Added quality of service(QOS) via Differentiated services (#330)

* Added quality of service(QOS) via Differentiated services

* Altered to classify network traffic in Ingress

* Updated readme for QoS

exercises/qos/receive.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+
+import sys
+from scapy.all import sniff, get_if_list
+
+
+def handle_pkt(pkt):
+    print "got a packet"
+    pkt.show2()
+    sys.stdout.flush()
+
+
+def main():
+    iface = 'eth0'
+    print "sniffing on %s" % iface
+    sys.stdout.flush()
+    sniff(iface=iface, prn=lambda x: handle_pkt(x))
+
+
+if __name__ == '__main__':
+    main()