The traditional corporate WAN architecture is one that everyone working in IT will be familiar with. This kind of network became popular in the client/server architecture era, and the WAN architectures were built largely to support branch-to-datacentre communication.
On paper, these often-looked like cloud architectures, but they are in effect hub and spoke networks, with the hub being the data centre.
This set up worked well, as long as most applications were hosted in one or two datacentres, and access to the Internet was centralised and only available through the datacentre firewall. However, with the increasing use of cloud, this architecture has become costly and inherently inefficient in terms of compromising application performance, business agility, and employee productivity. Most significantly, the WAN is becoming a blocker to digital transformation, rather than an enabler.
The rising demand for cloud connectivity and Internet access at the branch is driving the need for a new architecture – a need that SD-WAN is attempting to meet. So, what is it?
SD-WAN decouples the application paths from the underlying network transport. Doing this provides an ability to run any application over any transport or combination of transports. This could be MPLS, the Internet, mobile or even satellite networks. This ability allows SD-WAN to connect branch offices and remote sites in a different way to the traditional hub and spoke model. It does this typically by creating a Hybrid WAN - one that includes at least two WAN connections from each branch office and leverages two or more different networks (e.g. MPLS, broadband internet, 3G/4G, etc) and where all branch WAN connections are active.
The SD-WAN centralised policy controller develops an application-aware overlay network based on the underlying transport networks. This enables the SD-WAN to provide application-driven intelligent path selection across the WAN links based on policies centrally defined on the controller. For example, VoIP through the QoS enabled MPLS network while Office 365 and Facebook across the broadband Internet connection. This allows the SD-WAN to balance loads across the WAN connections, or to monitor application performance and send traffic over the lowest cost or the most reliable WAN links, depending on application requirements.
Cloud-based applications can route directly to and from cloud services and branch locations, instead of through the traditional route of a centralised Internet connection. SD-WAN ensures that branch offices and remote sites are configured consistently to connect users to applications while assuring security compliance and optimising network and application performance, reducing complexity and costs in the process.
Hybrid WAN is where the network has more than one WAN service provisioned at a branch office or site – typically this uses MPLS and broadband Internet, however it can be a mix of any WAN technology e.g. MPLS, Internet, LTE, satellite, etc. Historically, using multiple different WAN technologies was both technically challenging and difficult to manage and therefore most often a secondary connection was only used as back up for a failed primary connection – often at a limited number of sites requiring high availability. SD-WAN solves these challenges by making management and provision simple, with ‘zero touch deployment’ and offers the benefit of using all available connections simultaneously ensuring higher availability and cost efficiencies.
The SD-WAN solution can improve network and application availability and performance, especially in relation to cloud applications and services, while providing cost-effective bandwidth at the branch.
But the real benefits are in providing cost-effective delivery of business applications, as well as cloud-based applications and services through automated service provisioning. This will result in greater enterprise productivity and business agility. It is this business agility that will enable digital transformation. Being agile is now key to business growth - this agility has enabled many enterprises to disrupt their industries and quickly gain market share.
Traditional WANs are unable to provide the level of agility required to drive the improved performance and speed of change businesses now demand. SD-WAN solutions are beginning to meet these challenges, creating better, more agile solutions that can adapt quickly to meet our growing need for faster change and cloud delivered applications.
According to Gartner, by the end of 2023 more than 90% of WAN edge infrastructure refresh initiatives will be based on virtualized customer premises equipment (vCPE) platforms or software-defined WAN (SD-WAN) software/appliances. With this in mind, here are 6 considerations for the CTO before adopting SD-WAN:
How will current and future security policy be implemented in the SD WAN environment? SD -WAN architectures may include multiple Internet ingress points to the organisation which may need changes to the security design.
FarrPoint consultants are active in this area advising clients in their strategy, design and implementation of SD-WAN technology, and are available to help answer these questions and more.
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