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Local Load Balancing

Load balancing is a method for evenly distributing processing or service requests across devices in a network.  At AppNexus we use "load balancing" primarily to mean local load balancing within a datacenter, rather than global load balancing between datacenters.

With local load balancing, identical instances are clustered into a pool and a load balancer distributes traffic among the instances, or nodes, in the pool.  It is most commonly used either to enlarge capacity or for redundancy.

Equipment

Each AppNexus datacenter uses a redundant pair of F5 BIG-IP 6400 Local Traffic Managers (LTMs) for local load balancing.  The LTMs are in constant communication with each other; if the primary fails, the secondary will immediately take over.

A Few Additional Features of Our Load Balancing Pools:

  • It's easy to create and manage load balancing pools using our API command-line tools.  You also have the flexibility to write your own tools that can interact directly with our API.
  • We support session persistence; this means that session-specific information is collected and stored on a specific server, and a client is automatically directed to that same server on subsequent visits.
  • We support SSL for secure communication.

Set up

At AppNexus you can set up and manage local load balancing through our API with the command-line tools manage-lb-ip and manage-lb-pool.  See Configuring Local Load Balancing for more information.

Next core concept: Global Load Balancing