Today\u2019s enterprise relies heavily on applications for just about every business function, making it critical for administrators to have full visibility into networks to better manage traffic and application usage. With MPLS (multiprotocol label switching) networks, this level of visibility is virtually impossible because those networks weren\u2019t designed with an application-first mentality, but that is changing with the implementation of software-defined networks (SDN).\nOften, administrators don\u2019t even know what apps are on their network or they know only what traffic comes in and out of their firewall\/proxy servers. SDN, which replaces most network hardware with software-based controls, is providing transparency that administrators never had before, allowing them to steer application traffic to achieve the best performance.\nMPLS limitations\nMPLS networks were built in a narrowband era before the web, social media and hosted applications changed the nature of traffic. MPLS emphasized quality of service and interconnectivity more than visibility and control.\nToday 79 percent of workloads are in the cloud, according to RightScale. Whereas network managers previously were tasked simply with creating the best environment for hub-and-spoke voice, video and data, today\u2019s networks need to be reimagined with applications top-of-mind.\nBeyond the traffic, legacy MPLS networks provide limited insight into bandwidth consumption. As a result, if the network gets creaky and slow at certain times of day, it\u2019s hard to pinpoint what\u2019s causing it. Perhaps too many employees in one location are using YouTube or other streaming sites at lunchtime. The site may be using a T1\/1.5-megabit circuit, which can\u2019t handle the increased traffic and brings the connection to a screeching halt.\nWithout enough bandwidth to support modern application demands, business networks can slow to a crawl. And because administrators often cannot pinpoint the cause of the problem without visibility, they struggle to deliver exceptional user experiences.\nWhen MPLS networks were originally built, traffic patterns were different. All data would travel through a centralized hub \u2013 often a data center. With the proliferation of branch offices and the migration of workloads to cloud infrastructures, it doesn\u2019t make sense to send everything through the hub anymore, but rather to establish direct connections between the different locations.\nThat\u2019s where SDN \u2013 and the advent of modern high-speed gigabit broadband connections come together to create a \u201cgenerational moment\u201d in data networking.\nOptimized for apps\nSDN and software-defined wide area networks (SD-WAN) are optimized to handle applications, as opposed to bits and bytes. They are more scalable, which makes it easier to support bandwidth-heavy applications \u2013 and manage the network itself.\nCentralized management provides administrators the visibility they need to make changes in real time with the click of the mouse instead of having to reconfigure sites manually. These changes can make a big difference in how wide area networks perform.\nFor example, a dental office wants to offer public guest Wi-Fi to patients in the waiting room. If the service uses the same traffic flows as the VPN (virtual private network) that transmits customer records, a bottleneck is bound to occur if enough patients take advantage of the Wi-Fi simultaneously. Without SDN, it would be difficult to identify the source of the problem and fix it. SDN makes it easier to avoid the problem in the first place, because an administrator can identify the source of the traffic and take the necessary action to correct it and deliver the desired experience for both customers and the back-office.\nTrying to pinpoint bandwidth-hogging activity with MPLS requires a variety of time-consuming tools \u2013 and multiple screens to look across the network to view various policies. SDN changes all that, with the ability to deliver robust, network-wide reporting on application consumption as well as and visibility for administrators at the application layer. Today\u2019s SDN platforms allow for administrators to achieve a holistic view across their enterprise network via a single screen using a mobile or desktop application to understand what\u2019s happening down to the port or device level across business locations.\nAn administrator can determine if the use of an application is personal or business-related, figure out whether mobile devices are in use, and pinpoint the specific applications, web and mobile sites users are accessing. This is a big leap from legacy systems that make it hard to even know what applications are in the system, including unauthorized apps that could create security issues in addition to increased bandwidth demands.\nEnterprise agility\nToday\u2019s applications demand stability and reliability, something that is difficult to achieve without the transparency administrators need to identify trouble spots. SD-WAN can detect and measure latency, packet loss and jitter and easily adjust network policies to keep the network performing in peak condition. This, in turn, adds the flexibility and agility that enterprises will need to compete into the future.\nSDN is an emerging technology that promises to deliver unprecedented insight and control for administrators. As a result, enterprises will be able to place applications at the center of all network-related decisions, from planning and design to ongoing management to future planning.