In my company the guys propose some solution to the customer which I’m not sure that it is the right one.
The scenario:
I have 4 units A,B,C,D.
Unit A sends unicast to unit B with src 10.1.1.1 and destination 10.2.2.2
Unit A sends multicast with src 10.1.1.1 and destination 225.1.1.1
Unit B sends multicasts 224.10.10.10 and 225.2.1.1
Unit C sends unicast to unit D with src 10.3.3.3 and destination 10.4.4.4
Unit C sends multicast with src 10.3.3.3 and destination 225.1.1.2
Unit D sends multicasts 224.20.10.10 and 225.2.1.1
Unit A is connected with unit B, Unit C is connected to unit D
(the most important one) unit A shall be able to send unicasts to unit D with src 10.1.1.1 and destination 10.4.4.4 and unit C shall be able to send unicasts to unit D with src 10.3.3.3 and destination 10.2.2.2. A,C are connected only to one of the units at a defined time
(the scenario is simplified, but there are more such units like A,C and B,D
All those units are over WAN and as the WAN blocks the multicast, there is a need to have GRE tunnel. Now, if there would be static tunnels, there could be couple of problems:
One of themn is a packet duplication – if A is listen to multicasts sent from B, but D is also sends the same multicast (225.2.1.1), there could be a duplicate (which is forbidden).
How to overcome this problem (except that there would be a dynamic GRE tunnel between each of the pairs (A,B), (C,D), (A,D), (C,B) which will be created on demand)?
