RFC 864 (rfc864) - Page 1 of 3
Character Generator Protocol
Alternative Format: Original Text Document
Network Working Group J. Postel
Request for Comments: 864 ISI
May 1983
Character Generator Protocol
This RFC specifies a standard for the ARPA Internet community. Hosts on
the ARPA Internet that choose to implement a Character Generator
Protocol are expected to adopt and implement this standard.
A useful debugging and measurement tool is a character generator
service. A character generator service simply sends data without regard
to the input.
TCP Based Character Generator Service
One character generator service is defined as a connection based
application on TCP. A server listens for TCP connections on TCP port
19. Once a connection is established a stream of data is sent out
the connection (and any data received is thrown away). This
continues until the calling user terminates the connection.
It is fairly likely that users of this service will abruptly decide
that they have had enough and abort the TCP connection, instead of
carefully closing it. The service should be prepared for either the
carfull close or the rude abort.
The data flow over the connection is limited by the normal TCP flow
control mechanisms, so there is no concern about the service sending
data faster than the user can process it.
UDP Based Character Generator Service
Another character generator service is defined as a datagram based
application on UDP. A server listens for UDP datagrams on UDP port
19. When a datagram is received, an answering datagram is sent
containing a random number (between 0 and 512) of characters (the
data in the received datagram is ignored).
There is no history or state information associated with the UDP
version of this service, so there is no continuity of data from one
answering datagram to another.
The service only send one datagram in response to each received
datagram, so there is no concern about the service sending data
faster than the user can process it.
Postel
