My Server and Client run both on Linux.<br>
The Server broadcasts multicast, the Client listens multicast.

My Client has to migrate to another site,<br>
and unfortunately multicast is not allowed between the two sites :-(

**How to convey multicast between the two sites?**<br>
Through TCP or UDP?<br>
What about latency?

----------

**Current:** Server and Client on the same site

    ----------    ------------
    | Server |    |  Client  |
    | sends  |    | listens  |
    |multicst|    | multicast|
    |  IP1   |    |   IP2    |
    ----------    ------------
        |              |      
        |     LAN      |      
        ----------------      
             |                WAN              
             ---------------------------....

**Future:** Server and Client, each one on a different site

    ----------    ------------      ------------
    | Server |    |          |      |new host  |
    |        |    |          |      |for Client|
    |   IP1  |    |          |      |   IP3    |
    ----------    ------------      ------------
        |              |                 |  
        | LAN of site1 |                 |  LAN of site2
        ----------------                 ----------...
             |                WAN              |
             -----------------------------------


I use the multicast channel: 224.1.0.1:6666

I received an answer about router configuration (GRE),<br>
but I am afraid one of the network teams may be reluctant<br>
because the transmission should not be broken during the working day<br>
and I suppose changing a router or just changing its configuration may break the transmission<br>
Is there other solutions? for instance based on _Linux kernel features_?