Multiple Sessions per Host

Most of the text on DSR might suggest that the producers or consumers of data services were communicating with just one other computer at a time. Internet packets include port numbers from the sender and receiver which distinguish among several contexts in the recipient host.

The DSR analog is presumably for a host DSR adapter to allocate enough internal turn ops to distinguish among internal agents authorized to launch datagrams, to be included in the initial outgoing DSR packet as it crosses its first real link. A format A packet would have an initial non-empty return path as it entered the network. In the format B version the turn op cursor would already point a few turn ops into the path information for a brand new packet. In either case the normal path reversal logic would return reply packets not only to the correct host but to the correct agent therein. In short the path incorporates both the IP address and port number of Internet.

This pattern works for both ends of a datagram packet route, and also circuits. This pattern obscures the nature of the edge of the network but to no ill effect that I can see.

Extending the path notion into a host raises the question of the rôle of the scout and guide. The host, with more function than a network switching node, is in a position to inform scouts that it is the ultimate destination and holder of the private key corresponding to the presented public key. This still allows that host to reply to queries with packets that include return paths with additional turn ops in its replies, rather like the “Reply To:” field in e-mail.

Of course the host can play the rôle of yet more switching layers in case it serves parties of diverse interest each of which do their own style of communications security.