The Tomcat property, maxThreads, specifies the maximum number of simultaneous requests that can be handled by the HTTP Connector. For more details, refer to the Tomcat documentation at http://tomcat.apache.org/tomcat-7.0-doc/config/http.html
The following is the HTTP Connector section, from ../tomcat/config.xml, created by default when a Proxy Agent instance is created.
<Connector port="8981" maxHttpHeaderSize="8192"
maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" redirectPort="5698" acceptCount="100"
connectionTimeout="20000" disableUploadTimeout="true" />