What structure should I use for multi to multi connection(tcp) through server

[alex.]

It need to make a program on server run as attached picture. May I know what kind of structure should use on server.

Every device can only have one tcp link.

Every link has 2 ports, one for command, one for data.

[Brandyn]

How many connections will you have? Ideally you will need something that scales very nicely.

[Mark_Yedinak]

Are your clients and devices independent of each other. Can client 1 talk to both device 1 and device 2? Is the server acting as a broker between the clients and the devices? Your picture implies this is the case. Also, your picture implies that the devices act as clients also. That is, they are required to initiate the connection with the server.