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It is strongly recommended to use only physical network adapters for CHARON-AXP networking to gain maximum performanceperformancesIn situations where the host has only one network adapter, you can use the LINUX Linux virtual network Interfaces ("TUN/TAP") and map individual CHARON-AXP instances to their own virtual interfaces.

There are 2 ways to create the Linux virtual network Interfaces ("TUN/TAP"):

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Using "ncu" utility to establish CHARON virtual network

Login as root . Start and start the "ncu" utility:

# ncu

CHARON Network Configuration Utility, STROMASYS (c) 2016 Version 1.6 

Interfaces Dedicated to State
---------- ------------ -----
eth0 host connected to host
eth1 host disconnected from host
lo host unmanaged from host
=================================================================
bridge name bridge id STP enabled interfaces
========================== VLAN =================================
=================================================================
select action:
1 - Dedicate to CHARON
2 - Release to host
3 - Create Bridge with TAPs
4 - Remove Bridge
5 - Add VLAN
6 - Remove VLAN
7 - Print status
8 - Exit

:> 3

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In the example above we see 2 virtual network interfaces, "tap0" and "tap1", connected to the created bridge. The physical network interface "eth1" is used for the bridge to the virtual network interfaces.

The interfaces "tap0" and "tap1" are ready to be used in CHARON configurations - , they do not need to be additionally dedicated to CHARON.

Enter "8" to quit the "ncu" utility.

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  1. Login as "root" user.

  2. Configure the physical network interface to run in promiscuous mode using the following command. This interface will be dedicated to the whole network bridge (created later).

    # ifconfig eth<N> 0.0.0.0 promisc up

    Promiscuous The promiscuous mode allows the physical (or virtual) network interface to accept the entire volume of incoming packets. This mode is essential for consistency of the information transfer.

  3. In case the firewall is enabled on the host system, the following command should be executed to allow the bridge to forward IP packets:

    # /sbin/iptable -I FORWARD -m physdev --physdev-is-bridged -j ACCEPT

    This command can also be performed from the bridge configuration script. It has to be executed each time the iptables service is (re)started.

    It is also possible to make this setting system-wide. Either:

    1. Issue the given command from the firewall control panel.

    2. Add the following line to the end of the "/etc/sysconfig/iptables" file:

      -I FORWARD -m physdev --physdev-is-bridged -j ACCEPT

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Virtual interface creation

Creation The creation of the desired number of virtual network interfaces (TAPs) can be performed in the following way:

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# /usr/sbin/brctl addif br0 eth<N>
# /usr/sbin/brctl addif br0 tap0

# /usr/sbin/brctl addif br0 tap<N>


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Example:

# /usr/sbin/brctl addif br0 eth1

# /usr/sbin/brctl addif br0 tap0


The proposed configuration assumes one and only one network bridge , so loops are not possible. It is required to turn off the spanning tree protocol with the following command:

# /usr/sbin/brctl stp br0 off

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Starting bridge

To start the created bridge “br0, use the following command:

# /sbin/ifconfig br0 up

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Usage of the virtual interface in CHARON-AXP configuration

Once the “tap<N>” interfaces have been created, the load command maps those interfaces to CHARON-AXP:

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load tap_port/chnetwrk XQA0 interface="tap<N>"

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