This article describes how to increase the size of an existing VLAN on a Network Domain.

Recommended reading: Introduction to IP Addressing in MCP 2.0


  1. VLANs are only available in MCP 2.0 Data Center locations. For an overview, see Understanding MCP 1.0 vs. MCP 2.0 Data Center Locations
  2. You must have already deployed a VLAN in order to expand its size. See How to Deploy a VLAN on a Network Domain
  3. The VLAN which you wish to expand must be on a CIDR boundary ( can be expanded, cannot).
  4. The expansion of the VLAN can't overlap space with the Network Domain SNAT address.
  5. The expansion of the VLAN must not overlap with the Outside Transit VLAN Subnet of the same Network Domain. For details refer to Introduction to IP Addressing and Routing in MCP 2.0.
  6. The expansion of the VLAN can't overlap space with the IP range of any other VLANs in the same Network Domain.
  7. VLANs with HIGH Gateway Addressing cannot be expanded. see How to Deploy a VLAN on a Network Domain
  8. The new private IPv4 space associated with the VLAN expansions cannot currently have any private IPv4 addresses used as a Virtual Listener or a NAT destination.
  9. VLANs cannot be expanded if they have any Nodes or NICs that are currently assigned IPv4 addresses of x.x.x.4 and x.x.x.5 in the first octet of the VLAN range.
  10. Small VLANs cannot be expanded
  11. For Detached VLANS:
    1. You can expand a Detached VLAN regardless of size
      1. This means Detached VLANs even of sizes /25 through /30 can be expanded. 
  12. For Attached VLANs:
    1. Private IPv4 Base Address and Private IPv4 Prefix Size of the expanded VLAN cannot match any existing Static Routes on any Detached VLANs on the same Network Domain
  13. You cannot expand a non-RFC 1918 Attached VLAN if there is a client SNAT Exclusion that defines the exact same IP range as the expanded size


  1. From the Home page, Select the Data Center which contains the Network Domain where you want to expand an existing VLAN:


  2. Click on the Network Domain where you want to expand the existing VLAN:


  3. Click on the VLANs and Servers tab to expand the menu:

  4. Locate the VLAN that you want to expand from the list of deployed VLANs. Click on the Manage gear  associated with that VLAN, then select Expand VLAN from the drop-down menu:

    Note: If the VLAN has High Gateway Addressing, the Expand VLAN button will be unavailable and the system will present an error message indicating that it can not be expanded:

    Note: Small size VLANs can not be expanded. The Expand VLAN button will be unavailable and the system will present an error message indicating that it can not be expanded::

  5.  The Expand VLAN dialog will be displayed:

    Note: The Blue Information box indicates the current Host Address Range (current size), as well as which sizes the VLAN can be expanded to:

    Note: You can not edit any information besides the Subnet Mask from this dialog.

  6. Select the desired expanded size for the VLAN from the Subnet Mask* drop-down menu:

  7. Once the new Subnet Mask has been selected, the blue Information box will be updated to indicate what the expanded size of the VLAN will be, as well as any remaining options for future expansion, if applicable:

    Note: Once a VLAN has been expanded, it can not be reduced. 
  8. Click Expand. The system will display a confirmation message:

  9. The system will expand the VLAN. Progress will be shown in the VLAN bar:

  10. Once the process has completed, the system will display a success message, and the VLAN will return to a normal state:

  11. Note: In rare cases, it is possible for an Expand VLAN attempt to fail. Either REASON_10 or REASON_20 indicate a non-recoverable failure occurred when attempting to expand the VLAN. If this situation occurs, you must open a Support Case to address the issue. Until the issue is addressed, any additional attempts to add, expand, or delete Cloud Networks (MCP 1.0) or Cloud Network Domains (MCP 2.0) or VLANs (MCP 2.0) in the same Geographic Region will fail and you will receive the message that another network operation is in progress. Generate an Administrator Log report to view the error code. See How to View an Administrator Logs Report