Distributed Host Set Up

For each host in a multi-host distributed runtime, the following must occur: * Designate a PolySync Ethernet interface and IP subnet * Determine a unique IP address within the defined subnet * Start PolySync Manager PTP services for clock synchronization ### 1. PolySync Ethernet interface Most machines have at least one Ethernet interface, also known as a Network Interface Card (NIC). To list all available NICs, the developer can use the system command _ifconfig_: ```bash $ ifconfig ``` For machines with a single NIC, the Ethernet interface displayed _eth0_, must be designated as the PolySync Ethernet interface. ### 2. PolySync IP address When using a static network, the DDS Discovery feature will search for other hosts through the selected Ethernet interface. If other hosts exist on the network, developers will be sharing the PolySync bus, which means they will see the other host's data, and vice versa. Once a PolySync IP address is defined it must exist on an Ethernet interface before any PolySync application is run. The most common network configuration solutions define a single subnet for all hosts to communicate on. Advanced users may set the subnet mask and perform more sophisticated networking solutions. When defining hosts on the '200' subnet, it is important to note that all host IP addresses will start with '192.168.200'. Each host defined on the subnet will have a **unique address**. Once an address is selected, use the PolySync Manager to update the PolySync configuration. ```bash $ polysync-manager -s 192.168.200.100 ``` The IP address **must** exist on the host (shown through _ifconfig_ command) before PolySync applications can run. ### 3. SDF IP address Open the SDF Configurator to ensure that the SDF configuration matches the system network configuration. If there is a mismatch detected in the SDF, the **Host Wizard** will open. ```bash $ polysync-sdf-configurator` ``` The last requirement is to run [Precision Time Protocol](/articles/?p=1091) (PTP). Without the PTP service, hosts defined in the PolySync runtime will have differing system times and PolySync data will not be aligned or replayable.