{TAIL ~ The network} includes a long haul portion with multicast enabled routers and {HEAD ~ non multicast} enabled routers 
{ TAIL ~ The network } includes a long haul portion with multicast enabled routers and { HEAD ~ non multicast } enabled routers
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH