6dd493ff_mod_proxy___Apache_HTTP_Server__Description
[Parameter] ping [Default] 0 [Description] 
Ping property tells webserver to send a CPING request on ajp13 connection before forwarding a request. The parameter is the delay in seconds to wait for the CPONG reply. This features has been added to avoid problem with hung and busy Tomcat's and require ajp13 ping/pong support which has been implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+. This will increase the network traffic during the normal operation which could be an issue, but it will lower the traffic in case some of the cluster nodes are down or busy. Currently this has an effect only for AJP. By adding a postfix of ms the delay can be also set in milliseconds.
mod_proxy - Apache HTTP Server
Description