The Internet Engineering Task Force (IETF) protocol (RFC 5996) that is used to set up a security association in the Internet Protocol Security (IPsec) protocol suite.
Source(s):
NIST SP 800-57 Part 2 Rev.1
A protocol used to negotiate, create, and manage its own (IKE) and IPsec security associations.
Source(s):
NIST SP 800-77 Rev. 1