Dynamic
##################

.. image:: img/Routing-Dynamic.png
    :width: 100%
    :align: center
    :alt: Routing Dynamic

.. image:: img/Routing-Dynamic1.png
    :width: 100%
    :align: center
    :alt: Routing Dynamic

You can configure Dynamic Routing settings in VT AIR.
We use **FRR** to configure the settings in the background.

Please feel free to also look at the extended frr documentation `FRR User Guide <https://frrouting.org/user-guide/>`_.

We support :ref:`BGP`, :ref:`OSPF`, :ref:`OSPFv6`, :ref:`ISIS Settings` and :ref:`BFD Settings`.

General Settings
******************

Please always set a console password.
You will ususally not need it but leaving the console without password leaves you open for security risks.

In order to connect to FRR from the console or bash, you can always use the **vtysh** command without any password.

You can also set **Custom Options** under the advanced settings. They will be copied into the config file on the highest level.

Administrative Distance
***************************

Administrative distance allows the dynamic routing daemon (FRR) to make decisions about what routes should be installed in the rib based upon the originating protocol.
The lowest Admin Distance is the route selected.
This is purely a subjective decision about ordering and care has been taken to choose the same distances that other routing suites have choosen.

.. list-table::
   :widths: 25 25
   :header-rows: 1

   * - Protocol
     - Distance
   * - System
     - 0
   * - Kernel
     - 0
   * - Static
     - 1
   * - EBGP
     - 20
   * - OSPF
     - 110
   * - ISIS
     - 115
   * - IBGP
     - 200

Routes are added based on their admin distance and if having the same admin distance the metric decides the route.
Routes are always added to the VT AIR main routing table with a metric of 20, the internal metric kept in the dynamic routing daemon is not used
to create the route. The internal metric is only for bookkeeping purposes and to redistribute routes to other peers.