Network Architecture
Mokhtar Hossam Hosny Hassan
1808188@eng.asu.edu.eg
Network Architecture: SDN and its evolution
• SDN is a network architecture that breaks the vertical integration in traditional networks to
provide flexibilty to program the network through centralized network control.
• It separates the control plane and the data plane in which the control plane is centralized at a
set of SDN controllers, while the data plane is simplified to for network applications and
services requesting through the SDN controllers.
• SDN is also divided into 4 planes ( Data, Control, Application and Management and
Adminstration Planes) like in Figure1.
• Data plane
• forward and route the data packets to the SDN controllers according to the instructions made
in the controller plane via data-controller plane interface (D-CPI)
• Control Plane
• Translating the applications’ requests and take more control over the network elements.
• It acts as the bridge between the Data plane and Application plane.
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Network Architecture: SDN and its evolution
• Application plane
• consists of applications and communicates their requirements towards the controller plane via
Application-controller plane interface (A-CPI)
• Management and Adminstration plane
• Responsible for provisioning and monitoring the network
Figure(1) SDN components
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Network Architecture: SDN and its evolution
• The SDN architecture is programmable, agile, and cost effective and used to to enable 5G to
function across a control plane and better data flows for data moving across the 5G network.
• However, there are som challenges in terms of deployment, Reliability, security and etc.
• Deployment
o SDN deployments will incur considerable cost in the initialized equipment transformation
and professional training. 5G networks will inevitably increase the complexity of SDN
design and deployment.
• Reliability
o To guarantee uRLLC in 5G, a fast and expensive out-of-band wide area network between
SDN controllers and switches will be needed.
• Security
• Because SDN controllers are logically centralized and run on Windows or Linux operating
systems, the risk of being attacked or failures will also increase.
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Network Architecture: NFV and its evolution
• NFV is a network architecture where network functions are implemented in software that runs
on top of general-purpose hardware such as high volume servers.
• It transforms the network functions originally implemented on dedicated hardware.
• A high-level overview of the NFV architecture is shown in Figure (2) is consisted of 3 main
parts:
1. NFV infrastructure (NFVI): provides the necessary virtual resources to support the
execution of VNFs.
2. NFV infrastructure (NFVI): is the network function implemented in software running
over the NFVI
3. NFV management and orchestration (NFV M&O): covers the orchestration and lifecycle
management of physical and software resources supporting the NFVI, and also the
lifecycle management of VNFs.
• NFV is a key enabler for 5G, which helps to virtualize the various appliances in the network,
also it will enable virtualization of cloud RAN, which will help to deploy the networks and
reduce the capital expenditure
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Network Architecture: NFV and its evolution
NFV will provide infrastructure for network slicing, which permits a physical network to be
separated into multiple virtual networks to support different RANs or various services.
• However, the M&O of SDN and NFV is still an open challenge in 5G and 6G, which faces the
complexity, reliability, security, and multitenant issues.
•
Figure(2) NFV components
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Network Slicing and its improvement
• Network slicing is a network architecture that enables
the multiplexing of virtualized and independent logical
networks on the same physical network infrastructure.
• A network slice is a logically isolated end-to-end network
that is tailored for a particular service type with agreed upon
service-level agreement.
Figure(3) Network Slicing
• The network slicing concept mainlyconsists of three layers as in figure(3):
1. The service instance layer: represents a service provided by the network operator or
third party.
2. The network slice instance layer: provides the service instance with the required network
characteristics and it may be fully or partly, logically and/or physically, isolated from
another network slice instance.
3. The resource layer.
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Network Slicing and its improvement
• Each network slice may contain zero, one or more sub-network instances, which may be
shared by two or more network slices.
• A sub-network instance can be a network function running on the physical/logical resources
• Different slice types are defined in:
1. eMBB
2. mMTC
3. uRRLC
• Network slicing is based on SDN and NFV and thus inherits most of the problems and
challenges from them in addition to some additional considerations that must be addressed in
future 6G such as:
1. Slice Isolation.
2. Dynamic slice creation and management.
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SBA and its evolution
• SBA has been introduced for 5G core network to meet the diverse requirements of services and
introduce new services.
• The core network in case of SBA consists of:
1.
2.
3.
4.
5.
6.
7.
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9.
The authentication server function (AUSF):
Extensible authentication protocol (EAP)
The access and mobility management function (AMF)
Session management function (SMF)
The policy control function (PCF)
The user plane function (UPF)
The unified data management (UDM)
The application function (AF)
Network repository function (NRF) and Network Exposure Function (NEF)
Figure(4) SBA for 5G core network
• The SBA is based on cloud computing, virtualization, microservice, stateless service, etc.
• The SBA introduces the set of security features in 5G and 6G that enable network functions of the
SBA to securely communicate within the serving network domain and with other network domains.
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CSA
• The CSA has two features:
1. It can accurately recognize target behaviors and user characteristics.
2. It adjusts the network services adaptively and dynamically through the unified service
description method.
• These features are supported by a cognitive interface, the lightweight learning agent, and the
distributed service analyzing module.
1. With the cognitive interface, the 6G core network has the ability of situation cognition
and can perceive the change of service demand in a very fine-grained way.
2. The lightweight learning agent makes the decision according to gained information by
rule matching or approximate reasoning.
3. The distributed service analyzing module evaluates the service running state and
provides a reference for the decision making of a lightweight learning agent.
•
With CSA and edge core, 6G core network will leverage edge computing to form a multicenter architecture to provide efficient, flexible, ultra-low delay, and ultra-large capacity
network services.
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CSA
• CSA will realize the whole network coverage from the core network to the UE.
• In this CSA enhanced by edge AI, 6G will further evolve from current “human-machine-thing”
interactions to “human-machine-thing-genie” interactions.
• These new ubiquitous, social, contextual, consciousness-based communication and control
scenarios require intelligent service coordination of the real world and virtual world, as well as
the efficient collaborative computing of various end devices and network nodes.
• With the help of such intelligent and collaborative computing scheme, the 6G network can
fully provide the ubiquitous immersive IoE services, including virtual scenarios and real
scenarios by sensing various types of objective and subjective information.
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