Load Balancing

Availability is crucial to handling Internet traffic. Slow responses or refused connections create dissatisfied users. Load Balancer has superior high availability, scalability, AND load balancing.

The first generation of Web traffic load balancing, called round-robin DNS, had a domain name server (DNS) rotating traffic among a hard-coded list of IP addresses for Web application servers. This balancing is hardly optimal, since the DNS round-robin treats all the requests as equal, and does not take into account the availability of the servers, or their workload on them. DNS also does not provide the ability to differentiate by port.

Load Balancer is the next generation of server load-balancing software. It can direct TCP/IP session requests to different servers belonging to a group of servers, and automatically find the optimal server to handle the request. Load Balancer also offers content-based routing, where requests are routed to specific servers depending on the content of the URL request. For HTTP traffic, this is accomplished by using Caching proxy.

Rules-based Balancing

Rules-based balancing uses rules, and a set of servers among which to load balance, if the rule is obeyed. You can use this to fine-tune when and why packets are sent to which servers. Load Balancer reviews any rules you add from first priority to last priority, stopping on the first rule that it finds to be true, then load balancing the content between any servers associated with the rule. Load Balancer provides the following types of rules:

  • client IP address
  • client port
  • time of day
  • total connections per second for a port
  • active connections for a port
  • reserved bandwidth
  • shared bandwidth
  • content
  • metric specific rules: metric all and metric avg
  • always true
  • content of a request
  • content of Type of Service (TOS) in IP header

Balancing maximizes your hardware resources. Load Balancer provides a powerful, flexible, and scalable solution to peak-demand problems with Web servers.


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