.. _BACnet-Router-Addressing:

========================
BACnet Router Addressing
========================

The underlying library that Volttron uses for BACnet supports IP to MS/TP routers. Devices behind the router use a
Remote Station address in the form:

::

    <network>:<address>

where ``<network>`` is the configured network ID of the router and ``<address>`` is the address of the device behind the
router.

For example to access the device at ``<address>`` 12 for a router configured for ``<network>`` 1002 can be accessed with
this address:

::

    1002:12

``<network>`` must be number from **0 to 65534** and ``<address>`` must be a number from **0 to 255**.

This type of address can be used anywhere an address is required in configuration of the :ref:`Volttron BACnet driver
<BACnet-Driver>`.

Caveats
-------

VOLTTRON uses a UDP broadcast mechanism to establish the route to the device.  If the route cannot be established it
will fall back to a UDP broadcast for all communication with the device.  If the IP network where the router is
connected blocks UDP broadcast traffic then these addresses will not work.