UDP

NAME

UDP (User Datagram Protocol)

SPECIFICATION

J. Postel. User Datagram Protocol. Request for Comments 768, USC Information Sciences Institute, Marina del Ray, Calif., Aug. 1980.

SYNOPSIS

UDP is a trivial protocol that dispatches messages that arrive at the host to a process running on the host.

REALM

UDP is in the ASYNC realm.

PARTICIPANTS

UDP removes a pointer to a long (the UDP port number) from the participant stack. UDP ports must be less than 0x10000. If the local participant is missing, or if the local protocol number is ANY_PORT, UDP will select an unused local port.

CONTROL OPERATIONS

UDP_ENABLE_CHECKSUM:

Cause the session to use checksums on its outgoing packets. (session only)

Input:

none

Output:

none

UDP_DISABLE_CHECKSUM:

Cause the session to not use checksums on its outgoing packets. (session only)

Input:

none

Output:

none

UDP_GETFREEPORTNUM:

Returns an unused UDP port number. This port number will not be given out to subsequent UDP_GETFREEPORTNUM calls until it is released with UDP_RELEASEPORTNUM. This allows an opener to separate reservation of free ports from the actual open operation, if desired. (protocol only)

Input:

none

Output:

long

UDP_RELEASEPORTNUM:

Releases a UDP portnumber previously acquired with UDP_GETFREEPORTNUM. (protocol only)

Input:

long

Output:

none

CONFIGURATION

name=udp protocols=ip;

AUTHORS

Larry Peterson and Sean O'Malley