The transmission control protocol/Internet protocol (TCP/IP) has this property.
However, many network elements and technologies do not have this property, such as network address translation. Without this property, each new protocol requires the specific support of network elements it travels through. This hinders deployment of new applications that use the Internet in ways other than opening TCP connections to other Internet hosts. Examples of hindered applications and protocols include IPsec, migration to IPv6 (tunneling IPv6 in IPv4), peer-to-peer applications, and networked games.
Sometimes end-to-end connectivity is deliberately broken for practical reasons:
This trend divides Internet users into those who have "real" Internet connectivity and those who are restricted to use applications that only use outbound TCP connections.
WIPO ASSIGNS PATENT TO ZTE FOR "METHOD FOR REALIZING END-TO-END CALL, END-TO-END CALL TERMINAL AND SYSTEM" (CHINESE INVENTOR)
Apr 14, 2011; GENEVA, April 14 -- Publication No. WO/2011/038637 was published on April 07. Title of the invention: "METHOD FOR REALIZING...
Thales and Voltage Security Forge Technology Integration and Partnership to Deliver End-to-End Encryption and Key Management to Secure Payments.(Company overview)
Feb 02, 2010; Thales, leader in information systems and communications security, and Voltage Security, Inc., the global leader in...