Software Defined WAN gave the industry the ability to create overlay tunnels living on top of physical WAN resources such as MPLS, ADSL, Cable, T1, fiber etc. A VNF load balancer is one such overlay that has the ability to load balance the traffic over the WAN links. Since the VNF load balancer is in essence software that can be deployed onto an SD-WAN appliance, it has the power of taking advantage of various types of intelligence and adaptability to optimize the WAN performance.
Load Balancing Granularity: Blind session based load balancing is the old way of aggregating 2 or more WAN lines. These type of legacy approaches have been static, non-reactive and blind, which translates into lower performance and no instantaneous failover. Modern VNF load balancers have the ability to manage the traffic load balancing at packet-level granularity, which means the overlay Virtual Network Function (VNF) can take action midway during a live session, and therefore can implement algorithms that will result in significant performance and reliability boosts.
An example would be a file transfer, which would have failed in case the WAN line carrying that session had a problem. However, with a modern VNF load balancer, since all the WAN links are available even for that single session, the same network problem would have been completely shielded from the application. In this example, it would have meant the file transfer would have continued, as the VNF load balancer routes around network problems in real-time. So, requiring packet-level load balancing in your VNF load balancer should be on the top of your list in terms of what to look for.
In-depth Telemetry: SD-WAN installations can take advantage of network architectures where a Relay Node (a cloud or data-center node that relays the traffic coming from the field appliance) is connected to the CPE units in the branch offices. This means there is higher control and therefore more visibility into the path that connects the CPE units to the Relays for all available paths. A good VNF load balancer should leverage the metrics monitored on the WAN paths to optimize the load balancing algorithms, but also should present a medium (portal) for the end user (the IT manager in this case) to monitor the metrics. The in-depth telemetry capabilities are fundamental for a modern VNF load balancer.
Intelligent and flexible SD-WAN algorithms: One of the other key components of a VNF load balancer is its ability to take advantage of the software defined nature of the overlay. This allows load balancer to be agile and proactive in dealing with performance and reliability related algorithms. Make sure to learn about how the VNF tunnels are working and what type of logic and flexibility they offer.
As a fourth and final item, I will group together important features that the VNF load balancer should check mark. These features are scalability, ease of configuration and management, and needless to say, a solid solutions reputation in the market.
Cahit Akin, CEO, Mushroom Networks, Inc.
Mushroom Networks is the provider of SD-WAN (Software Defined WAN) and NFV solutions capable of Broadband Bonding that enables self-healing WAN networks that route around network problems such as latency, jitter and packet loss.