SDN Versus Traditional Networking Explained

By IBM Services

What are the benefits of SDN and how is it different from traditional networking?

When it comes to creating their own networks, every enterprise has to weigh the pros and cons of the different network types. With increased consumer demands for performance and flexibility, some cons quickly become heavier than others.

Along with the growing needs of modern networks, the biggest cons of maintaining traditional networks have bolstered the ascendancy of software-defined networking (SDN). SDN and other virtualized solutions are burgeoning. Globe Newswire argues that the SDN market will reach USD 59 billion by 2023

Physical infrastructure, especially hardware that requires manual configurations, simply hasn’t been able to keep pace with modern technology. The ballooning demands that modern enterprise users require are too much for most traditional networks. Users looking to upscale their network infrastructures with as little disruption as possible quickly turn to SDN.

What’s SDN?

SDN is defined by “the decoupling of control and packet forwarding planes in the network”.² It enables networks to directly connect to applications through application programming interfaces (APIs), bolstering application performance and security, and creating a flexible, dynamic network architecture that can be changed as needed.

Arguably, the most frequently used means for application deployment, SDN is used by enterprises to deploy their applications faster while also cutting the overall deployment and operating costs. IT administrators using SDN can manage and provision their network services from a centralized point.

A network paradigm that yields programmatic management and control, and network resource optimization, SDN applies open APIs to help maintain network control. This network control is created when SDN decouples the network configuration and traffic engineering, separating them from their fundamental hardware infrastructure.

This parting allows the use of OpenFlow and other open protocols. These open protocols can access network switches and routers that often use proprietary and otherwise closed firmware by applying globally aware software control at the network’s edge.

The control plane and the data plane, and early SDN implementation

SDN helps users virtualize their hardware and works to create a computer network by breaking down the network into the following separate planes:

  1. The control plane offers the performance and fault management of NetFlow and, like protocols, is frequently used for managing device configurations that are remotely connected to a software-defined network.
  2. The data plane forwards traffic to its desired destination. Before traffic reaches the data plane, the control plane dictates what path flows it will take by using the flow protocol— when a network administrator works with the software-defined network and manages the network.

When it was first deployed by large enterprises, such as Google and Amazon, SDN helped them create scalable data centers, facilitate network resources and new server expansion, and reduce the workload for IT administrators. SDN optimized the efficiency of the upscaling process for these large companies and quickly drew the attention of other large companies who swiftly adopted SDN to improve their upscaling efficiency.

What is a traditional network?

Traditional networking is rooted in fixed-function network devices, such as a switch or router. These devices each have certain functions that operate well together and support the network. If the network’s functions are implemented as hardware constructs, then its speed is usually bolstered.

Flexibility is a recurring hurdle for traditional networks. Few APIs are exposed for provisioning and most switching hardware and software is proprietary. Traditional networks often work well with proprietary provisioning software, but this software can’t be quickly modified as needed.

Traditional networking consists of the following traits:

  1. The functions of traditional networking are primarily implemented from dedicated devices, using one or more switches, as well as routers and application delivery controllers.
  2. The functionality of traditional networking is largely implemented in dedicated hardware, such as application-specific integrated circuits (ASIC). One of the negative aspects of this traditional hardware-centric networking is its limitations.

What are the differences between SDN and traditional networking?

The most notable difference between SDN and traditional networking is that SDN is software-based while traditional networking is usually hardware-based. Because it is software-based, SDN is more flexible, allowing users greater control and ease for managing resources virtually throughout the control plane.

Inversely, traditional networks use switches, routers and other physical infrastructure to create connections and run the network.

SDN controllers feature a northbound interface that communicates with APIs. Because of this communication, application developers can directly program the network, as opposed to using the protocols required by traditional networking.

SDN lets users use software to provision new devices instead of using physical infrastructure, so IT administrators can direct network paths and proactively arrange network services. Unlike traditional switches, SDN also has the ability to better communicate with devices using the network.

Virtualization epitomizes the primary difference between SDN and traditional networking. When SDN virtualizes your entire network, it generates an abstract copy of your physical network, and lets you provision resources from a centralized location.

Opposingly, with a traditional network the physical location of the control plane hinders an IT administrator’s ability to control the traffic flow.

With SDN, the control plane becomes software-based, allowing it to be accessed through a connected device. This access lets IT administrators manage traffic flow with greater detail from a centralized user interface (UI). This centralized location grants users greater control over how their networks work and how their networks are configured. The ability to quickly process different network configurations from a centralized UI is especially beneficial for network segmentation.

SDN became a popular alternative to traditional networking because it lets IT administrators provision resources and bandwidths as needed without requiring an investment of additional physical infrastructure. Traditional networking requires new hardware to increase its network capacity. The paradigm for SDN versus traditional networking could be distilled to the generalization: one requires more equipment for expansion and the other requires only keystrokes.

What are the primary advantages of software-defined networking?

