Support : Knowledge base

Knowledge Base

Welcome to OPAL-RT’s Knowledge Base

OPAL-RT offers a repository of support information for optimal use of its technology.

Loading…

Please note that OPAL-RT knowledge base is not fully optimized for mobile platforms.

For optimal experience, use a desktop computer.

Reference Number: AA-01178// Views: AA-01178// Created: 2016-06-13 21:02:00// Last Updated: 2017-11-27 18:59:07
Problem & Solution
Problem configuring multiple Ethernet ports: not able to ping IP addresses on Ethernet ports other than eth0

Problem

I try to configure multiple Ethernet ports for my simulator (using an external Quad Port Ethernet Card or not) but I cannot ping the target when connected physically (from my PC) to target Ethernet ports other than eth0. Actually, when connected physically to an Ethernet port other than eth0, I cannot ping any of the IP addresses that I defined but when connected physically to eth0, I can ping all the IP addresses I defined.

 

Solution

This problem happens since all IP addresses you defined are in the same Subnet (same sub-network). By default, all IP addresses in the same Subnet will pass through eth0. Ethernet ports must not be able to detect each other; they need to be in different Subnets. For the Ethernet ports to be in different subnets, the third number of the IP address must be different (ex: 192.168.10.101 and 192.168.11.101) and the the Subnet Masks must be 255.255.255.0. 

In the following example, eth0 and eth1 do not detect each other. If you want to connect to eth0, your PC (or other device) IP address will need to be 192.168.10.xxx and its Subnet mask 255.255.255.0. To connect to eth1, your PC (or other device) IP address will need to be 192.168.11.xxx and its Subnet mask 255.255.255.0. Obviously, the Ethernet cable will need to be plugged in the correct Ethernet port, accordingly. The same concept is true if you use more Ethernet ports with an external Quad Port Ethernet Card.

eth0 

IP address: 192.168.10.101 

Subnet Mask: 255.255.255.0

eth1

IP address: 192.168.11.101 

Subnet Mask: 255.255.255.0


See the following KB article for further info on how to correctly separate the Ethernet communication protocols traffic from RT-LAB Probe Control traffic in distinct networks.