You decided to boost your office WAN links, both in terms of Internet speed, as well as reliability, so you are looking into WAN load balancing and WAN bonding appliances as a solution. You have various services running on your network, some are based on internal servers that are on premises, some are on your private cloud and some of your services are powered by public cloud servers. One question you want to clarify is the IP addressing scheme for your network once you implement the WAN load balancing. How will the WAN load balancer at your branch offices handle the IP addresses on your various ISP connections and how will this affect your services?
To address this question, we will look at two different types of WAN load balancers: the legacy WAN load balancers that spread Internet traffic with session granularity (i.e. session-level link load balancers) and the modern WAN load balancers that implement true bonding (packet-level load balancing).
When you have a WAN load balancer with bonding capability, the field unit bonding routers will create a bonded overlay tunnel through a proxy node. The proxy node can either be at the corporate HQ/Data Center or hosted by a 3rd party in the cloud. This proxy node is particularly powerful. Beyond the enablement of bonding, it also facilitates the use of “Elastic Static IP” addresses. In essence, any of the static IP addresses in the HQ/Data-center can be mapped onto the branch office WAN load balancer. So any traffic that goes in or out from the branch office can use those static IP addresses at the proxy. This is particularly powerful since the reliability of the proxy (which is usually a high 9s data-center) is now transferred onto the branch offices, since the static IP addresses will be usable as long as at least one of the WAN connections on the branch office side is up. So the branch office can use various WAN links and still have the elastic static IP addresses available for use.
This of course translates into 100% service uptime for the branch offices, even for their services that rely on static IP, as long as at least one (doesn’t matter which one) of their WAN links is functioning.
This setup is also valuable in situations where static IPs may not be available at the branch office locations at all (because of ISP limitations, cost restrictions, etc.). By making use of the overlay bonding tunnel between the branch office WAN load balancer and the proxy unit in the cloud, the branch offices can be enabled with these elastic static IPs.
Coming back to legacy WAN load balancers without true bonding capabilities, the elastic static IP functionality will not be available. In this case, you will have to use the available static IPs on the ISP WAN links. If that link goes down, you are out of luck in terms of services that depend on that IP address.
If elastic static IP is a must-have for keeping your services fault tolerant against ISP failures, then the modern WAN load balancers with true WAN bonding capabilities are the way to go.
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.