CreateTransitRouterCidr - Cloud Enterprise Network - Alibaba Cloud Documentation Center

Operation description

A transit router CIDR block is a custom CIDR block that you can create for a transit router. It is similar to a CIDR block used to assign an IP address to a router's loopback interface. A transit router CIDR block is used to allocate IP addresses to network instance connections. For more information, see Transit router CIDR blocks.

The CreateTransitRouterCidr operation is used to add a CIDR block to a transit router only after the transit router is created.

Before you create a transit router CIDR block, note the following information:

Only Enterprise Edition transit routers support CIDR blocks.
For more information about the limits on transit router CIDR blocks, see Limits on transit router CIDR blocks.
A transit router supports up to five CIDR blocks. The subnet mask of each CIDR block must be 16 to 24 bits in length.
You cannot create CIDR blocks that are within 100.64.0.0/10, 224.0.0.0/4, 127.0.0.0/8, or 169.254.0.0/16, or their subnets.
Each CIDR block must not conflict with the CIDR blocks of interconnected network instances in the Cloud Enterprise Network (CEN) instance.
Each CIDR block must be unique within the same CEN instance.
After you add a CIDR block to a transit router and create the first VPN connection on it, the system automatically allocates three CIDR blocks from the specified CIDR block. These three CIDR blocks are reserved by the system for creating VPN connections. The system then allocates IP addresses to IPsec connections from the remaining CIDR blocks.

You can call the ListTransitRouterCidrAllocation operation to query the CIDR blocks that are reserved by the system or allocated to IPsec connections.

Try it now

Try this API in OpenAPI Explorer, no manual signing needed. Successful calls auto-generate SDK code matching your parameters. Download it with built-in credential security for local usage.

Test

RAM authorization

The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.
API: The API that you can call to perform the action.
Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.
Resource type: The type of the resource that support authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.
- For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.
- For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.
Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.
Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

Action

Access level

Resource type

Condition key

Dependent action

cen:CreateTransitRouterCidr

create

*TransitRouter

acs:cen:*:{#accountId}:centransitrouter/{#centransitrouterId}

None

Request parameters

Parameter	Type	Required	Description	Example
ClientToken	string	No	The client token that is used to ensure the idempotence of the request. Generate a token on your client to make sure that the token is unique among different requests. The token can contain only ASCII characters. Note If you do not specify this parameter, the system automatically uses the request ID as the client token. The request ID is different for each request.	123e4567-e89b-12d3-a456-426****
TransitRouterId	string	Yes	The ID of the transit router.	tr-p0w3x8c9em72a40nw****
RegionId	string	Yes	The ID of the region where the transit router is deployed. Call the DescribeChildInstanceRegions operation to query region IDs.	cn-hangzhou
Name	string	No	The name of the transit router CIDR block. The name can be empty or 1 to 128 characters in length, and cannot start with http:// or https://.	nametest
Description	string	No	The description of the transit router CIDR block. The description can be empty or 1 to 256 characters in length, and cannot start with http:// or https://.	desctest
DryRun	boolean	No	Specifies whether to perform a dry run. Valid values: true: performs a dry run. The system checks the required parameters, request format, and service limits. If the request fails the dry run, an error message is returned. If the request passes the dry run, the `DryRunOperation` error code is returned. false (default): performs a dry run and sends the request. If the request passes the dry run, the transit router CIDR block is created.	false
Cidr	string	Yes	The CIDR block of the transit router.	192.168.10.0/24
PublishCidrRoute	boolean	No	Specifies whether to allow the system to automatically add a route that points to the transit router CIDR block to the route table of the transit router. true (default): Yes. After you create a VPN connection that uses a private VPN gateway and enable route learning for the connection, the system automatically adds a blackhole route to the route table of the associated transit router. The destination of this route is the transit router CIDR block. The transit router CIDR block is the CIDR block from which a gateway IP address is allocated to the IPsec connection. This blackhole route is advertised only to the route tables of virtual border routers (VBRs) that are connected to the transit router. A blackhole route whose destination CIDR block is the transit router CIDR block, which refers to the CIDR block from which gateway IP addresses are allocated to the IPsec-VPN connection. The blackhole route is advertised only to the route tables of virtual border routers (VBRs) connected to the transit router. false: No.	true

Response parameters

Parameter	Type	Description	Example
	object	The response parameters.
TransitRouterCidrId	string	The ID of the transit router CIDR block.	cidr-0zv0q9crqpntzz****
RequestId	string	The request ID.	0876E54E-3E36-5C31-89F0-9EE8A9266F9A

Examples

Success response

JSON format

{
  "TransitRouterCidrId": "cidr-0zv0q9crqpntzz****",
  "RequestId": "0876E54E-3E36-5C31-89F0-9EE8A9266F9A"
}

Error codes

HTTP status code	Error code	Error message	Description
400	OverLappingExist.Cidr	The cidr overlapping exist.	The error message returned because CIDR overlapping is already enabled.
400	OperationUnsupported.TransitRouterCidr	Transit region does not support the operation.	The error message returned because this operation is not supported in the specified region.
400	IllegalParam.Cidr	The specified cidr is invalid.	The error message returned because the specified CIDR block is invalid.
400	IllegalParam.RegionId	The specified RegionId is illegal.	The error message returned because the specified region is invalid.
400	InstanceNotExist	The instance is not exist.	The error message returned because the specified instance does not exist.
400	InvalidTransitRouterMode.NeedUpgrade	TransitRouter need to upgrade.	The error message returned because the specified transit router mode is not supported.
400	IncorrectStatus.TransitRouterInstance	The status of TransitRouter is incorrect.	The error message returned because the transit router is in an invalid state.
400	InvalidParameter	Invalid parameter.	The error message returned because the parameter is set to an invalid value.
400	Unauthorized	The AccessKeyId is unauthorized.	The error message returned because you do not have the permissions to perform this operation.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.