Operating instructions
M300USERSGUIDE SEA
GENERALINFORMATION
43
These protocol used port number (aka sockets) or port names that are defined in the /etc/services
files.
TCP is one to one, reliable protocol, slower, harder to setup.
UDP is one to many, un-reliable protocol, faster, easy to setup.
For the most part UDP does a great job. The packet loss is minimal the way we typically setup our
systems. Only one system can send UDP data on network ports (aka sockets). Many systems are able
to listen to this data.
QNXSETUPFORM300UDPOPERATIONS
UDP is the TCP/IP User-Datagram Protocol. It is a connection less protocol requiring very little
overhead. The following QNX setup must be done prior to using the M300 for broadcasting UDP
data. Note that all machines planning to use UDP for the M300 need to have the following
configuration.
1. Modify the ‘/etc/services’ file to include the following at the bottom, just below the “QNX
Services” entries.
#
# SEA
#
sea-udp 2001/udp
radar-udp 2000/udp
2. Next, modify the ‘/etc/netstart’ file to include the following line that is in bold.
export SOCK=$NODE
/bin/slay -f Tcpip;
/bin/prefix -D /dev/console >/dev/null 2>&1;
/bin/prefix -A /dev/console=/dev/con1;
/usr/ucb/Tcpip qnx &
/usr/ucb/ifconfig en1 192.9.200.2 up
/usr/ucb/ifconfig lo0 localhost up
/usr/ucb/ifconfig en1 broadcast 192.9.200.255
#usr/ucb/route add 224.0.0.0 192.9.200.2
#usr/ucb/route add 225.0.0.0 192.9.200.2
/usr/ucb/route add default 192.9.200.40
#/usr/bin/syslogd
# Note: to act as an NFS server, uncomment the next line
# /etc/nfsstart
# Note: to act as a TCP/IP server, uncomment the next line
/usr/ucb/inetd &