Why Every Enterprise WAN Is Unique

by Sorell Slaymaker

The future looks very bright for network architects.  Every enterprise Wide Area Network (WAN) is unique and this will continue, even as networking technology moves to software.  It is estimated that Cisco and its resellers get over $50 Billion in professional services revenue every year due to the customization and complexity of every enterprise network.

Through software defined networks, better orchestration tools, and market innovation, enterprise WANs will hopefully get simpler, but unlike compute and storage, each enterprise WAN will always be unique.  The following is a list of attributes that influence the architecture of every enterprise WAN.

  1. Geographical Footprint – The location of offices, partners, manufacturing, … Some businesses are concentrated in a small geographical area such as a hospital system that may have 8 hospitals and 90 clinics in one county.  Others are distributed all around the world.  Local bandwidth is cheap resulting in an enterprise network that tends to overbuild their network versus global bandwidth which is expensive and has high latency, resulting in WANs that are tightly managed and will utilize WAN optimization technologies.
  2. Business Vertical – Enterprises with lots of small branch offices such as banks, insurance, or commodity retail versus those with a few large sites such as manufacturing, pharmaceutical, higher education. Some enterprises are a mix of both.  Small branch offices utilize traditional copper based access (T1/E1, DSL, Cable) while large sites have optical access and the cost per Mbps is 1/100th of the cost.  Those organizations with a few large sites typically deploy a layer 1/2 WAN utilizing technologies such as VPLS while the enterprise with thousands of small sites utilize layer 3 technologies such as MPLS or Internet VPN to scale.
  3. Business Applications – Some businesses are very transaction oriented, so their network bandwidth needs are simple. Other businesses are very interaction oriented and require video collaboration and sharing of very large CAD, MRI, or other large files, which consumes 100x the bandwidth.  The location of the applications, in the cloud, private data center, or within the office impacts the network design.
  4. Security Policies – The security position of being minimally compliant, or industry standard, or best in class has a direct correlation on the network security requirements. Network access control, encrypting all data in motion, network parameter strategy (a few Internet exit points and trust the internal network versus zero trust networking) impact the amount of network routing and efficiency of the network.  Too many networks backhaul traffic when going from the enterprise network to the public Internet.  Also, different industries have regulatory requirements that influence the security required, such as credit card transactions running on their own segmented network.
  5. Lifecycle Management – Every enterprise has contracts with network service providers along with network technology vendors and replace each in different 6-8 year timeframes. Each major refresh and change is a significant investment in time and money, and with each major change, utilizing the technologies and products available at the time.  A major network refresh takes 3-4 years and then an organization wants to harvest the investment for 3-4 years.
  6. Organization Dynamics – The decision makers and priorities of the decision makers are different. Some businesses centralize all IT infrastructure into one team to try and get economies of scale, while others have IT controlled by each major business division.  With centralized IT, some businesses charge back directly to each business division, while others use a shared pool business model.  Different decision makers value cost, reliability, and performance differently which shapes the overall network architecture.
  7. Culture – IT architecture philosophy including:
    1. Best of breed versus single vendor
    2. A defined architecture versus project by project planning
    3. Treating the WAN as a utility versus business differentiating
    4. Insource vs. outsource some or all network functions and/or management

There are surely other factors that also contribute to making every enterprise WAN architecture unique.  Networks are complex, and it is incumbent on every good network architect to keep things as simple as possible while also not trying to follow any preset design.  IoT, Cloud, Mobile, and digital business are sure to keep network architects busy for the foreseeable future.