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This Building Block Type belongs to Working Area Network (NW). A Load Balancing facility (intelligently) distributes data traffic from one or more sources (clients) over multiple targets (central computing resources). In this way, the availability and scalability of a resource (e.g. an application) can be improved. The resources for which Load Balancing can be used include web platforms, application platforms, name resolution facilities, and so forth.
Some Load Balancing facilities can select an available target only when the client is initiating the connection; others can also reroute active connections from a target to another target. The latter often als needs support within the target implementation itself (e.g. HTTP session database). Furthermore, application of Load Balancing might require modifications to the client-target communications (e.g. setting or changing web session cookies) to achieve the load balancing goals.
Criteria for selecting a target system when setting up a new connection or redirecting an established connection may include:
- standard redistribution of load, based on availability of processing power and/or availability of the target system itself;
- at will of an operator, e.g. to relieve a target from operations for maintenance purposes (this is sometimes referred to as "Drain mode");
- based on data in the connection itself, e.g. the content of a network data packet (URLs, kiosk ID's, cookies).
The icon below can be used to represent this infrastructure function in graphical Pattern representations that it might be part of:
Variants of this Building Block Type
The following variants of this function have been defined:
No Pattern Variants based on this Pattern Type (yet)
Pattern Types using this Building Block Type
The following Pattern Types use this function:
|Pattern Variant||Brief Description||Owner||Maturity|
|PAT.Access Distribution||Access Distribution||J.A.H. Schoonderbeek||3|
|PAT.Data Zone Protection||Data Zone Protection||J.A.H. Schoonderbeek||3|