## Network Configuration How To Guide

The purpose of this how-to guide is to configure the network your Per Vices Crimson TNG or Cyan SDR device is on. Your SDR device boasts several network ports: the management (MGMT) port(s) is used to configure the device, and the SPF+ ports are used to send data. The operating system used in configuring the device used here is Arch Linux. We will cover the following:

For a visual guide of the overall configuration procedure, see figure shown below:

##### Figure 1: Overall Network Port Configuration Procedure

Note

If you would like to configure a custom Crimson TNG or Cyan MGMT IP address using how to configure a custom management IP address, you will need to reflect these changes when following this network configuration how to guide.

## Part 1: Identifying the Network Interfaces

The first part of this how-to guide is to identify that your host system’s network interfaces map to the physical ports (MGMT, Data SFP+ ports) on your Per Vices SDR transceiver (Crimson TNG, Cyan, custom). The following is how to ensure that the MGMT and SFP+ physical ports are correctly identified by your host systems network interface card (NIC). Two methods to do this are shown below.

### 1.1. Visual Identification by Blinking

The first method is to use software called ethtool. However, your NIC may not be supported by this, and you will have to use the steps in 1.2.

Note

You will need to download and install ethtool. You should be able to install ethtool using your distribution specific package manager.

Note

In case you ever unplug the unit, you may want to write down the information obtained using the below procedure on a piece of tape, and stick it to the host system so you always know which interface maps to which port on the Crimson TNG or Cyan device.

You will first need to identify all the interfaces on your host system. This can be accomplished using the following command in a Linux console:

$ip address show Each interface will be prefixed by “en” after running the above command. Next, you can check which interface from the host system corresponds to what physical port using ethtool. Use the following command to do this: $ sudo ethtool -p <interface> 120

The interface which you specified should now blink on your host system for 2 minutes. Once you have identified this physical interface, you can connect the ethernet cable from it to the desired port on your Per Vices SDR, and make note of interface name.

### 1.2. Visual Identification by LED

The second method is to use trial and error to ensure the correct network interfaces are identified. The following steps should be taken to ensure this:

1. Power on your Crimson TNG

2. Wait for the unit to fully boot (all LEDS are solid green)

3. For each management and data cable, do the following steps in sequence, in order to uniquely identify the cable you have attached from the host system to the desired port:

a. Type the following command:

 bash
$sudo ip link set up <interface>   b. Wait 10 seconds c. See whether the LED is turned on your host systems NIC d. Then, type the following command: $ sudo ip link set down <interface> 

e. See whether the LED is turned off on the host system NICs

f. If the LED turns on and off when you enable/disable (up/down) the interface, then you have correctly located the interface.

4. Move onto the next interface, beginning from 3.

## Part 2: Configure Interfaces

$sudo ip address add <IP_address/prefix_len> broadcast + dev <interface> The default IP addresses of the ports on the Crimson TNG device can be found in Table 1. The suggested host interface specifications for Crimson TNG are located in Table 2. The default IP addresses of the ports on the Cyan unit can be found in Table 1. The suggested host interface specifications for Cyan are located in Table 2. For example, below we are configuring the SPF+ A port/cable on Crimson TNG to the suggested host IP address/prefix_len (10.10.10.10/24) using the network adapter (enp1s0f0). $ sudo ip address add 10.10.10.10/24 broadcast + dev enp1s0f0

Alternatively, for Ubuntu users, this can also be accomplished with the GUI by going into network settings, as shown in Figure 2 below:

##### Figure 2: Ubuntu Network Settings.

From there, you can click on the desired Ethernet port you intend to configure, and then put the correct Address, Netmask and Gateway values, as shown in Figure 3 below:

### 2.2. Configuring the Correct MTU

Next, set the maximum transmission unit (MTU). This is an important step; without properly setting the MTU, transmission will not work properly. Use the following command to do so:

$sudo ip link set mtu 9000 dev <SFP+ A Interface>$ sudo ip link set mtu 9000 dev <SFP+ B Interface>
You will need to repeat this for other SFP+ devices depending on which SDR device you are configuring.