Target Skill:

List the BillerXpert components and identify the function of each  

NAS Load Balancing

A NAS server cluster provides load balancing, which is required for a scalable EBPP system. In a NAS cluster, processing load is distributed efficiently among many web servers, application servers, and information sources. With its distributed synchronization facility, a NAS cluster also eliminates a single point of failure and supports the EBPP requirement for reliable, fault-tolerant operation.  The following illustration shows how NAS load balancing works with a cluster containing 3 servers.
 

  1. The web server relays a request to NAS1 
  2. NAS1 determines that NAS3 is the most available and sends a message informing the web server.
  3. The web server updates its NAS load table and sends the request to NAS3
  4. NAS3 performs the required process, interfacing to datasource or external information sources, as necessary, and returns the result directly to the web server. 
  5. Future requests from the web server go directly to NAS3 based on priorities & server load. 
The NAS Distributed Synchronization Facility provides the infrastructure for distributed applications and enables distributed state/session management across servers. State information can be accessed symmetrically from all servers. This eliminates a single-point of failure and helps guarantee reliable access to data stores and other information sources. 
 

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