SATEL technical bulletin
Using TCP over the radio can be secure, but it can also be quite slow and adds a lot of overhead to the traic.
In some cases it can be benecial to create a TCP-UDP proxy that just sends the payload data over the radio
network. The latency of the connection improves as does the available bandwidth.
This example has the following setup:
An example of how to use the proxy will be presented here. A network consists of 3 SATELLAR devices, one
client and two servers. The IP addresses of the devices are as follows:
All devices have routing tables so that they have IP connectivity. Both server machines have a TCP server
listening at TCP port 502. The Client machine forms a TCP connection over the radio to both of them. The
Client’s conguration would look something like this:
Server 1:
Server 2:
If the proxy is to be used, it needs to be congured in in all SATELLAR devices and the client need to be
First, two proxies must be created in SATELLAR 1, one for each server. Both proxies must listen at dierent
Device IP-Address
Server 1
Server 2
SATEL technical bulletin
ports which can be selected freely. For this example, ports 10000 and 10001 are used. Similarly destination ports
must be selected for the substations, ports 20000 and 20001 will be used here. The proxies in the master would
then look like this:
Then, corresponding proxies must be congured in the other two SATELLAR devices. For SATELLAR 2 like this:
And for SATELLAR 3 like this:
Note that the mode is now UDP to TCP, and the destination Address/Port is that of the corresponding server.
When all proxies have been enabled in the SATELLAR devices, the client can access the two substations with the
following conguration:
Server 1:
Server 2:
The Client computer no longer needs IP routes to the two clients, it only needs to form a TCP connection with