| Horizontal Scalability |
added more application machines, very fast and reliable solution offering high availability, load balancing, and proxying for TCP and HTTP-based applications |
| supporting tens of thousands of connections is clearly realistic with todays hardware |
| Round-Robin Algorithm |
distributed load to backend application server according to their weights |
| Least-Conn Algorithm |
distributed load to backend application server according to theirlowest number of connections, recommended where very long sessions are expected, such as SQL query |
| Source Algorithm |
ensures that the same client IP address will always reach the same server as long as no server goes down or up |
| URI Algorithm |
ensures that a same URI will always be directed to the same server as long as no server goes up or down |
| URL-Parameter Algorithm |
track user identifiers in requests and ensure that a same user ID will always be sent to the same server as long as no server goes up or down |
| HTTP-Header Algorithm |
HTTP header name which specify will be looked up in each HTTP request and request will always be sent to the same server as long as no server goes up or down |
| RDP-Cookie Algorithm |
useful as a persistence mode, always send the same user or the same session ID to the same server |
| High Availability |
high availability load balancer itself, if primary fail the backup will promote immediately |
