A rendezvous protocol is a computer network protocol that enables resources or p2p network peers to find each other. Examples of rendezvous protocols include Sun Microsystems' JXTA, SIP, Freenet Project, I2P, and such protocols generally involve NAT hole punching. Because of firewall network address translation issues, rendezvous protocols generally require that there be at least one unblocked and un-NATed servers that lets the peers locate each other and initiate concurrent packets at each other.