1. Load Balancer:
   1. A load balancer spreads out the network load to various switches, routers, and servers.
2. Cluster:
   1. A set of nodes that work together so closely that they may functionally be considered the same system
   2. Active-Active
      1. An active-active cluster is typically made up of at least two nodes, both actively running the same kind of service simultaneously.
      2. The main purpose of an active-active cluster is to achieve load balancing.
      3. Load balancing distributes workloads across all nodes in order to prevent any single node from getting overloaded.
      4. Because there are more nodes available to serve, there will also be a marked improvement in throughput and response times.
      5. Within an active-active cluster, all nodes participate in load-balancing simultaneously.
      6. The load balancer distributes traffic across all devices according to a configured schedule.
      7. Active-active load balancing is much more efficient than active-passive, but requires intimate systems design knowledge.
   3. Active-Passive
      1. Within an active-passive cluster, a single node acts as the active node, and bears all traffic forwarding responsibilities.
      2. All other configured nodes within the cluster act as failover devices.
3. Virtual IPs
   1. Load-Balancing Protocols and Redundancy Protocols configure device groups using Virtual IP addresses, shared between device group members.
4. Scheduling
   1. Affinity
      1. The allocation, or scheduling, of computing tasks on the computing nodes where they will be executed more efficiently.
      2. Also called priority queuing or weighted queuing
   2. Round-Robin
      1. Units of time are assigned to each process in equal portions and in circular order, handling all processes without priority.
      2. Round-robin scheduling is simple, easy to implement, and starvation-free.