A new way to create and manage long-distance networks
Everything is going to software these days, including network technology. Unlike traditional networks where decisions are made in the firmware of the equipment, software-defined networking (SDN) uses network abstraction to separate the data and control planes, which means that the task of network administration becomes much more dynamic and flexible. But while SDNs are generally focused on local area networks, SD-WAN offers dynamic and scalable connectivity over long-distance networks. It is a major step in the evolution of networking capabilities.
A Paradigm Shift
Computers communicate with each other through complicated interconnected systems known as networks. A network infrastructure could be a local area network (LAN) or a wide area network (WAN). While a LAN may serve a building or campus at a single location, a WAN is a network that extends across long distances — even to the other side of the world. Traditional networks are composed of dedicated equipment, such as switches, routers, and firewalls that are controlled by instructions from internal firmware.
Software-defined networking changes all that. The paradigm shift in networking parallels a similar change in operating systems. Instead of a fully functional computer with an operating system and applications, a virtual machine is an emulation of the hardware that instead exists as software. This move to software has been taking place in practically all areas of computing, including storage, database management, and memory.
The local network was the first to get this kind of treatment in the networking world. Michael Cooney of NetworkWorld explains it this way:
“Hardware reigned supreme in the networking world until the emergence of software-defined networking (SDN), a category of technologies that separate the network control plane from the forwarding plane to enable more automated provisioning and policy-based management of network resources.”
The idea of using software rather than hardware to manage networks is all about programmability. While firmware instructions in hardware are fairly static and often depend on scheduled maintenance windows for alteration, software-based networks are flexible and dynamic and can be changed on the fly. At first, this new development was limited to LANs in the form of software-defined networking (SDN). Now the same concepts and principles that liberated operating systems, storage, and LANs have been applied to long-distance networks. The result, known as SD-WAN, appears to be the perfect fit for today’s cloud-centric digital world.
SDN as a Precursor to SD-WAN
To get an idea of the potential for SD-WAN on long-distance networks, let’s have a look at how SDN is already having an impact on local networks. The following are all press releases from my company DASAN Zhone Solutions, a telecommunications networking provider:
- In September 2018, we explained how our DZS M3000 transport switch would take advantage of the network slicing capabilities of SDN to segment 5G wireless traffic and enhance efficiency for the South Korean telecom operator LG U+
- In October 2018, we told the world about enhancements to our Passive Optical Network (PON) portfolio that expand broadband service options with increased SDN features on our 100 Gbps switches
- In January 2019, we announced a new generation of FiberLAN distributed switches and port extenders, including the DZS FL-108 Series hardware, which leverages SDN to enable Intent Based Networking and auto-provisioning (rather than expert switch configuration)
- In March 2019, we reported that 11,000 South Korean schools have chosen to use our SDN-based solutions to consolidate network management and improve productivity.
The Benefits of SD-WAN
The good thing is that what SDN does for the LAN, SD-WAN will do for the WAN. (You might think of SDN as “SD-LAN”.) A significant benefit of SD-WAN is that you can build a network and throw everything into it. When you put all your network into software, you are essentially abstracting all the intelligence of the network and unifying it into a centralized control system. What used to require tedious command-line configuration on multiple devices can now be accomplished with a few points and clicks on a single screen.
The control plane of a network tells data — held in the data plane — where it should go. This function no longer needs to be locked up in each device across the network. No more do network engineers have to configure routing changes on every router, for instance. This has always been a cumbersome, time-consuming task. SD-WAN simplifies everything.
Imagine you have 100 routers in your network that — because of a recent network redesign — all require changes in the way that they forward data packets. Even with scripts and automated processes, this can be a big job. Now imagine that you are able to use a single computer screen to group and modify your 100 routers according to their required changes. Game changer.
The orchestration of long-distance networks with SD-WAN is made possible through the creation and application of rules, or policies. These policies allow network managers to quickly and easily direct traffic according to packet type, destination, or some other criteria. The ability to finely control the forwarding of data between devices in a network is at the heart of software-defined networking.
5G and SD-WAN
These changes do not occur in a vacuum. At the same time that software is taking charge of networks, other important things are happening in information technology. The advent of 5G wireless, for example, lends itself as a prime candidate for SD-WAN use cases. I discussed in a previous post how 5G will change the world through greater bandwidth, higher speeds, and less interference. But what happens if you combine the power of 5G with the innovation of SD-WAN?
When I looked at the historical progression of wireless networking, I mentioned that mobile data usage is expected to grow exponentially in the next few years, with the prospect of billions of connected devices in the vast Internet of Things (IoT). This mobile revolution brings with it the need for greater network agility to process so many resources in a timely manner.
Network marketing expert Francisca Segovia suggests that SD-WAN may be the “super-glue” that brings all these 5G edge devices together. She writes:
“An SD-WAN platform that enables automation will help service providers to easily connect to and integrate across all the different compute edges required to optimize the traffic and management of 5G cells. This will enable a seamless transition towards a full 5G infrastructure by managing any transport available across the edge, leveraging 5G transport for those critical applications that require zero latency and higher speeds.”
It looks like 5G and SD-WAN are a marriage made in heaven. Something has to manage all that traffic, and it’s no longer possible to trust firmware-based equipment with that mission. SD-WAN is the future of wide area networks.
What Else Can SD-WAN Do?
Potential uses for SD-WAN are vast. Some descriptors come to mind: agile, flexible, dynamic, adaptable, extensible. Its expansive power comes from the programmable nature of SD-WAN networks. Just as general purpose computing lent itself to so many different uses, SD-WAN network designers will find that the possibilities are only limited by their imagination.
Uses cases for SD-WAN might include:
- Branch office connectivity through the cloud
- Simplified WAN management
- Dynamic path optimization
- Cloud application deployment
- Distributed cloud security
- Network-as-a-Service (NaaS)
- Enhancement of manufacturing processes
- Improved security for financial systems
- Healthcare monitoring and management
SD-WAN is a software-based approach to wide area networks — essentially a virtual WAN. It can be used to connect any application using any connection technology, whether MPLS, 4G, 5G, or broadband internet. SD-WAN offers quality-of-service controls to differentiate traffic in multiple ways, and it offers business-driven solutions for challenges such as latency, configuration, and performance. While SD-WAN will build on the past successes of more mature technologies like SDN and WAN, it may hold the key to the promising future of our vast and growing global network ecosystem.