Software defined networking has the advantage of generating a framework that bolsters data-intensive applications, such as big data and virtualization. Big data and virtual machines are somewhat intertwined. Ingram Micro argues that “Virtualization adoption is being driven by big data and SDN provides the means to manage virtual machines and big data network traffic.”³

In addition to centralizing and simplifying the control of enterprise network management, SDN offers the following succinct advantages:

  • Traffic programmability
  • Greater agility
  • Capacity to generate policy-driven network supervision
  • Ability to implement network automation

Here are several of the primary advantages that SDN offers:

  1. Centralized network provisioning. SDN helps centralize enterprise management and provisioning by offering a unified perspective on the whole network. SDN can also speed up service delivery and boost agility in provisioning virtual and physical network devices in a central location.
  2. Holistic enterprise management. Networks must meet the rising demand for processing requests. SDN helps your IT department adjust your network configuration with no impact on your network. Also, unlike Simple Network Management Protocol (SNMP), SND bolsters the management of physical and virtual switches and network devices that are from a central controller.
  3. More granular security. Virtual machines pose a challenge for firewalls and content filtering, a challenge that’s further compounded by personal devices. By establishing a central control point for regulating security and policy information for your enterprise, the SDN controller quickly becomes a boon for your IT department. 
  4. Lower operating costs. Several benefits to SDN, such as having an efficient administration, server utilization improvements, and improved virtualization control, can dually help cut operating costs. Because many regular network administration issues can be automated and centralized, SDN can also help reduce operating costs and grow administrative savings. 
  5. Hardware savings and reduced capital expenditures. SDN adoption helps revive older network devices and simplifies the process of optimizing commoditized hardware. By following the instructions from the SDN controller, older hardware can be repurposed while less costly hardware can be deployed to optimal effect. This process allows new devices to become veritable “white box” switches that have intelligence focused at the SDN controller.
  6. Cloud abstraction. Using SDN to abstract cloud resources helps simplify the process of unifying cloud resources. SDN controllers can manage all the networking components that comprise the massive data center platforms.
  7. Consistent and timely content delivery. One big benefit of SDN is the ability to manipulate data traffic. It’s easier to have quality of service for Voice over Internet Protocol (VoIP) and multimedia transmissions if you can direct and automate data traffic. SDN also helps with steaming higher-quality videos since SDN bolsters network responsiveness and, therefore, creates an improved user experience (UX). 

Why are companies transitioning to SDN from traditional networks?

In addition to its many benefits, here are several other reasons why data enterprises are opting for SDN over traditional networking:

  1. Today’s users demand the untethered access to infrastructure, applications and IT resources. This demand comes as a result of the proliferation of cloud services, which necessitates additional storage, computing and bandwidth.
  2. The advent of bring-your-own-device in the workplace requires dynamic and flexible networks. These networks must also be security rich and capable of protecting data and assets, and meeting compliance regulations and standards. Because it adheres to product cycles and vendor-specific environment proprietary interfaces, traditional networking is unable to meet these demands. Traditional networking tends to be rigid, making it difficult for network operators and administrators to customize the programming of their networks. The process of adding devices or increasing network capacity is cumbersome and time-consuming, necessitating hands-on access for each console and device.
  3. SDN lets network operators and administrators adjust their resources and bandwidths as needed, providing data centers with boosted efficiency, malleability and resiliency. Also, SDN doesn’t require investing in physical infrastructure and isn’t largely capable of being automated, which further bolsters the chances of enterprises to cut costs and improve network performance.

SDN versus SD-WAN

Because of their similarities, SDN is often compared with software-defined wide area networks (SD-WANs). By using broadband and Multiprotocol Label Switching (MPLS), SD-WAN lets enterprises connect different locations. SDN is meant to function on local area networks (LANs) and is used for creating networks that can be speedily modified as needed. SD-WAN is meant to produce a wide area network (WAN) that links several sites together and support a WAN for a broad geographical spread.

Similar to SDN, a SD-WAN eliminates the need for maintaining lots of network hardware. Additionally, a SD-WAN can be used from an software-defined network where it offers the geographical capabilities of a SD-WAN along with the flexible capability of SDN to be configured as needed.

Also, SDN is configured by the IT administrator or the user, while vendors control a SD-WAN service. Because users aren’t responsible for offering the service, an SD-WAN tends to be easier to deploy.

IBM SDN with Cisco ACI

IBM can help

For anyone looking to get started on the journey to the cloud, SDN can be a key component that helps you transform your sluggish network into a nimble connector. IBM can help your enterprise break free from its cumbersome hardware constraints and gain improved agility, security, flexibility and programmability.

With a consulting-led approach that helps build cloud-enabled, dynamic, resilient networks for your future business needs, IBM SDN Services provides offerings that are customized for your enterprise.

IBM SDN services helps enterprise customers create a highly programmable network spread that stretches through data center and cloud software-defined network-data center (SDN-DC), wide area network SD-WAN and branch networks (SD-LAN).

For more information about SDN and how it can help your business, schedule a one-on-one meeting with an IBM expert at no cost. IBM is here to help you move your business forward with confidence.

  1. “Software Defined Networking (SDN) Market Size USD 59 Billion by 2023 Growing at Massive CAGR of 42.41%” Globe Newswire, April 4, 2019.
  2.  “SDN vs Traditional Networking: Which Leads the Way?”. Fiber Optic Cable Solutions, December 22, 2018.
  3. “7 Advantages of Software Defined Networking.” Ingram Micro, August 8, 2017.