Load Balancing Algorithms and Limitations
Link load balancing refers to dual-WAN or multi-WAN routers that can accept more than one WAN connection. A load balancer (or load balancing firewall) will then distribute the outbound links that are generated from the LAN and are destined for the Internet.
There are various types of load balancing algorithms that can be implemented for distributing the load between the available WANs, such as round robin load balancing, weighted round robin load balancing and many others. Unlike true bonding dual-WAN routers, load balancing is blind to the size of the sessions that it is processing. In other words, the load balancer has no means to determine if the session it is assigning to one of the WAN links will be a short-lived, small session or a large session with heavy traffic. Because of this incomplete information, load balancers are very limited in terms of intelligently utilizing the WAN links and in some scenarios (such as 3G/4G LTE load balancing) can even provide worse performance than a single WAN link.
True broadband bonding WAN routers work quite differently. Since these bonding firewalls have the ability to split the traffic at a more granular level (at packet level or smaller), they can more efficiently aggregate traffic between the WAN links. True bonding algorithms are capable of bonding various types of WAN links (DSL, cable, 4G/LTE, T1, MPLS, satellite) with close to 100% efficiency.
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.