diff --git a/hbc b/hbc
index cb30a60..abe2b4d 100755
--- a/hbc
+++ b/hbc
@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python
 # $Id: hbc,v 1.9 2012/03/29 02:08:36 andreas Exp $
 # NEW
 import sys
@@ -11,7 +11,7 @@ import string
 import select
 import errno
 import traceback
-import md5
+from hashlib import md5
 import shutil
 import zlib
 import subprocess
@@ -35,7 +35,7 @@ def log(msg):
 	if fdaemon:
 		syslog.syslog(syslog.LOG_ERR, msg)
 	else:
-		print msg
+		print(msg)
 
 def handler(signum, frame):
 	if signum == signal.SIGTERM:
@@ -82,7 +82,7 @@ class Conn:
 		msg['id'] = self.conId
 		msg['ver'] = VER
 		msg['time'] = time.time()
-		m = dicttos(ID, msg, True)			# always compress
+		m = dicttos(ID, msg)			# always compress
 		if verbose:
 			log("conn.send('%s', (%s:%s) %s)" % (msg, self.addr, self.port, len(m)))
 		try:
@@ -93,14 +93,20 @@ class Conn:
 			self.close()
 			return
 		self.send += 1
-		self.lastsend = time.time()
+		self.lastsend = msg['time']
+		print("RTT self.lastsend %s" % self.lastsend)
 
 
-	def ack(self, msgDict):
-		self.lastack = time.time()
-		self.lastacksent = float(msgDict.get('time','0'))
-		if verbose: log("ack RTT: %0.1f ms" % ((self.lastack - self.lastsend) * 1000.0))
-		self.rtts.append((self.lastack - self.lastsend) * 1000.0)
+	def ack(self, msgDict, now):
+		try:
+			self.lastack = msgDict['time'] 
+			mul = 2
+		except:
+			self.lastack = now
+			mul = 1
+		rtt = (self.lastack - self.lastsend) * mul
+		if verbose: log("ack RTT: %0.1f ms (now %s)" % (rtt * 1000.0, now))
+		self.rtts.append(rtt * 1000.0)
 		if len(self.rtts) > 10:
 			del self.rtts[0]
 		self.ackcount += 1
@@ -113,11 +119,11 @@ class Conn:
 
 
 def shortname(name):
-	r = string.split(name, '.')
+	r = name.split('.')
 	return r[0]
 
 
-def dicttos(ID, d, compress=False):
+def dicttos(ID, d):
 	s = []
 	for k in d:
 		if type(d[k]) == type(1.2):
@@ -125,15 +131,35 @@ def dicttos(ID, d, compress=False):
 		else:
 			s.append("%s=%s" % (k, d[k]))
 	pk = ";".join(s)
-	if compress:
-		zpk = zlib.compress(pk, 6)
-		ID = "!"+ID
-	else:
-		zpk = pk
-	return ID + ":" + zpk
-
+	zpk = zlib.compress(pk.encode(), 6)
+	ID = "!" + ID + ":"
+	return ID.encode() + zpk
 
 def stodict(msg):
+	d = {}
+	if len(msg) > 0 and chr(msg[0]) == "!":
+		pk = zlib.decompress(msg[5:]).decode()
+		d['ID'] = msg[1:4].decode()
+	else:
+		r0 = msg.split(':',1)
+		pk = r0[1]
+		d['ID'] = r0[0]
+	r = pk.split(';')
+	for v in r:
+		vr = v.split('=', 1)
+		k = vr[0].strip()
+		if len(vr) == 1:
+			d[k] = None
+		else:
+			v = vr[1].strip()
+			if v[0].isdigit():
+				v = eval(v)
+			d[k] = v
+	print("DBG: msg is %s" % d)
+	return d
+
+
+def XXstodict(msg):
 	d = {}
 	r0 = msg.split(':',1)
 	if len(r0) == 1:
@@ -167,7 +193,7 @@ def syslogtrace(note):
 	for l in logm.split('\n'):
 		syslog.syslog(syslog.LOG_ERR, ' tb: %s' % l)
 	if verbose:
-		print logm
+		print(logm)
  
