Call CreateTransitRouterCidr to create a CIDR block for a transit router - Cloud Enterprise Network - Alibaba Cloud - Cloud Enterprise Network

A transit router CIDR block is a custom CIDR block that you define for a transit router, similar to a CIDR block from which IP addresses are assigned to a router loopback interface. Calls the CreateTransitRouterCidr operation to create a CIDR block for a transit router.

Operation description

A transit router CIDR block is a custom CIDR block that you define for a transit router, similar to a CIDR block from which IP addresses are assigned to a router loopback interface. Transit router CIDR blocks are used to assign addresses to network instance connections. For more information, see Transit router CIDR blocks.

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

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

Only Enterprise Edition transit routers support transit router CIDR blocks.
For usage limits of transit router CIDR blocks, see Usage limits of transit router CIDR blocks.
A maximum of five CIDR blocks can be configured for a transit router. The subnet mask of each CIDR block must be 16 to 24 bits in length.
CIDR blocks of 100.64.0.0/10, 224.0.0.0/4, 127.0.0.0/8, 169.254.0.0/16, or their subnets cannot be created.
Each CIDR block cannot conflict with any CIDR block that needs to communicate within 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, when you create the first VPN connection on the transit router, the system automatically reserves three CIDR blocks from the transit router CIDR block for creating VPN connections in the backend. The system assigns 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 from which IP addresses have been assigned.

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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 supports 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. You can use the client to generate the token, but you must 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 RequestId of the API request as the ClientToken. The RequestId may be different for each API request.	123e4567-e89b-12d3-a456-426****
TransitRouterId	string	Yes	The ID of the transit routing instance.	tr-p0w3x8c9em72a40nw****
RegionId	string	Yes	The region ID of the transit router. You can call the DescribeChildInstanceRegions operation to query the region ID.	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 syntax, and 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 transit router CIDR block.	192.168.10.0/24
PublishCidrRoute	boolean	No	Specifies whether to allow the system to automatically add a route for the transit router CIDR block to the transit router route table. true (default): allows the system to automatically add a route. If you select true, after you create a VPN connection of the private gateway type and create a route learning relationship for the VPN connection, the system automatically adds a route entry to the transit router route table that has a route learning relationship with the VPN connection: A blackhole route whose destination CIDR block is the transit router CIDR block from which gateway IP addresses have been assigned to IPsec connections. This blackhole route is propagated only to the route tables of Virtual Border Router (VBR) instances attached to the transit router. false: does not allow the system to automatically add a route.	true

Response elements

Element	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.
400	InvalidParameter.TransitRouterId	The specified parameter TransitRouterId is invalid.	The parameter TransitRouterId entered is illegal.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.