addressing these requirements through the development of an access-independent core that uses

the already defined non-3GPP interfaces (that is, S2a and S2b) to support any access, whether 2G, 3G, or 4G,

WLAN, IoT, fixed access, or any other access that may come with 5G.

Figure 12. Architecture for Access Technology Interfacing


In summary, Cisco’s vision for evolution of the 4G core network toward 5G addresses all of the aspects discussed

in this section, including:

● Integration of SDN and NFV technology to separate user plane and control plane and implementation of

network slicing use cases

● Openness through pluggable multivendor access networks and pluggable multivendor integrated services to

provide a high degree of flexibility and investment protection

● Network slicing, enabling the management of multiple logical networks as virtually independent business

operations on a common physical infrastructure

● Orchestration through automation of VNF management for mobility

Further details about Cisco’s core network vision for the evolution from 4G to 5G are provided in a companion

white paper.

The Internet Evolution to 5G

Over the past decade, the networking research community has made considerable progress in defining the likely

evolutionary direction of the Internet. This definition specifically includes the fundamental architectures and

protocols that will better serve the usage models we have seen and continue to see emerging as the Internet has

matured. Usage models include the proliferation of Internet traffic aimed at distributing digital media and supporting

social networking, e-commerce, smartphone applications, and emergent machine-to-machine (M2M) applications.

Despite the success of IP, it was designed at a time when the fundamental objective of the network was to

transport data packets between fixed communication hosts quickly and efficiently. With packet headers naming the

communication hosts through the same IP addressing scheme used to locate hosts, the network task has been

simply to forward the packets hop by hop from one host to the other. The operational efficiency of routing protocols

has enabled automatic topology mapping and pathology-free routing without significant operator intervention.

In response to the emergence of more elaborate use cases and usage demands (such as mobility, content

distribution, and security), the networking community has incrementally added new functions either as overlays

onto the existing network or as specialized elements in the network to address specific needs. The primary point is

that capabilities considered essential today were not fully appreciated at the time the original Internet design was

conceived. Therefore these capabilities were not incorporated as fundamental elements in the original design.

Thus, over the years the cost of managing and operating the network has progressively increased, in large part

because of the added complexity introduced by the persistent stream of functionality patches and overlays,

including support for mobility.

In addition to the core network evolution discussed in the previous section, the 5G mobile core architecture must

consider the future Internet architecture, in particular network architectures and protocols that implicitly support

mobility, security, and content caching or storage as fundamental components of the network design. Information-

centric networking (ICN) is emerging as a leading architecture that can meet such design criteria. ICN approaches

are focused on the support of future Internet evolution, particularly support of new communication models that

focus on the distribution of information rather than the communication of data packets between endpoints.


Crucial to this work is the rethinking of the major design principles for the Internet to incorporate the requirements

of new application models such as scalable content distribution, mobility, security, and trust as fundamental

architectural design features. Primary networking areas that are included in this work include:

● Naming: Focusing on what content is of interest rather than where it is

● Routing: Based on hierarchical names rather than addresses

● Mobility: Now an intrinsic capability of the networking layer

● Caching/storage: Information may reside anywhere in the network at any time

● Security: Secure content rather than communication channels

As shown in Figure 13, the current Internet architecture centers on the delivery of IP packets between two

endpoints through the minimal functionality necessary to provide connectivity globally. Further, the Internet of today

is based on a host-based conversation model, allowing many geographically distributed users to access mainly

statically located content. The thin waist shown in the figure has enabled the graceful evolution of the Internet by

allowing innovation in the upper and lower layer protocols and technologies to proceed independently. However,

the need to apply the location-oriented addressing model of IP to Internet usage patterns increasingly dominated

by highly mobile devices such as smartphones and tablets has proven to be a continual challenge.

Figure 13. Contrasting Focal Points of ICN to the Current IP-Centric Internet

ICN enhances the role of the networking layer, replacing its task from simply providing a pairwise packet delivery

channel between communicating hosts to delivering named information to an endpoint that expresses an interest in

it without explicit direction as to where that content is stored. By operating on named objects at the network layer,

ICN facilitates the deployment of in-network caching and storage in general. It simplifies multicast and enables a

security model where individual content objects are secured rather than the channel over which they are conveyed.

Expressions of interest, implemented through a request-response mechanism, support mobility and congestion

control and avoidance mechanisms implicitly. So the need for an overlay to support mobility may be avoided. The

strategy mechanism provides a flexible means to realize intelligent, context-aware control of content storage and

delivery. Figure 14 demonstrates this evolution to an information-centric network from the packet switching 4G

networks and circuit switching 2G/3G networks of today.


