Network Redundancy vs. Network Diversity in Wide Area Networking

Network Diversity and Network Redundancy. Two different, if not complementary, concepts, which can be a little confusing. While both help to accomplish a common goal, they aren’t synonyms, as they are often portrayed. We’ve covered some of this in a previous post, but in this blog we’ll dig deeper into the differences, similarities, and contributions each makes to the Wide Area Network (WAN) environment.

Defining Network Redundancy and Network Diversity

Let’s start by breaking down the two concepts.

• Network Redundancy is the presence of duplicate elements within a network infrastructure. It ensures continued operation and reliability in the event of a failure or disruption.

• Network Diversity, on the other hand, involves the use of distinct and physically separate paths, technologies, or providers for network connections. This enhances its reliability and resilience against failures, including natural disasters or intentional attacks.

As you can see, both facilitate network continuation, but in different ways. If you’re curious about the business implications of continuity, you can discover them in the linked blog.

Key Considerations for Network Redundancy

If you’re planning redundancy failovers for a network, what matters most?

Hardware

When planning redundancy into a network topology, redundant hardware systems should be top of your list. The most redundant hardware systems are set up in High Availability (HA), ensuring automatic failover. Several equipment protocols have been established to assist with these HA topologies. Of note are Cisco’s Hot Standby Router Protocol (HSRP) and Virtual Router Redundancy Protocol (VRRP).  

The primary goal in HA topology is to enhance the fault tolerance of the WAN by eliminating a single point of failure for the routing devices. When two devices are set up in HA, if the primary device hardware fails, the secondary HA device will automatically become primary and take over. 

Other topologies are not automatic but do still offer redundancy protections, such as a cold standby, where the backup device is on-site but inactive until needed. Another option is a warm standby, where a backup device is partially online and can be inserted into the network faster.  

Topology

Several routing topologies also offer some form of redundancy. For dedicated internet services, for example, Border Gateway Protocol (BGP) routing allows for the rehoming of public IP addresses between different paths. Ring and star topologies also offer redundancy through multiple path options. You can also explore N-modular redundancies.

What Are the Pros and Cons of Network Redundancy?

Each layer of added redundancy lowers your exposure to network outages. The goal is to achieve network continuity, so the business-critical applications continue to run no matter what.

However, redundancy comes with a cost for the network assets and from the administration side. Extra routers and connectivity costs money, both as operational expenditure and capital expenditure. Each added layer needs to be maintained and adds administrative and maintenance burden on the business.

What Considerations Are There for Network Diversity?

Now you have a clearer picture of network redundancy, let’s look more closely at network diversity.

Physical Separation

It’s also possible to have a single network service provider install their services to your site using diverse paths. These paths can be physically separated into the building, such as where one enters via the north side and a second via the south side.  You can also diversify using physical path diversity with carrier diversity as well. That way if the carrier that is providing their services via the south side of the building has an issue, then the carrier that enters via the north side will take over.  

Diversity can also be created with completely different mediums altogether. The network might have services that enter the site via fiber, coax, hybrid fiber coax (HFC), LTE/5G, satellite, and even transport only (like WAVE).  Lightyear often encounters customers who require both high bandwidth and low latency. The best way to provide that is with fiber. But in scenarios where fiber will be the primary and secondary connection type, it’s extremely important to ensure there is physical separation in the fiber routes to avoid a single point of failure taking the system down entirely.

Topology

There are also common network topologies that will help to facilitate network diversity. Utilizing cloud or SaaS services in conjunction with on-premises services is a common scenario. Think of fully meshed networks, like SD-WAN, that can leverage the benefits of diverse carriers in addition to diverse routes. 

What Are the Pros and Cons of Network Diversity?

Diversity in network elements lowers exposure to a single point of failure. The more diverse the network is, the lower the odds of complete failure. However, like redundancy, there is a cost to finding ways to diversify. The costs in the diversification of network elements are typically slanted heavily toward research and deployment costs. In many cases, spending time doing due diligence to ensure separation is the most taxing part of the setup. To get this right, you’ll need to request .KMZ files from carriers to validate routes and do a bit of desktop network engineering before purchasing circuits. 

If validating route diversity or planning for network redundancy doesn’t sound fun to you, the Lightyear Telecom Operating System can help. The platform’s network intelligence can do a lot of the desktop homework for you, and we have a time that will request and validate .KMZ route diversity on your behalf based on specifications you determine, so reach out today!