Lantronix Discovery Protocol

This example is a Python application in source code that shows how to search and find Lantronix Devices. It is run from the command line.
The Lantronix Discovery protocol uses a UDP broadcast out port 77FE on a network interface. All Lantronix devices on that subnet will respond with 30 bytes of data.
Their MAC address is included in the 30 bytes

Prerequisites

1) import socket, time and sys
2) While this code could be incorporated and run from a PremierWave device, it was written and tested on a PC. (win 7)

Sample Code

# utility to search and find Lantronix devices
#

import socket   #for sockets
import sys  	#for exit
import time

j = 0
k = 0
host = ''
port = 30718
DATA = []
LTRXnode = []
packet = []
 
print "searching for Lantronix devices...\n"
 
# create datagram udp socket
try:
	s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
	s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
	s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
	s.bind((host,port))
	s.settimeout(2)
except socket.error:
	print 'Failed to create socket'
	sys.exit()
 

#Set the search string
msg = chr(0)+chr(0)+chr(0)+chr(0xf6)

try:
	s.sendto(msg, ('<broadcast>', port))
except socket.error, msg:
	print 'Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
	sys.exit()
#time.sleep(4)
t1 = 0
t0 = time.clock()										# set start time
	
while (t1<3):											# loop for no more than 3 seconds
	try:
		# receive data from client (data, addr)
		d, address = s.recvfrom(128)
		packet = "".join("%02x" % ord(c) for c in d)
		if packet[6:8] == "f7":
			LTRXnode.append(address[0])
			DATA.append(packet[48:60])
			j += 1
	except Exception:
		#print "no rcv"
		s.close()
	
	time.sleep(1)
	t1 = time.clock() - t0								# find difference in time
	#print t1	

# print out results of search
print "%d devices found " % j
	
for x in LTRXnode:
	print "%s  %s " % (x,DATA[k])
	k +=1

print "\n"
		
raw_input('Press the Enter Key to Exit\n')