diff --git a/examples/test/test_intfoptions.py b/examples/test/test_intfoptions.py
index abd5d01..6f1ebec 100755
--- a/examples/test/test_intfoptions.py
+++ b/examples/test/test_intfoptions.py
@@ -13,27 +13,29 @@ class testIntfOptions( unittest.TestCase ):
     def testIntfOptions( self ):
         "verify that intf.config is correctly limiting traffic"
         p = pexpect.spawn( 'python -m mininet.examples.intfoptions ' )
-        tolerance = .8
+        tolerance = .2  # plus or minus 20%
         opts = [ "Results: \['([\d\.]+) .bits/sec",
                  "Results: \['10M', '([\d\.]+) .bits/sec",
-                 "h(\d+)->h(\d+): (\d)/(\d), rtt min/avg/max/mdev ([\d\.]+)/([\d\.]+)/([\d\.]+)/([\d\.]+) ms",
+                 "h(\d+)->h(\d+): (\d)/(\d),"
+                 "rtt min/avg/max/mdev ([\d\.]+)/([\d\.]+)/([\d\.]+)/([\d\.]+) ms",
                  pexpect.EOF ]
         while True:
             index = p.expect( opts, timeout=600 )
             if index == 0:
+                BW = 5
                 bw = float( p.match.group( 1 ) )
-                self.assertGreaterEqual( bw, float( 5 * tolerance ) )
-                self.assertLessEqual( bw, float( 5 + 5 * ( 1 - tolerance ) ) )
+                self.assertGreaterEqual( bw, BW * ( 1 - tolerance ) )
+                self.assertLessEqual( bw, BW * ( 1 + tolerance ) )
             elif index == 1:
                 BW = 10
                 measuredBw = float( p.match.group( 1 ) )
                 loss = ( measuredBw / BW ) * 100
-                self.assertGreaterEqual( loss, 50 * tolerance )
-                self.assertLessEqual( loss,  50 + 50 * ( 1 - tolerance ) )
+                self.assertGreaterEqual( loss, 50 * ( 1 - tolerance ) )
+                self.assertLessEqual( loss,  50 * ( 1 + tolerance ) )
             elif index == 2:
                 delay = float( p.match.group( 6 ) )
-                self.assertGreaterEqual( delay, 15 * tolerance )
-                self.assertLessEqual( delay,  15 + 15 * ( 1 - tolerance ) )
+                self.assertGreaterEqual( delay, 15 * ( 1 - tolerance ) )
+                self.assertLessEqual( delay,  15 * ( 1 + tolerance ) )
             else:
                 break