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Q-in-Q
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Q-in-Q

Q-in-Q is a technology that allows you to create multiple isolated segments within a single VLAN by adding an additional tag to the Ethernet packet header.

With Q-in-Q enabled on a Selectel network, you can pass your VLAN IDs on a port and tags will be delivered over the LAN between your servers.

Q-in-Q customization is needed:

  • for Direct Connect service operation when a trunk port is configured on the operator's side;

  • To configure a trunk port in VMware ESXi on a dedicated server with VMware;

  • to use different VLAN segments on a dedicated server on which virtual servers are deployed. In this case, the dedicated server is privately networked with the virtual server using a global router and tagged traffic with your VLAN IDs is terminated on the global router and routed to the virtual server.

Customize Q-in-Q⁠

  1. Enable Q-in-Q on the switch port.

  2. Select a private subnet.

  3. Configure the network interfaces on the server.

1. Enable Q-in-Q on the switch port⁠

Q-in-Q can only be enabled for a private network.

When Q-in-Q is enabled, there may be a brief private network down time for servers on the selected VLAN.

  1. Create a ticket with a request to enable Q-in-Q. Specify:

    • VLAN numbers can be viewed in the control panel: from the top menu, click Products → Dedicated Servers → Network → VLAN tab → VLAN column;

    • pools where VLANs are located can be viewed in the control panel: in the top menu, click Products → Dedicated Servers → Network → VLAN tab → Pool column.

  2. In the ticket created, wait for a Selectel employee to respond that Q-in-Q is enabled.

2. Select a private subnet⁠

Select an unoccupied subnet whose IP addresses will be used to configure network connectivity. See Standard Private IP Address Ranges for details.

3. Configure the network interfaces on the server⁠

  1. Connect to the server via SSH or via KVM console.

  2. Open the netplan utility configuration file with the vi text editor:

    vi /etc/netplan/01-netcfg.yaml

  3. Add Q-in-Q settings for the network interface of the private network:

    ...
        vlans:
          <eth_name>.<id>:
                id: <id>
                link: <eth_name>
                mtu: 1400
                addresses:
                    - <ip_address>/<mask>

    Specify:

    • <eth_name> — the name of the network interface of the private network;
    • <id> — Q-in-Q tag, you can specify a number from 2 to 4094;
    • <ip_address>/<mask> — IP address from the new private subnet with mask.
    Example of a netplan utility configuration file
    network:
        version: 2
        renderer: networkd
        ethernets:
            eth0:
                addresses: [203.0.113.0/24]
                gateway4: 203.0.113.1
                nameservers:
                    addresses: [198.51.100.1,198.51.101.1]
            eth1:
                addresses: [192.168.0.2/24]
    ...
        vlans:
            eth1.40:
                id: 40
                link: eth1
                mtu: 1400
                addresses:
                    - [10.0.0.15/24]

  4. Press ESC.

  5. Exit the vi text editor with your changes saved:

    :wq

  6. Apply the configuration:

    netplan apply

  7. Optional: reboot the server.