# AssociateSubnetCidrBlock
<a name="API_AssociateSubnetCidrBlock"></a>

Associates a CIDR block with your subnet. You can only associate a single IPv6 CIDR block with your subnet.

## Request Parameters
<a name="API_AssociateSubnetCidrBlock_RequestParameters"></a>

The following parameters are for this specific action. For more information about required and optional parameters that are common to all actions, see [Common Query Parameters](CommonParameters.md).

 **Ipv6CidrBlock**   
The IPv6 CIDR block for your subnet.  
Type: String  
Required: No

 **Ipv6IpamPoolId**   
An IPv6 IPAM pool ID.  
Type: String  
Required: No

 **Ipv6NetmaskLength**   
An IPv6 netmask length.  
Type: Integer  
Required: No

 **SubnetId**   
The ID of your subnet.  
Type: String  
Required: Yes

## Response Elements
<a name="API_AssociateSubnetCidrBlock_ResponseElements"></a>

The following elements are returned by the service.

 **ipv6CidrBlockAssociation**   
Information about the IPv6 association.  
Type: [SubnetIpv6CidrBlockAssociation](API_SubnetIpv6CidrBlockAssociation.md) object

 **requestId**   
The ID of the request.  
Type: String

 **subnetId**   
The ID of the subnet.  
Type: String

## Errors
<a name="API_AssociateSubnetCidrBlock_Errors"></a>

For information about the errors that are common to all actions, see [Common client error codes](errors-overview.md#CommonErrors).

## Examples
<a name="API_AssociateSubnetCidrBlock_Examples"></a>

### Example
<a name="API_AssociateSubnetCidrBlock_Example_1"></a>

This example associates IPv6 CIDR block `2001:db8:1234:1a00::/64` with subnet `subnet-1a2b3c4d`.

#### Sample Request
<a name="API_AssociateSubnetCidrBlock_Example_1_Request"></a>

```
https://ec2.amazonaws.com/?Action=AssociateSubnetCidrBlock
&SubnetId=subnet-1a2b3c4d
&Ipv6CidrBlock=2001:db8:1234:1a00::/64
&AUTHPARAMS
```

#### Sample Response
<a name="API_AssociateSubnetCidrBlock_Example_1_Response"></a>

```
<AssociateSubnetCidrBlock xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
   <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId> 
   <subnetId>vpc-1a2b3c4d</subnetId>
   <ipv6CidrBlockAssociation>
        <ipv6CidrBlock>2001:db8:1234:1a00::/64</ipv6CidrBlock>
        <ipv6CidrBlockState>
            <state>associating</state>
        </ipv6CidrBlockState>
        <associationId>subnet-cidr-assoc-3aa54053</associationId>
   </ipv6CidrBlockAssociation>
</AssociateSubnetCidrBlock>
```

## See Also
<a name="API_AssociateSubnetCidrBlock_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/ec2-2016-11-15/AssociateSubnetCidrBlock) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ec2-2016-11-15/AssociateSubnetCidrBlock)