WAN modernization evolves in tandem with advancements in computing architectures and the devices that access them
There’s a good chance that the concept of a wide-area network (WAN) has been around longer than you. Its inception is largely traced back to the late 1950s, when the U.S. Air Force created a network of phone lines and modems for the Semi-Automatic Ground Environment radar defense system (SAGE).
Although SAGE was rudimentary compared to today’s enterprise network architecture, most of us have experienced an even simpler version of a WAN using cups and string in the childhood game of telephone. Imagine all that your 6-year-old self could have accomplished if that cup was connected to not just one cup, but multiple clusters of cups, spaced thousands of miles apart. Throughout the years, engineers have used that same imaginative thinking to improve and refine WAN technology to complement advancements in computer architecture and devices.
To visualize the history of wired and Wireless WAN for enterprise networking, explore our history of WAN infographic.
WAN modernization throughout the decades
Each decade marks a unique and dramatic shift in WAN modernization. Here are the highlights since 1980.
The 1980s: centralized mainframe computing
The ’80s marked the beginning of enterprise networks, with virtually every network in the world running on leased, multi-point wirelines. These lines sent data from predominantly IBM mainframes to front-end processors, and finally to computer terminals, at speeds typically around 9.6 Kbps.
Jim Metzler, Ph.D., is the founder and vice president of Ashton, Metzler & Associates. With an extensive background in systems software, mathematical modeling of computer networks, and the development of telco network services, he describes the essential building blocks of mainframe computing architecture during this time as:
- The end user devices in branch offices
- The network connecting those branch office devices
- The WAN connecting the branch offices to a datacenter
- A mainframe computer and front-end processors
Cradlepoint Chief Marketing Officer Todd Krautkremer, an IBM network engineer in the 1980s, recalls the tedious processes associated with early mainframe computing.
“Communication was an extension of mainframe computing — the two were inextricably linked,” he said. “Customer interactions with applications on the mainframe were done on a dumb terminal. Every time you hit a key, information went back and forth to the mainframe on a channel at speeds around 9.6 Kbps.”
As manufacturing methods and materials evolved, PCs became more affordable and dumb terminals were ultimately put out to pasture. Enterprise businesses outfitted their offices with IBM PCs and even some Apples, leading to the next advancement in enterprise WAN architecture: distributed computing.
The 1990s: distributed computing
Most office PCs during this era were used by accountants or those in finance and insurance industries whose jobs relied heavily on data input. Soon those users needed their PCs to talk to printers and clusters of other PCs, thus giving birth to the local-area network (LAN).
“PCs became the most important way in which you connected people to applications,” Krautkremer said. “Ultimately, the shift to PCs was met by a shift in computing. Instead of having highly centralized mainframes, people began to move their computing out of the mainframe and to more distributed, mid-range systems from DEC and IBM that were more optimized for communicating with PCs.”
The shift to distributed computing grew in tandem with TCP/IP. This new connect-all protocol for both LANs and the WAN also gave rise to frame relay networks, which allowed for more efficient WAN communication. Frame relay services were multiprotocol in nature, helping with network transitions from IBM to proprietary LANs and TCP/IP, and were significantly cheaper to operate, which left businesses clamoring to set them up. According to Metzler, the frame relay adoption rate beat out the public Internet as the fastest uptake of any WAN service in history.
The 2000s: virtualized, server-centric computing
As businesses adopted an increasingly global mindset, server farms replaced mainframes and distributed mid-range computers, and applications became more centralized while virtual private networks (VPN) and multiprotocol label switching (MPLS) also began to take center stage. MPLS, the successor to frame relay, was more TCP/IP-native and offered a way to prioritize traffic and create more efficient routing of data on lease-lined circuits.
“Intelligent networks during this time recognized that customers had different types of traffic coming from their business sites that required different types of priorities,” Krautkremer said. “MPLS allowed network engineers to have different quality of service across the WAN, allowing for more seamless end-to-end connectivity of applications and remote LANs. Now, instead of frame relay, the network became a differentiated, carrier-provided service.”
From there, it was a very short step to the rise of SD-WAN.
2010s: Centralized cloud computing
The tech scene during this era was booming, to say the least. The 2010s saw the launch of the iPad, Instagram, Microsoft Azure, and the first activation of 4G LTE in the U.S. As networks, devices, and applications became increasingly mobile and bandwidth usage exploded, MPLS and traditional data centers began their long decline, which is still happening today
Replaced by intelligent, reliable, and secure cloud-based technologies, enterprise businesses found increased value in moving their operations closer to the edge using LTE and SD-WAN to help get them there. SD-WAN controls network traffic to ensure a certain outcome based on customer-defined protocols.
Reflecting on this WAN modernization, Rohit Mehra, vice president of Network Infrastructure at the International Data Corporation (IDC), said this: “Enterprise WAN is being rapidly re-architected to cost-effectively deliver new, secure, cloud-centric capabilities. Understanding and adapting to current WAN network and security solutions across the emerging connectivity and application landscape is going to be a key ingredient for success.”
Participants in a 2021 study/report from IDC agreed, indicating one of their top reasons for embracing SD-WAN is to “simplify management of WAN to support hybrid IT/multicloud.”
“SD-WAN is the last epoch of the wired networking world for fixed sites, but enterprise businesses today have moved beyond exclusively fixed sites,” Krautkremer said. “They have vehicles, IoT devices, and kiosks, and connecting all of these critical business assets, anywhere, is what takes us into the current decade.”
The 2020s: Hybrid cloud computing and Wireless WAN
Today, the low latency and high bandwidth benefits provided by 4G LTE and 5G solutions have enabled wireless connections to become essential infrastructure of WANs. Wireless WAN (WWAN) provides the agility and reach that modern WANs need to deliver rapid deployment; support high-availability cloud access; and connect people, places, and things anywhere — all with much fewer humans than ever before.
“Enterprise business today requires constant connection to people, places, and things anywhere,” Krautkremer said. “Over time, as 5G demonstrates that it can deliver ‘fiber fast and cellular simple connections,’ customers will deploy 5G as a MPLS alternative.”
Not only is WWAN becoming more universal, but IDC forecasts the Private LTE/5G market to reach $5.7 billion in 2024 as security, mission-critical accessibility, scalability, and centralized management continue to be top considerations for enterprise business networking solutions.
“With more spectrum being made available for enterprise uses, coinciding with the arrival of commercial 5G, interest has grown toward using private LTE/5G solutions as a basis for connectivity across a multitude of mission-critical, industrial and traditional enterprise organizations,” said Patrick Filkins, senior research analyst, IoT and Mobile Network Infrastructure, at IDC.
WAN modernization: a continuous evolution
Wide-area network: the three little words that connect our world. From modest beginnings to an intricate, global web, WAN will continue to evolve alongside computing, device, connectivity, and business needs.
“Every shift in networking has happened because of a change in computing architectures and the type of devices connecting to them,” Krautkremer said. “Both of these transitions happen in parallel, and the network always follows: from mainframe computing, to distributed computing, to client server computing, to SD-WAN, and now to hybrid cloud and edge computing. We’re continuing to move beyond fixed sites and connecting devices of people, places, and things.”