Overview

What is Load Balancing?

Load Balancing is used to distribute network traffic among available network paths. This distribution can be even between network paths or it can be weighted to take advantage of unbalanced bandwidth capabilities. The end result is improved performance for all network traffic coming in and out of an organization’s network fabric. An additional benefit is automatic failover in the event of a network link failure to any available links remaining.

How does Load Balancing Work?

Load balancing leverages traffic steering technology in order to balance traffic going in and out of an edge controller. Traffic steering is used when the router is configured with multiple internet connections or tunnels for reasons such as balancing outgoing LAN traffic, maintaining network redundancy and faults for one or multiple lines. The LAN traffic is distributed by using a weighted round-robin policy over the multiple internet gateways or tunnels. In other words it\’s connection based load balancing. Traffic can also be steered through a single interface. The detection of traffic is done by the flow classifier module, which offers multiple ways of detecting traffic like 5-tuple, nDPI, L7, etc..

Functionality

Load Balancing supports 2 modes of traffic:

1. Branch
2. Internet Breakout

In Branch mode, gateways can be grouped based on the LAN network to form a separate load balancing group In Internet breakout mode, any traffic which does not belong to the branches are forwarded to the default internet gateways

Each load balancing group can be configured in 2 modes

1. Load balancing and Failover
2. Failover

Failover monitoring is done by either monitoring the liveliness of the physical interface or the gateway IP address or manually configured Failover IPs to verify the absence of routing issues. The reliability of the latter can be influenced by the network level congestion and their response times. So proper calibration is required for the same. There are multiple parameters which are used to avoid transient failure detection like

1. Number of probes before marking DOWN
2. Number of probes before marking UP
3. Pause before New Cycle
4. Reply Timeout

Configuration Steps

Add a Load Balancer gateway

Edit a Load Balancer gateway

View the Load Balancer gateways

Configure the Load Balancer

Use Cases

To classify and steer traffic over dedicated links.

Known Limitations

• Only 99 Load balancer Gateways can be created per zWAN Edge Controller