End-to-end connectivity

End-to-end connectivity is a property of the Internet that allows all nodes of the network to send packets to all other nodes of the network, without requiring intermediate network elements to further interpret them.

Recently many network elements and technologies that limit this property of Internet Protocol have become fashionable such as network address translation, requiring network elements to support each individual protocol that is used on top of it. This hinders deployment of new applications that use the Internet in ways other than opening Transmission Control Protocol connections to other Internet hosts. Examples of hurt applications and protocols include IPsec, migration to IPv6 (tunneling IPv6 in IPv4), Peer-to-peer applications, and networked games. There are practical reasons for limiting this property, first the IP address space is a limited resource and it is common to have fewer real IP address than one requires, the other is security, as using some kind of address translation also limits the routing scope, which means that computers behind NAT cannot be addressed directly from untrusted zones.

Increasingly 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.

= External links =

*[http://www.alcatel.com/publications/abstract.jhtmlrepositoryItem=tcm%3A172-288441635 End-to-End Ethernet Connectivity Fault Management in Metro and Access Networks] Technology White Paper *[http://www.cybertelecom.org/notes/end_to_end.htm End to End]