# Shared attachments in AWS Cloud WAN
<a name="cloudwan-shared-attachments"></a>

You can share attachments on any of your shared core networks. For more information on sharing core networks, see [Shared AWS Cloud WAN core network](cloudwan-share-network.md).

 When a core network owner shares their core network with your account, you are then able to create new VPC, transit gateway route table, or Direct Connect gateway attachments for the shared core network. You can also view the current attachments or delete an attachment from the shared core network.

**Note**  
A shared core network currently supports only VPC, transit gateway route table, and Direct Connect gateway attachments.

**Topics**
+ [Create a shared VPC attachment](cloudwan-vpc-share-create.md)
+ [Create a shared transit gateway route table attachment](cloudwan-tgw-share.md)
+ [Create a shared Direct Connect gateway attachment](cloudwan-dx-share.md)
+ [View shared attachments](cloudwan-shared-view.md)

# Create a shared VPC attachment in an AWS Cloud WAN core network
<a name="cloudwan-vpc-share-create"></a>

 Use the AWS Network Manager console to create a shared VPC attachment that can be used across accounts.

**To create a shared VPC attachment**

1. Access the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. Under **Connectivity**, choose **Global Networks**.

1. On the **Global networks** page, choose the global network ID.

1. In the navigation pane, under **Shared by me**, choose **Attachments**.

1. Choose **Create attachment**.

1. Enter a **name** to identify the attachment.

1. From the **Core network** dropdown list, choose the core network that is shared with you and that is where you want to create the VPC attachment.

1. From the **Edge location** dropdown list, choose the location where the attachment is located.

1. From the **Attachment type** dropdown list, choose **VPC**.

1. Optionally choose any of the following:
   + Choose **Appliance mode support** if appliance mode is supported. For more information about appliance mode, see [Appliance mode](cloudwan-vpc-attachment.md#cloudwan-appliancemode).
   + Choose **IPv6 support** if the attachment supports IPv6.
   + By default, **DNS support ** is enabled. This allows domain name system resolution for the attachment. Clear the check box if you don't want to enable DNS support. For more information, see [DNS support](cloudwan-vpc-attachment.md#cloudwan-dns-support).
   + By default **Security Group Referencing support** is enabled. When you create a VPC attachment, Cloud WAN automatically enables security group referencing for VPCs attached to the same core network edge. This allows you to reference security groups across VPCs in your security group rules. Clear the check box if you don't want to enable security group referencing. For more information, see [Security group referencing](cloudwan-vpc-attachment.md#cloudwan-sg-referencing).

1. Choose the **VPC ID**. You're then prompted to choose the **Availability Zone** and **Subnet Id** in which to create the core network VPC attachment. The Availability Zones that are listed are those edge locations that you chose when you created your core network. You must choose at least one Availability Zone and subnet ID. 

1. (Optional) In the **Tags** section, add **Key** and **Value** pairs to help identify this resource. You can add multiple tags by choosing **Add tag**, or remove any tag by choosing **Remove tag**.

1. Choose **Create attachment**.

1. The **Attachment** page displays the following information about your shared attachments:
   + **Attachment ID**
   + **Name**
   + **Edge location**
   + **Resource Type**
   + **Resource ID**
   + **State**
   + **Core network**
   + **Core network status**

1. Choose **Create attachment** to create a new shared VPC attachment.

# Create a shared transit gateway route table attachment in an AWS Cloud WAN core network
<a name="cloudwan-tgw-share"></a>

The following steps guide you through creating a shared transit gateway attachment.

**To create a shared transit gateway attachment**

1. Access the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. Under **Connectivity**, choose **Global Networks**.

1. On the **Global networks** page, choose the global network ID.

1. In the navigation pane, under **Shared by me**, choose **Attachments**.

1. Choose **Create attachment**.

1. Enter a **name** to identify the attachment.

1. From the **Core network** dropdown list, choose the core network that is shared with you and that is where you want to create the VPC attachment.

