Health check filters

The most common traffic steering filters include the health check filters, which consider availability-related metadata when processing incoming requests.

Table 1. Health check filters
Filter	Description	Related metadata
Up filter	This filter eliminates "down" or unavailable endpoints from the list based on the up/down metadata for each answer. Typically, this filter is used as part of an automatic failover configuration where the up/down status for each answer is automatically updated by a connected data feed. This configuration ensures incoming requests to your application endpoints and services are directed to available endpoints.	Up/down
Shed Load filter	This filter rearranges the list of answers or eliminates answers from the list depending on a load-related metric and user-defined low and high watermark values. The filter references one of three load-related metadata fields in each answer: load average, active connections, or active requests. If the observed load reaches the low watermark, the filter begins to prioritize alternative endpoints (answers) at an increasing and proportional rate as the load approaches the high watermark. If the load measurement reaches the high watermark, the filter eliminates the answer altogether. Typically, this filter is applied as part of an automatic load-shedding configuration, which helps prevent your application users from being directed to overloaded endpoints.	Load average Active connections Active requests High watermark Low watermark