Figure 14. Evolution of the Network from Circuit-Centric to Packet-Centric to Information-Centric

As an example, Figure 15 shows the three main components of an ICN architecture: the forwarding information

table (FIB), the pending interest table (PIT), and the content store. While the current IP-based Internet is based

primarily around forwarding and the FIB tables, an ICN-based Internet adds to this content storage along with

pending interest information. There are two types of packets in ICN: interest packets and data packets. An interest

packet is a request for information, but based on the content of the information and not the IP address of the

information. For example, an ICN interest packet request could be something like /conference/paper/NDN.pdf.

Based on this request, the first ICN router will look to see if the content is in its cache. If so, then it returns the data.

If not, then it looks in the PIT to see if there has already been a request for this information. If so, then the incoming

interface is added to the PIT so that when the content arrives it will be sent to the requester. This allows interests to

be aggregated whenever multiple interests for the same content are received while the first is still waiting for its

data to be returned. When the data is received, it is multicast over the aggregate of faces that interests were

received on. ICN employs a symmetric transport model in which each data packet is returned over the same path

traversed by the interest packet that requested it. This basic design feature enables support for many useful

capabilities such as mobility, multicast delivery, hop-by-hop congestion control, and flow balance as emergent

properties of the architecture.

Figure 15. Focal Points of ICN Compared to the Current IP-Centric Internet


These basic concepts being explored in the ICN and CCN community have direct relevance to the design of the 5G

core network and can result in significant simplification. It will serve the cellular community well to carefully study

this work to understand how it can be used for 5G and how it can be shaped to better serve longer-term cellular

industry interests. The basic principles may serve to alter the evolutionary path of the current cellular core and

enhance the role of the service provider in the information delivery economic chain. More details about ICN and its

influence on the evolution of the 5G mobile core architecture are provided in a companion white paper in this

series.

Conclusion

While operators will ultimately determine what gets marketed as 5G, the ITU IMT-2020 process is providing

guidance for the industry in defining requirements to meet the use cases, new vertical markets opportunities, and

new business models that must be addressed by mobile operators. It is clear from early discussions that these

requirements cover a very broad range of use cases. On one end of the spectrum, there is the need for continued

increases in capacity and throughput for mobile broadband access. While complex technologies related to

mmWave, massive MIMO, and new RATs will be a part of 5G, the need for less complexity, lower cost, and neutral

host small cells must also be a focus for 5G to meet the exponentially growing mobile data usage trends.

Cisco is leading the effort to develop an ecosystem around a new C-RAN interface to address the operational

expenditure challenges of 3G/4G small cells and to pave the way for 5G to enable a more densified, lower TCO

RAN. On the other end of the spectrum is the need for low throughput with very wide coverage and low-cost

solutions for IoT applications. Cisco is already executing on the 5G vision toward building a more flexible and

scalable mobile core network that can support network slicing and is access independent through early

development of primary features such as DÉCOR, whose standards Cisco was integral in championing. Finally,

Cisco is leading the way for 5G Internet standards to encompass ICN, a new paradigm addressing the needs of

modern Internet usage with mobility, security, and storage as the foundations.

For More Information

For more information about the topics discussed in this white paper:

Universal Wi-Fi for Service Providers: http://www.cisco.com/c/en/us/solutions/collateral/service-provider/service-

provider-wi-fi/white-paper-c11-733136.html

Fair Co-Existence of Licensed Assisted Access LTE (LAA-LTE) and Wi-Fi in Unlicensed Spectrum:

http://www.realwireless.biz/realwireless/wp-content/uploads/2015/09/Fair-Co-Existence-of-LAA-and-Wi-Fi-V1-1.pdf

Secure Wi-Fi Offload for Untrusted Networks: Cisco ePDG Evolved Packet Data Gateway:

http://www.cisco.com/c/en/us/products/collateral/wireless/asr-5000-series/white_paper_c11-707739.html

Multipath TCP and Product Support Overview: http://www.cisco.com/c/en/us/support/docs/ip/transmission-control-

protocol-tcp/116519-technote-mptcp-00.html#anc1

http://www.cisco.com/c/en/us/solutions/collateral/service-provider/service-provider-wi-fi/white-paper-c11-733136.html

http://www.cisco.com/c/en/us/solutions/collateral/service-provider/service-provider-wi-fi/white-paper-c11-733136.html

http://www.realwireless.biz/realwireless/wp-content/uploads/2015/09/Fair-Co-Existence-of-LAA-and-Wi-Fi-V1-1.pdf

http://www.cisco.com/c/en/us/products/collateral/wireless/asr-5000-series/white_paper_c11-707739.html

http://www.cisco.com/c/en/us/support/docs/ip/transmission-control-protocol-tcp/116519-technote-mptcp-00.html#anc1

http://www.cisco.com/c/en/us/support/docs/ip/transmission-control-protocol-tcp/116519-technote-mptcp-00.html#anc1


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