SDx: software-defined everything comes to the LAN

Enterprise campus network architectures have been fairly constant in design terms for many years, with often only the number of ports and users affecting their layout. Today, new challenges are appearing. End-user expectations have changed beyond recognition, making mobility and security priorities vital across an increased number and diversity of devices. How can software-defined networking (SDN) power next-generation LANs to ease network management headaches?

Virtualization is happening across all layers of the networking stack. SD-WANs and SDDCs (software-defined data centers) have rapidly become a key priority for the majority of enterprises. Meanwhile, the software-defined LAN and wireless LAN (SD-LAN and SD-WLAN) are about to take center stage as part of this software-defined everything (SDx) trend.

The goal is to enable campus LANs, wireless networks and WANs to become part of a single infrastructure, centralizing network control to meet end-user demand, speed up cloud application performance and ease management tasks. A single, intuitive network lets businesses cut complexity and share intelligence across the network, implement security policies, troubleshoot problems and configure changes all at once.

More and more devices now connect to campus LANs, including smartphones, tablets, wearables and other IoT devices. According to Analysys Mason, fixed IP data traffic grew at 43 percent in 2017 and will continue to grow at a factor of 3.9 from now until 2023. The majority of workers has now been migrated to laptops and will no longer tolerate wireless dead spots as they move around a building to collaborate with colleagues. In addition, many cloud applications that employees use require high network speeds, and poor performing WLAN and LAN infrastructure may not be up to the job.

“More of everything on the network has brought management to the front of people’s thinking, and the best way forward is to push policies to campus networks in systematic, automated ways,” says Thomas Sourdon, Senior Manager at Orange Consulting, Orange Business.

New technologies in the LAN, WAN and data center

With that in mind, what technology trends can we expect to see impact campus networks in the near future?

Software-defined networking (SDN)

SDN emerged from the data center to make a significant impact in the WAN, and now it is making its presence felt in the LAN. From a management perspective, the LAN is very different from the WAN, since, in the WAN, IT teams only really see and interact with edge devices, such as routers. In the LAN, they must manage every device, including switches, core switches and so on.

For campus networks, SD-LAN makes operational management and troubleshooting easier thanks to a more straightforward configuration – a traditional pain point. It does this by creating an application- and policy-driven architecture that unchains hardware and software layers while creating self-organizing and centrally-managed networks that are simpler to operate, integrate and scale.


This is a big driver for virtualized LANs as it enables campus IT managers to separate users based on their profiles, which can include their roles or the business units in which they work. This enables them to set different security rules for different types of users across the campus with much greater levels of overall control. Doing this in a traditional LAN can be complicated and hard to manage.

Wireless only

Also known as wireless-only connectivity, this is addressing the different nature of today’s end-users – they are mobile. Campus networks no longer want copper cables or fixed line connectivity to serve users, they want 100 percent wireless connectivity across the entire environment.

WLAN technology is evolving fast to provide more bandwidth (>1Gbit/s) and support an increased device density and wider range of services. For example, the new Wi-Fi 6 and Wi-Fi 7 standards (802.11ax and 802.11ay) are expected to be adopted in 2019.

Softphones and desktop collaboration suites and the adoption of laptops rather than fixed desktop computers as a de facto standard are removing the dependency on cable infrastructure.

Ethernet is also entering a new area with the N-BaseT standard, which connects more powerful wireless access points, delivering over 1Gbit/s (2.5G or 5Gbit/s) on traditional copper cable with Power over Ethernet.

According to Sourdon, “Network technologies invented 30 years ago are simply no longer sufficient to provide the flexible campus networks that end users demand today. A new type of network infrastructure is required – one that offers consistent management, contextual insights and intelligent segmentation.”
“Trends like bring your own device (BYOD) and the Internet of Things (IoT) have affected campus environments, making networks more complex and complicated to manage. Users expect full wireless connectivity that lets them use their smartphones and other devices everywhere and enables unified communications and collaboration tools (UC&C) for doing work tasks.”

Passive Optical LAN (POL)

POL could potentially have a role to play in campus networks with its ability to scale up to very fast connectivity of as much as 10Gbps. Passive optical splitters use a many-fibers-to-one-fiber design, similar to Fiber to the Home (FttH), and can provide up to 64,000 ports from one switch. Further benefits are that it is more secure and reliable than Ethernet, simplifies cabling architecture and needs much less equipment, space and power. The caveat is that it is only realistic in new buildings, so it must be considered at an early stage of building design.

Leaf-spine networks

Further to SDN, LANs are undergoing another structural change with leaf-spine networks replacing traditional three-tier networks. Leaf-spine configurations have only two layers – the leaf layer and the spine layer – and offer benefits like all connections being utilized at once while still remaining stable and avoiding loops within the network.

Spine-leaf configurations are useful for data center LAN networks because there are huge volumes of east-west traffic, the transfer of data packets from server to server within a data center, and scalability needs. In a campus network, traffic is not local to the campus, but extends to the data center or Internet/cloud. The campus network will tend to use either a hierarchical multi-layer model, managed by SD-LAN technology which enables multi-pathing, or a central switch design which is also used in a Passive Optical LAN.


The next-generation mobile connectivity is not yet fully operational, but hopes and expectations are big, and it could play a wireless LAN role in campus networks. It has been talked about as the network for the IoT, and its ability to carry huge amounts of data could serve campus network users as well as remote users logging on to educational platforms.

In addition to 5G, the sixth-generation Wi-Fi 6 will be launched around the same time as 5G and will offer higher data rates, increased capacity, improved performance in dense environments and also improved power efficiency. So for increasingly connected office spaces and campus networks with multiple clients per user, or IoT with connected devices of every description, Wi-Fi 6 should be well-suited to handling those demands.

Transforming next-generation campus networks

The primary function of enterprise campus networks has not changed, but the technologies have.

“Campus networks must, first and foremost, give users access to applications, but they must now do it wherever users want access and connectivity,” says Sourdon. “And that must be underpinned by security, availability and network services.”

SDN and the evolution of the LAN will be central to that.

Read about our Managed LAN service for more information on the evolution of the LAN.