General description

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

It is also possible to perform the operations manually. Refer to your Operating System Network Administration guide for details.

On Red Hat Enterprise Linux 6 & 7 and CentOS 7, the following packages are needed:

bridge-utils - optional
tunctl - optional, need only if command 'ip tuntap' not worked
ethtool - mandatory
vconfig - optional, if VLAN is needed

Using "ncu" utility to establish CHARON virtual network

Login as root and start the ncu utility:

# ncu

CHARON Network Configuration Utility,  Version 1.6. Copyright (C) 2014-2019 STROMASYS SA. 
 
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

Enter "3" to create a bridge between the host physical network adapter and the Linux virtual network interfaces (TAP) and specify the physical network interface ("eth1" in our example) and the number of virtual network interfaces to be created (2 in our example):

Specify the interface to be used for BRIDGE:eth1 How many tap should be created:2 Forming the bridge: ..1..2..3..4..5.. addif tap0 .. addif tap1 ..7..8 done!
Formed bridge br0_eth1 attached over eth1...

 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

:> 7

Now enter "7" to see the created virtual interfaces:

Interfaces Dedicated to State 
---------- ------------ ----- 
eth0 host connected to host 
eth1 bridge disconnected from bridge 
lo host unmanaged from host 
tap0 CHARON connected to host 
tap1 bridge connected to bridge 
================================================================= 
bridge name    bridge id           STP enabled   interfaces 
br0_eth1       8000.22314588acac   no            eth1 
                                                 tap0 
                                                 tap1 
========================== 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

:> 8

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.

Virtual interface creation

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

# tunctl [-t tap<N>]

where “tap<N>” is a name of an instance of the virtual network interface, i.e. “tap0”, “tap1” etc.

Once each virtual network interface instance is created it must be set to promiscuous mode:

# /sbin/ifconfig tap<N> promisc up

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:

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

CHARON-AXP for Linux virtual network

Table of Contents

General description

Using "ncu" utility to establish CHARON virtual network

Virtual interface creation

Usage of the virtual interface in CHARON-AXP configuration