Initial Connection Protocol - Reviewed (RFC0197)
Original Publication Date: 1971-Jul-14
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
A. Shoshani: AUTHOR [+2]
Network Working Group A.Shoshani, SDC
Request for Comment # 197 E. Harslem, Rand
NIC # 7142 14 July 1971
Categories: C.3, D.1
INITIAL CONNECTION PROTOCOL--REVIEWED
At the Network meeting preceding the SJCC '71, an
"ICP Committee" was established. It's purpose was to get
"something" working fast with minimum modifications to the
current ICP so as to minimize complaints. (This seems like
a good definition for almost everything!) Consequently,
those who had objections to the current ICP were interviewed
and a compromise was reached in the form of RFC #165. The
ICP committee didn't have a chance to think about an alter-
native because of the above mentioned constraints. In this
note we attempted a simple version of an ICP assuming that
we can add commands to Host-Host protocol. We hope that this
will be useful in the design of the next version of the
To establish a regular connection one party can issue
an INIT (NCP sends RTS or STR commands), then the other
party can accept the request for connection by responding
with an INIT or refusing it with a CLOSE. We think that
a similar, simple mechanism is desirable for the ICP.
Furthermore, the ICP should allow for simplex as well as
duplex connections from user to server.
The following commands are necessary for simplex
ISC - Initiate Simplex Connection
ASC - Accept Simplex Connection
RSC - Refuse Simplex Connection
The notation for parameters is similar to that
of RFC #165:
L - Server socket name, in one special case the
server is "logger".
U - User socket.
S - Socket assigned by server for the connection
X - Is the byte size if U is odd and is the link
number if U is even.
X - Is the complement of X (X is the link number
if U is odd and byte size if U is even.
To initiate a simplex connection the user's NCP
ISC, L, U, X
To refuse this connection the server's NCP issues:
RSC, L, U
To accept this connection the server's NCP issues:
ASC, L, U, S, X
Similarly, for duplex connections, we have:
IDC, L, U1, X1, U2, X2
RDC, L, U1, U2
ADC, L, U1, S1, X1, U2, S2, X2
where (U1,U2), (S1,S2), (U1,S1) and (U2,S2) are pairs of
After the server accepts the connection(s), it (they)
goes immediately to a "connected state", and the appropriate
ALL command(s) must be sent.
The main advantage to this approach is that it mini-
mizes the dialog between user and server. The server socket
L is used only as an address, not a socket to connect to,
therefore eliminating the need to establish a connection to
L, choose a byte size, send an ALL comm...