CentOS 8.x Configure ethernet port for 802.3 encapsulated trunk traffic communication

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CentOS 8.x Configure ethernet port for 802.3 encapsulated trunk traffic communication

There is old article on this at Configuring ethernet port in trunk mode

On a trunk port there can be multiple tagged VLAN traffic. We can access traffic of a particular VLAN on a sub-interface. To create a sub-interface we need to create sub-interface configuration file using:

1. To access traffic of a particular VLAN on a sub-interface, create sub-interface configuration file '/etc/sysconffig/network-scripts/ifcfg-<interface-name>.<vlan-id>'.

   Example name /etc/sysconfig/network-scripts/ifcfg-eth0.101 if interface eth0 is in trunk mode with VLAN 101 traffic coming tagged.

   DEVICE=eth0.101
   NAME=eth0.101
   VLAN=yes
   BOOTPROTO=static  #Or BOOTPROTO="none" or BOOTPROTO="DHCP", etc.
   ONBOOT=yes
   IPADDR=""
   NETMASK=""
   GATEWAY=""
   DNS1=""
   DNS2=""

   and so on as per requirement.

2. Restart network and see if sub-interface is up and running as expected

   nmcli networking off; nmcli networking on

3. In case you do not see device eth0.101 up and working then try command:

   vconfig eth0 add 101

   and then again restart network using nmcli.

Refer: https://www.snel.com/support/802-1q-vlan-tagging-in-centos-8/ esp. if you want to use ip routing 2 along with sub-interfaces.

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