Software Defined Networks (SDN)

How to get maximum performance out of your IT infrastructure

IT managers have been preoccupied with virtualising their corporate IT for many years. After the cloud, workplaces and telephony, they are now focusing on their networks. This specialist article describes how IT decision-makers should go about it using SDN-based network architectures.

First published on 25 january 2019, updated 16 march 2020

Data, storage space, and apps, etc. are already in the cloud. They can be accessed on smartphones, tablets or notebooks as well as business applications like payment systems and M2M applications. As you know, IT already offers these possibilities.

However, you also know that the more you have connected to your network, the greater the demand for performance, stability and scalability. What you therefore need is a network that is highly elastic so that it can react flexibly and in an agile manner to changing business requirements.

SDN-based network architectures meet all these requirements in full. They do so by replacing many network components with central software applications and a handful of standardised hardware components. Rather than lots of proprietary and dedicated hardware, as many functions as possible are virtualised and realised as software. This enables you to respond quickly and easily to change.

Software-defined wide area networks (SD-WANs) are an automated and extremely cost-effective approach to the management of corporate networks. They use programmed network elements that employ dynamic routing to remotely define the best path and optimise it for the relevant application.

SD-WANs determine the optimal path based on the network conditions, the security and QoS (quality of service) requirements of the entered application data traffic and the cost of the connection. SD-WANs react proactively to real-time network conditions. Consequently, the business benefits from optimised costs, greater agility and improved performance.

An end-to-end perspective

Central and transparent end-to-end management helps execute customer wishes across network or national boundaries. SDN solutions like Enterprise Connect from Swisscom offer the necessary platform. Three goals are primary in this respect:

The centralisation of resource and network management facilitates the everyday work of administrators. What’s more, uniform orchestration takes over the configuration and monitoring of all network elements. It communicates with the individual components of the services via APIs that autonomously report their status and errors to it. This orchestration provides an end-to-end perspective of the network, right down to the network element level. As a consequence, sources of errors can be identified and rectified quicker.
The configuration of networks and services is coordinated rather than accessing individual components such as routers, switches, firewalls and access points separately, as was the case in the past. Thanks to SDN, “on-demand” configuration is faster and results in fewer faults because the overall perspective of the network automatically takes account of the interdependencies of individual systems. This far-reaching automation enables new applications and services to be rolled out far faster and simpler than before.
The integration of third-party providers (e.g. AWS, Azure and SAP) can be defined in a customer-specific manner via the SDN platform. Additional services can be added simply, quickly, seamlessly and with the accustomed security at the touch of a button via a dashboard.

The SDN controller as the central architectural element

Virtualising network resources enables rapid adaptation to changing business conditions, applications or momentary data traffic volumes. This is made possible because the control layer is kept separate from the infrastructure (data) layer. Network-wide monitoring and control functions are bundled within the SDN controller. With the aid of software, this creates a programmable infrastructure that is more independent of the physical devices.

SDN controllers use open standards and APIs, thus enabling the orchestration, control and management of network devices from different manufacturers. This takes place at the application layer, which offers individual perspectives of the infrastructure. Based on open platforms, the application layer capitalises on the scalability, performance and availability of modern cloud computing and storage resources.

As a result, new services or locations can be ordered from Swisscom via order management within minutes rather than weeks or even months.

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Whitepaper

With SD-WANs into the Hybrid Cloud

The whitepaper explains the functionality of a SD-WAN and describes application possibilities in the field of cloud connectivity.

Virtualised network functions for routers, firewalls and the like

SDNs and SD-WANs are closely related to network function virtualisation (NFV). Application-based network functions, such as routers, firewalls and load balancers, are virtualised. Thanks to NFV, all monitoring and controlling functions can be handled by the SDN controller in the control layer.

NFV uses cloud and virtualisation technologies to enable rapid development of new network services with flexible scalability and automation. It also enables virtual network functions (VNFs) to be added to the SD-WAN. Virtual network services like virtual private networks (VPNs), firewalls, QoS and multicasting can also be operated on the same virtual CPE platform alongside the SD-WAN.

In this way, new services can be made available far more quickly, with fewer faults and in a demand-oriented manner, which clearly helps meet the aim of improving agility and scalability.

Network and service management reduced to three layers

Up to now, network and service management tended to be rather complex and difficult. Central SDN controllers avoid network complexity and combine the local network elements. This is achieved by separation into three layers:

The control layer
The infrastructure layer
Orchestration at the application layer

This increases the flexibility and agility of the individual layers as well as the scalability of the entire system.

An example: Up to now, you have deployed specialised and proprietary hardware like switches and firewalls. But you don’t need them anymore. Instead, you can use cheaper universal hardware and assign it the relevant required role using software. As such, a hardware element can be used as a load balancer one day and as a firewall the next day – provided that it has been supplied with the necessary software function from the cloud.

The separation of network functions into manageable units and the division into three clearly defined layers also has a positive impact on security. After all, businesses using SDN can cut their operational expenditure because simpler programmability means that network functions can be automated more easily.

Outlook

In future, the flexible opportunities offered by SDNs will not be restricted by national boundaries. Interconnecting the SDN controllers of different network operators offers a seamless solution for international customers. If you woud like further information, we recommend our white paper “With SD-WANs into the Hybrid Cloud”.

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