1. From the **Edge location** dropdown list, choose the location where the attachment is located.

1. In the **VPC attachment** section, choose **IPv6 support** if the attachment supports IPv6.

1. From the **Attachment type** dropdown list, choose **Transit gateway route table**.

1. From the **Transit gateway peering** dropdown list in the **Transit gateway route table attachment** section, choose an existing peering to share.

1. (Optional) In the **Tags** section, add **Key** and **Value** pairs to help identify this resource. You can add multiple tags by choosing **Add tag**, or remove any tag by choosing **Remove tag**.

1. Choose **Create attachment**.

1. The **Attachment** page displays the following information about your shared attachments:
   + **Attachment ID**
   + **Name**
   + **Edge location**
   + **Resource Type**
   + **Resource ID**
   + **State**
   + **Core network**
   + **Core network status**

1. Choose **Create attachment** to create the new shared VPC or transit gateway attachment. See [Attachments in AWS Cloud WAN](cloudwan-create-attachment.md).

# Create a shared Direct Connect gateway attachment in an AWS Cloud WAN core network
<a name="cloudwan-dx-share"></a>

The following steps guide you through creating a shared Direct Connect gateway attachment.

**To create a shared Direct Connect gateway attachment**

1. Access the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. Under **Connectivity**, choose **Global Networks**.

1. On the **Global networks** page, choose the global network ID.

1. In the navigation pane, under **Shared by me**, choose **Attachments**.

1. Choose **Create attachment**.

1. Enter a **Name** identifying the attachment.

1. From the **Core network** drop-down list, choose the core network that you want to associate the Direct Connect gateway with.

1. From the **Attachment type** drop-down list choose **Direct Connect gateway attachment**.

1. For the **Edge locations**, choose one of the following:
   + **All** — Choose this option if you want to associate all edge locations in your core network with the Direct Connect gateway. When choosing this option, any new edge locations deployed in a core network policy version are automatically added to the Direct Connect gateway attachment and updated with the Direct Connect gateway. This does not automatically update any edge locations you might remove from the core network policy. 
   + **Specific** — Choose this option if you want to associate only a subset of edge locations from your core network policy with the Direct Connect gateway. When choosing this option, you must manually add new or remove edge locations to the Direct Connect gateway attachment after deploying a core network policy version. A Direct Connect attachment will be attached to the core network edge according to the core network policy edge locations but will associated to the segment based on the segment edge locations.

1. In the** Direct Connect gateway attachment **section, choose the Direct Connect gateway to use for connecting Direct Connect to the Cloud WAN core network. 
**Note**  
A Direct Connect gateway can be used for only one core network, and can't be used for any other Direct Connect gateway type. If the attachment between the Direct Connect gateway and the core network is removed, the gateway becomes available for other Direct Connect association types.

1. Choose **Create attachment**.

# View shared AWS Cloud WAN attachments
<a name="cloudwan-shared-view"></a>

View details about your shared VPC and transit gateway attachments.

**To view shared VP and transit gateway attachments**

1. Access the Network Manager console at [https://console.aws.amazon.com/networkmanager/home/](https://console.aws.amazon.com/networkmanager/home).

1. Under **Connectivity**, choose **Global Networks**.

1. On the **Global networks** page, choose the global network ID.

1. In the navigation pane, under **Shared by me**, choose **Attachments**.

1. The **Attachment** page displays the following information about your shared attachments:
   + **Attachment ID**
   + **Name**
   + **Edge location**
   + **Resource Type**
   + **Resource ID**
   + **State**
   + **Core network**
   + **Core network status**

1. Select the check box for the specific attachment that you want to view. Details about the attachment are displayed on the lower part of the page.

1. (Optional) You can edit some of the attachment information:

   1. Choose the attachment, and then choose **Edit**.

   1. On the **Edit attachment** page, you can edit the subnet configuration and the tags.

   1. If you made any changes to update the attachment, choose **Edit attachment**. The **Attachments** page displays a confirmation that the attachment was modified successfully.