 
 conId = 1
@@ -188,13 +214,13 @@ def createConnections(hosts):
 			elif r[0] == 2:
 				af=socket.AF_INET
 			else:
-				print "dont know this net type: %s" % r[0][0]
+				print("dont know this net type: %s" % r[0][0])
 				sys.exit(1)
 	
 			addr = r[4][0]
 			conns[conId] = Conn(conId, addr, hb_port, af)
 			if verbose: 
-				print "cons[%s] = %s" % (conId, str(conns[conId]))
+				print("cons[%s] = %s" % (conId, str(conns[conId])))
 			conId += 1
 
 
@@ -258,14 +284,14 @@ def doupdateone(code, csum):
 
 def restart():
 	if verbose: 
-		print "restart: execv %s %s" % (sys.argv[0], [sys.argv[0]]+cmdargs)
+		print("restart: execv %s %s" % (sys.argv[0], [sys.argv[0]]+cmdargs))
 	syslog.syslog(syslog.LOG_ERR, 'restart %s' % (sys.argv[0]))
 	e = "fallthrough" 
 	try:
 		os.execv(sys.argv[0], [sys.argv[0]]+cmdargs)
 	except Exception as e:
 		pass
-	print "should not be here:", str(e)
+	print("should not be here:", str(e))
 	log('restart failed: %s' % e)
 
 
@@ -287,7 +313,8 @@ def process():
 			if sleep <= 0:
 				break
 			try:
-				r=select.select(ifiles.keys(),[],[],sleep)
+				r=select.select(list(ifiles.keys()),[],[],sleep)
+				now = time.time()	# nb: delay from actual packet arrival to select is ca. 105ms!
 			except KeyboardInterrupt:
 				running = False
 				break
@@ -304,16 +331,16 @@ def process():
 			for rfh in r[0]:
 				conn = conIds[rfh]
 				data, addr = ifiles[rfh].recvfrom(MAXRECV)
-				if verbose: print "sock.recvfrom: %s (%s) %s" % (addr, len(data), data[:4])
+#				if verbose: print("sock.recvfrom: %s (%s) %s" % (addr, len(data), data[:4]))
 				msgDict = stodict(data)
-				if verbose: print "sock.recvfrom: %s (%s) %s" % (addr, len(data), str(msgDict)[:80])
+				if verbose: print("sock.recvfrom: %s (%s) %s" % (addr, len(data), str(msgDict)[:80]))
 				if msgDict == None:
-					 print "bad backet from %s (%s) %s" % (addr, len(data), data)
+					 print("bad backet from %s (%s) %s" % (addr, len(data), data))
 				elif msgDict['ID'] == "ACK":
-					conns[conn].ack(msgDict)
+					conns[conn].ack(msgDict, now)
 				elif msgDict['ID'] == "UPD":
 					if doupdate(conn, msgDict) == None:
-						if verbose: print "process: restart after update"
+						if verbose: print("process: restart after update")
 						dorestart = True
 						break
 				elif msgDict['ID'] == "CMD":
@@ -369,7 +396,7 @@ def daemonize(working_dir="/", stdin='/dev/zero', stdout='/dev/null', stderr='/d
 		if pid > 0:
 			# exit from first parent
 			os._exit(0)
-	except OSError, e:
+	except OSError as e:
 		sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
 		os._exit(1)
 
@@ -383,7 +410,7 @@ def daemonize(working_dir="/", stdin='/dev/zero', stdout='/dev/null', stderr='/d
 		if pid > 0:
 			# exit from second parent
 			os._exit(0)
-	except OSError, e:
+	except OSError as e:
 		sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
 		sys.exit(1)
 
