Modify VLAN attachments

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This document describes how you can modify VLAN attachments for Partner Interconnect.

The following table lists properties associated with VLAN attachments and describes how to modify the properties.

Property How to modify
Capacity Work with your service provider as described in the Modifying capacity section of this document.
Description and MTU

See Modifying the description and MTU.

Modifications are immediate and don't disrupt traffic.

Whether a VLAN attachment is enabled or disabled To disable or re-enable a VLAN attachment, see Disable VLAN attachments.


BGP IP addresses (Cloud Router IP address, on-premises router IP address)

You can't modify these properties for existing attachments. Instead, you must recreate the VLAN attachment.

To create VLAN attachments for Partner Interconnect, see Creating VLAN attachments.

MD5 authentication (Preview) If you have a Layer 2 connection, follow the steps in Add authentication to an existing session. If you have a Layer 3 connection, contact your service provider for instructions.

The peer ASN is not a property of the VLAN attachment—it is part of the BGP configuration of the Cloud Router. If you have a Layer 2 connection and you want to modify the peer ASN, update the Cloud Router's BGP session for the VLAN attachment.

For more information, see the following resources:

Modify capacity

For an existing VLAN attachment, Google Cloud supports increasing or decreasing the attachment's capacity as your capacity demands rise or fall. Because capacity changes can affect your service provider's network, you must work with them to change your attachment's capacity. Changes in capacity, in rare cases, can cause traffic disruption. If traffic is disrupted, the disruption lasts less than a minute.

After the service provider has updated your attachment, your service provider works with Google to update the attachment's capacity in your Google Cloud project. At that time, Google updates the charges for the attachment based on the new capacity.

For a list of all the service providers, see Supported service providers.

Modify the description and MTU

The section provides instructions for updating the description and MTU of a VLAN attachment.


  1. In the Google Cloud console, go to the Cloud Interconnect VLAN attachments tab.

    Go to VLAN attachments

  2. Select the VLAN attachment to modify.

  3. On the attachment's detail page, click Edit.

  4. Modify the Description of your VLAN attachment, and then click Save.

  5. Optional: Update the maximum transmission unit (MTU) of the attachment. To make use of the 1500-byte MTU, the VPC network using the attachment must have an MTU set to 1500. In addition, the on-premises VMs and routers must have an MTU set to 1500. If your network has the default MTU of 1460, leave the field at 1440.


Modify an interconnectAttachment by specifying the name of the existing VLAN attachment and the attributes to modify:

gcloud compute interconnects attachments partner update NAME \
    --region=REGION \
    --description=DESCRIPTION \

Replace the following:

  • NAME: the name of the existing VLAN attachment
  • REGION: the region of the attachment
  • DESCRIPTION: a description of the attachment
  • MTU: the MTU of the attachment

For more information, see the gcloud compute interconnects attachments partner update reference.

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