Legacy WAN Vs SD-WAN: The Big Software Defined Difference

Wide area networks (WAN) are hardly new, so do you really need to sit up and take any notice with all the fresh talk about software-defined WAN? Actually, the story is pretty compelling. Software-defined WAN (SD-WAN) is changing the network landscape in exciting ways.

‘It’s just the way we’ve always done it’

Before we jump into the exciting new developments, it’s worth a cursory refresher on what SD-WAN is replacing. Historically, wide area networks relied on dedicated private links, leveraging technologies such as frame relay, Asynchronous Transfer Mode (ATM), Multiprotocol Label Switching (MPLS) or Virtual Private Networks (VPN) delivered under a dedicated carrier contract.

Setting up a legacy wide area network, such as MPLS, to connect your distributed offices typically involved approaching a telecommunications carrier like Telstra to say “We need connectivity between ‘this many’ sites and we need about ‘this much’ bandwidth. Tell us how much that will cost per month.”

That whole model is based on your physical network and a framework to connect remote sites back to a central data centre. The rigid structure of dedicated legacy networks made sense in the past when remote sites primarily relied on accessing data and apps in that central data centre. The difficultly today is that legacy WAN is increasingly expensive to maintain and presents a number of other challenges in an evolving data environment.

For example, legacy MPLS networks offer limited visibility into network traffic to enable you to know what is actually happening on the network at any given time. Combine that with changing data demands arising from the fact that remote offices now access and generate data in vastly different ways – organisations are far less reliant on one central data centre. Data is far more likely to be distributed throughout the organisation and across the cloud – which is where software-defined networks come into their own.

There is a better way

SD-WAN takes a different approach to network connectivity that lowers operational costs and improves resource usage for multi-site deployments. Instead of focusing on the physical locations and the cables between them, SD-WAN enables network administrators to use an abstracted management layer on the cloud to manage bandwidth more efficiently and ensure the highest possible level of performance for critical applications without sacrificing security or data privacy.

Sounds fancy, but what does it actually mean? Well for starters it means that with a software-defined WAN you can now manage data flows over multiple pathways including the internet and cellular networks, in addition to your legacy MPLS network. With a software-defined network, decisions about how traffic can route between sites is defined by policy rather than cables, so network behaviour can adapt to the condition of the WAN as opposed to having a fixed configuration. For example, automated load balancing across those multiple pathways can adapt to varying data flows, and automatic failover to alternate pathways can maintain service delivery when something goes wrong elsewhere on the network. Cloud-first network infrastructure like Cisco Meraki access points, switches and routers enable this software defined approach out of the box. Designed from the ground up to leverage cloud connectivity, the technology offers infinitely more flexibility for network administrators while increasing bandwidth in order to deliver significantly improved network performance, which is what end users care about.

SD-WAN overcomes the high cost of legacy enterprise WAN by connecting remote sites over lost-cost internet links secured by VPN. Network reliability is enabled by load balancing across an array of uplinks and down links combined with intelligent path control to re-direct traffic across the most efficient pathway. If you compare this ever-evolving dynamic management to the fixed physical map metaphor of a legacy WAN, SD-WAN with Meraki is more akin to Google Maps: if the traffic ahead gets heavy, Google simply changes your directions to take you on a lower traffic alternative to get you home faster.

With a Meraki software-defined WAN, intelligent path control means you can used policy-based routing to assign track paths based on the source of the data (e.g. prioritise data from this primary datacentre), or destination (e.g. prioritise data to optimise online service for these customers), or application (e.g. prioritise this call centre operations application to maximise responsiveness).

It also means that dynamic path selection can be used to ensure network performance remains under specified loss, latency and jitter thresholds that can even be specified per application. So, if network constraints at a point in time force a choice, your pre-defined network management policies can automatically kick in to prioritise network resources for a business-critical application over and above end user access to social media applications.

That subtlety and granularity means you can deliver far more reliable network performance at a fraction of the cost of legacy WAN approaches.

It is remarkably easy to make a start

The promise is clear and attractive, but is the path to get there worth the effort? In fact, it is gratifyingly simple. Simplicity is at Meraki’s core because everything is connected to the cloud which enables smart remote set-up every step of the way. During network configuration, devices are dynamically connected, and the entire network can be templated across sites allowing simple roll out. The cloud-based management platform means administrators can run all sites from a single cloud portal, so if a change is made to a particular setting, it can easily be rolled out across the entire network.

• Configure wireless network settings in cloud dashboard
• Plug in a Meraki access point and it automatically pulls those settings
• Throttle bandwidth or block applications through a cloud dashboard
• Streamline device onboarding with built-in mobile device management
• Pre-stage switches and/or configure and troubleshoot over the web
• If you need it, switches can be physically stacked via dedicated cabling, or better still use Meraki virtual stacking to manage ports anywhere.

Data^#3 can help

If your telco contract for your legacy WAN is about to expire, don’t renew it without first exploring a software-defined WAN alternative. With the deployment of the National Broadband Network (NBN) now making high speed internet services available to most locations it is a logical time to consider how software-defined networking can enable you to take full advantage of your new network firepower.

But don’t slip into the complacency of thinking it’s all too high tech to worry about right now, or it’s not worth the hassle of switching contracts. There is also a compelling financial imperative that will make your bean counters sit up and take notice. Consider how much you’re spending on a traditional MPLS service and how much bandwidth you receive per site.

With Meraki SD-WAN, you can achieve 400mbps for $400-500 per month; that will likely be a fraction of your MPLS costs. The numbers speak for themselves, and we can help you in the discovery and ROI calculations.

Contact a Data^#3 networking specialist to see a demonstration. We can even set up Meraki at your office, in a parallel environment, so you can get hands-on in the context of your own network.