Disclaimer: This repository is a git-svn mirror of the project found at http://java.net/projects/jsip whose original repository is developed collaboratively by the Advanced Networking Technologies Division at the National Institute of Standards and Technology (NIST) - an agency of the United States Department of Commerce and by a community of individual and enterprise contributors. TeleStax, Inc. will perform some productization work, new features experimentation branches, etc for its TelScale jSIP product that doesn't concern the community from the main repository hence this git repository.
https://tools.ietf.org/html/rfc5049