Multi-Platform Between Routers

Multi-Platform between routers alleviates the need for an agent in one platform to connect to another platform directly in order for it to send/receive messages from the other platform. Instead with this new type of connection, connections to external platforms will be maintained by the platforms itself and agents do not have the burden to manage the connections directly. This guide will show how to connect three VOLTTRON instances with a fake driver running on VOLTTRON instance 1 publishing to topic with prefix=”devices” and listener agents running on other 2 VOLTTRON instances subscribed to topic “devices”.

Getting Started

Modify the subscribe annotate method parameters in the listener agent (examples/ListenerAgent/listener/ in the VOLTTRON root directory) to include all_platforms=True parameter to receive messages from external platforms.

@PubSub.subscribe('pubsub', '')


@PubSub.subscribe('pubsub', 'devices', all_platforms=True)

or add below line in the onstart method'pubsub', 'devices', self.on_match, all_platforms=True)


If using the onstart method remove the @PubSub.subscribe(‘pubsub’, ‘’) from the top of the method.

After installing VOLTTRON, open three shells with the current directory the root of the VOLTTRON repository. Then activate the VOLTTRON environment and export the VOLTTRON_HOME variable. The home variable needs to be different for each instance.

$ source env/bin/activate
$ export VOLTTRON_HOME=~/.volttron1

Run vcfg in all the three shells. This command will ask how the instance should be set up. Many of the options have defaults and that will be sufficient. Enter a different VIP address for each platform. Configure fake platform driver in the first shell and listener agent in second and third shell.

Terminator Setup

Multi-Platform Configuration

For each instance, specify the instance name in platform config file under it’s VOLTTRON_HOME directory. If the platform supports web server, add the bind-web-address as well.

Here is an example,

Path of the config: $VOLTTRON_HOME/config

vip-address = tcp://
instance-name = "platform1"
bind-web-address =

Instance name and bind web address entries added into each VOLTTRON platform’s config file is shown below.

Multi-Platform Config

Next, each instance needs to know the VIP address, platform name and server keys of the remote platforms that it is connecting to. In addition, each platform has to authenticate or accept the connecting instances’ public keys. We can do this step either by running VOLTTRON in setup mode or configure the information manually.

Configuration and Authentication in Setup Mode


It is necessary for each platform to have a web server if running in setup mode

Add list of web addresses of remote platforms in $VOLTTRON_HOME/external_address.json

External Address Config

Start VOLTTRON instances in setup mode in the three terminal windows. The “-l” option in the following command tells VOLTTRON to log to a file. The file name should be different for each instance.

$ volttron -vv -l volttron.log --setup-mode > volttron.log 2>&1 &

A new auth entry is added for each new platform connection. This can be checked with below command in each terminal window.

$ vctl auth list

Auth Entry

After all the connections are authenticated, we can start the instances in normal mode.

$ ./stop-volttron
$ ./start-volttron

Setup Configuration and Authentication Manually

If you do not need web servers in your setup, then you will need to build the platform discovery config file manually. The config file should contain an entry containing VIP address, instance name and serverkey of each remote platform connection.

Name of the file: external_platform_discovery.json

Directory path: Each platform’s VOLTTRON_HOME directory.

For example, since VOLTTRON instance 1 is connecting to VOLTTRON instance 2 and 3, contents of external_platform_discovery.json will be

    "platform2": {"vip-address":"tcp://",
    "platform3": {"vip-address":"tcp://",

We can obtain the serverkey of each platform using below command in each terminal window:

$ vctl auth serverkey

Contents of external_platform_discovery.json of VOLTTRON instance 1, 2, 3 is shown below.

Multi-Platform Discovery Config

After this, you will need to add the server keys of the connecting platforms using the vctl utility. Type vctl auth add command on the command prompt and simply hit Enter to select defaults on all fields except credentials. Here, we can either add serverkey of connecting platform or type /.*/ to allow ALL connections.


/.*/ allows ALL agent and platform connections without authentication.

$ vctl auth add
domain []:
address []:
user_id []:
capabilities (delimit multiple entries with comma) []:
roles (delimit multiple entries with comma) []:
groups (delimit multiple entries with comma) []:
mechanism [CURVE]:
credentials []: /.*/
comments []:
enabled [True]:
added entry domain=None, address=None, mechanism='CURVE', credentials=u'/.*/', user_id=None

For more information on authentication see authentication.

Once the initial configuration are setup, you can start all the VOLTTRON instances in normal mode.

$ ./start-volttron

Next step is to start agents in each platform to observe the multi-platform PubSub communication behavior.

Start Platform driver on VOLTTRON instance 1

If platform driver is not configured to auto start when the instance starts up, we can start it explicitly with this command.

$ vctl start --tag platform_driver

Start Listener agents on VOLTTRON instance 2 and 3

If the listener agent is not configured to auto start when the instance starts up, we can start it explicitly with this command.

$ vctl start --tag listener

We should start seeing messages with prefix=”devices” in the logs of VOLTTRON instances 2 and 3.

Multi-Platform PubSub

Stopping All the Platforms

We can stop all the VOLTTRON instances by executing below command in each terminal window.

$ vctl shutdown --platform

Platform External Address Configuration

In the configuration file located in $VOLTTRON_HOME/config add vip-address=tcp://ip:port for each address you want to listen on:



The config file is generated after running the vcfg command. The VIP-address is for the local platform, NOT the remote platform.