This page provides a starting point for finding information about SIP applications, which are Java programs that use at least one Session Initiation Protocol (SIP) servlet written to the JSR 116 specification.
SIP is used to establish, modify, and terminate multimedia IP sessions including IP telephony, presence, and instant messaging.
This page describes preliminary SIP servlet tuning for Linux 2.6 kernel.
You might want to implement one or more of the following tuning suggestions if you are encountering performance issues while running SIP servlets.