@@ -438,20 +465,20 @@ for o,a in optlist:
 
 
 cmdargs += args
-if verbose: print "cmdargs for restart are %s" % cmdargs
+if verbose: print("cmdargs for restart are %s" % cmdargs)
 
 if helpflag:
-	print "hbc HeartBeatClient"
-	print "usage: hbc [-bdhv] [-c configfile] [-m msg][host1 [..]]"
-	print
-	print "	-b	indicate machine boot"
-	print "	-c configfile"
-	print "	-d daemonize"
-	print "	-h this help"
-	print "	-m send a message"
-	print "	-v verbose"
-	print
-	print """ config file can contain 
+	print("hbc HeartBeatClient")
+	print("usage: hbc [-bdhv] [-c configfile] [-m msg][host1 [..]]")
+	print()
+	print("	-b	indicate machine boot")
+	print("	-c configfile")
+	print("	-d daemonize")
+	print("	-h this help")
+	print("	-m send a message")
+	print("	-v verbose")
+	print()
+	print(""" config file can contain 
 hb_hosts=('host1', 'host2', ..._
 hb_port=50003
 interval=20
@@ -459,7 +486,7 @@ logfile=...
 logfmt={|test|msg}
 grace=SECONDS
 reportstrict={True|False}
-"""
+""")
 
 	sys.exit(1)
 
@@ -473,9 +500,9 @@ iam=socket.gethostname()
 
 try:
 	f=open(configfile,"r")
-	if verbose: print "notice: using config file %s" % configfile
+	if verbose: print("notice: using config file %s" % configfile)
 except:
-	if verbose: print "warning: running without config file: %s" % configfile
+	if verbose: print("warning: running without config file: %s" % configfile)
 	f=None
 
 if f:
@@ -487,14 +514,14 @@ if f:
 		if r[0] == 'hb_hosts':
 			hb_hosts=eval(r[1])
 			if verbose:
-				print "notice: cfg hb_hosts: %s" % hb_hosts
+				print("notice: cfg hb_hosts: %s" % hb_hosts)
 		elif r[0] == 'interval':
 			interval=eval(r[1])
 		elif r[0] == 'hb_port':
 			hb_port=eval(r[1])
 		elif r[0] == 'name':
 			iam=eval(r[1])
-			if verbose: print "name set to %s" % iam
+			if verbose: print("name set to %s" % iam)
 	f.close()
 
 if len(args) != 0:
@@ -502,17 +529,17 @@ if len(args) != 0:
 	
 
 if len(hb_hosts) == 0:
-	print "no hb server specified"
+	print("no hb server specified")
 	sys.exit(1)
 
 # 
 if verbose:
-	print "notice: hb_hosts: %s" % str(hb_hosts)
-	print "notice: hb_port: %s" % hb_port
-	print "notice: interval: %s" % interval
-	print "notice: iam: %s" % iam
-	print "notice: msgonly: %s" % msgonly
-	print "notice: msgboot: %s" % msgboot
+	print("notice: hb_hosts: %s" % str(hb_hosts))
+	print("notice: hb_port: %s" % hb_port)
+	print("notice: interval: %s" % interval)
+	print("notice: iam: %s" % iam)
+	print("notice: msgonly: %s" % msgonly)
+	print("notice: msgboot: %s" % msgboot)
 
 if not msgonly:
 	msgboot['interval'] = interval
@@ -531,20 +558,20 @@ if verbose:
 	log("%s connections created" % (len(conns)))
 
 if len(msgboot) > 0:
-	if verbose: print "on boot"
+	if verbose: print("on boot")
 	msgboot['acks'] = 0 
 	for conn in conns:
 		conns[conn].sendto(msgboot)
 
 if msgonly:
-	if verbose: print "msgboot done msgonly=%s" % msgonly
+	if verbose: print("msgboot done msgonly=%s" % msgonly)
 	closeall()
 	sys.exit(0)
 
 # 
 syslog.openlog('hbc', syslog.LOG_PID, syslog.LOG_DAEMON)
 if fdaemon:
-	print "daemoinizing."
+	print("daemoinizing.")
 	daemonize()
 	daemonized = True
 	syslog.syslog(syslog.LOG_ERR, 'starting heartbeat to %s' % ','.join(hb_hosts))
@@ -555,7 +582,7 @@ try:
 	process()
 except:
 	syslogtrace('process')
-	if verbose: print "err: process exit: %s" % e
+	if verbose: print("err: process exit: %s" % e)
 
 if verbose: log( "main: cleanup")
 cleanup()