NCP, the Network Control Program, was the predecessor of TCP/IP. [1]
Host addresses were only 8 bits (zero was reserved), so there could only be up to 255 hosts on the ARPANET.
NCP was a simplex protocol, not full duplex like TCP/IP, so each port=>port connection transmitted data in only one direction, and applications would use an even/odd pair of ports for two-way communication.
The parity of the ports at each end of the connection was required to be different: you couldn't connect an even port to another even port, or an odd port to another odd port. "Homosocketuality" was strictly forbidden by internet protocols! NCP's mandatory "heterosocketuality" was called the "Anita Bryant feature". [2]
> The parity of the ports at each end of the connection was required to be different: you couldn't connect an even port to another even port, or an odd port to another odd port. "Homosocketuality" was strictly forbidden by internet protocols! NCP's mandatory "heterosocketuality" was called the "Anita Bryant feature". [2]
> ...
> [2] https://news.ycombinator.com/item?id=12422813
Well, that's a whole distasteful part of computer history I was blissfully unaware of before now. As someone fairly young (in my early 20s), it's sometimes hard to remember that things like this are very recent history, so I guess it helps to have some perspective every now and then.
Host addresses were only 8 bits (zero was reserved), so there could only be up to 255 hosts on the ARPANET.
NCP was a simplex protocol, not full duplex like TCP/IP, so each port=>port connection transmitted data in only one direction, and applications would use an even/odd pair of ports for two-way communication.
The parity of the ports at each end of the connection was required to be different: you couldn't connect an even port to another even port, or an odd port to another odd port. "Homosocketuality" was strictly forbidden by internet protocols! NCP's mandatory "heterosocketuality" was called the "Anita Bryant feature". [2]
[1] https://en.wikipedia.org/wiki/Network_Control_Program
[2] https://news.ycombinator.com/item?id=12422813