2018-02-17 15:48:52 +11:00
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# Minitel - Layer 5
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2018-02-17 15:46:08 +11:00
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## Language
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- Node: a device on a minitel network
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- Client: node establishing a connection
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- Server: node accepting a connection
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## Establishing a connection
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- Client sends "openstream" to the server on the port it would like to connect to
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- Server can refuse, and respond with anything but a number
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- Server, upon accepting, sends a string representation of another port, chosen by the server, on the same port, to the client
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- Server sends a random string of its chosing to the client, which will be used to close the session
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- Client and server can now exchange messages
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## Ending a connection
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- Upon either side deciding to close, it sends the previously generated random string
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- Neither side should send packets now
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## Example exchange:
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Acknowledgements are implied.
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Client bob sends request to open a connection on port 40:
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`"packet ID 1", 1, "alice", "bob", 40, "openstream"`
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Server alice accepts and sends a port to client bob for further communications:
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`"packet ID 3", 1, "bob", "alice", 40, "32800"`
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Server alice then sends a string on that port as a close session marker:
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`"packet ID 4", 1, "bob", "alice", 32800, "asdfghjkl"`
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Nodes alice and bob can now freely exchange data on that port:
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`"packet ID 5", 1, "alice", "bob", 32800, "random data and stuff"`
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`"packet ID 6", 1, "bob", "alice", 32800, "response data"`
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Client bob decides to close the connection, and sends the close session marker:
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`"packet ID 7", 1, "alice", "bob", 32800, "asdfghjkl"`
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