NWG/RFC 49 Conversations with Steve Crocker (UCLA) first method is an undesirable implementation within the network (while the second is impossible). I put forth several reasons why (and I think Steve agreed). (a) The link over which the quit character is to be transmitted may be blocked. (b) While the interrupt is most effectively implemented within the NCP, it is undesirable for the NCP to place any particular structure on the data being transmitted. (See discussion below.) This would be required if the NCP were to scan a data stream for a control character. (c) Scanning the input stream greatly reduces NCP efficiency in a subsystem where speed is critical to effective operation. Steve pointed out that the implementation of INT as a "quit" should not necessarily preclude a HOST's interpretation of a control character in the input stream from also acting as a "quit". 3) Steve is opposed both to including the instance tag in the socket identifier and reserving a null field in the identifier for future definition. He cited several reasons: (a) Multiple processes of a single user should be indistinguishable to a foreign process. (I agree with this in certain cases when processes are co-ordinated in joint action. But what about the case where two processes of the same user both want to independently use the network?) (b) A process wishing to connect to one of a foreign user's processes does not know the instance tag of the particular process that he wants, and he can't easily find out. (c) If an instance tag should later prove desirable it could be added with some difficulty. (I claim that something as fundamental as the length of a socket identifier will prove very resistant to change.) Tom stated that perhaps the low order three bits of the user code could be reserved for later interpretation as an instance tag. He doesn't think that a separate field is of great importance. Steve's arguments seem to have merit. Perhaps Tom's suggestion is the way to go. I am currently undecided on this matter. 4) We all (Steve and MAC) seem to agree that at the NCP level there should be no special structure imposed on the data transmitted. To an NCP all data to be transmitted are bit strings of arbitrary length. One