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    Express Connect:DescribeExpressConnectRouterAssociation

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    Express Connect:DescribeExpressConnectRouterAssociation

    Last Updated:Jun 04, 2026

    Lists the virtual private clouds (VPCs) and transit routers (TRs) associated with an Express Connect Router (ECR).

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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

    expressconnectrouter:DescribeExpressConnectRouterAssociation

    list

    *ExpressConnectRouter

    acs:expressconnectrouter::{#accountId}:expressconnectrouter/{#EcrId}

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    EcrId

    string

    Yes

    The ID of the Express Connect Router instance.

    ecr-mezk2idmsd0vx2****
    AssociationId

    string

    No

    The ID of the association between the Express Connect Router and the VPC or TR.

    ecr-assoc-9p2qxx5phpca2m****
    AssociationRegionId

    string

    No

    The region ID of the associated VPC or TR.

    cn-hangzhou
    AssociationNodeType

    string

    No

    The type of the associated resource. Valid values:

    • VPC: A VPC.

    • TR: A transit router.

    VPC
    VpcId

    string

    No

    The ID of the VPC instance.

    vpc-bp1h37fchc6jmfyln****
    TransitRouterId

    string

    No

    The ID of the transit router instance.

    tr-2ze4i71c6be454e2l****
    CenId

    string

    No

    The ID of the Cloud Enterprise Network instance.

    cen-of3o1the3i4gwb****
    NextToken

    string

    No

    The token for the next page of results. Valid values:

    • Leave this parameter empty for the first request.

    • For subsequent requests, set this parameter to the NextToken value from the previous response.

    AAAAAYws9fJ0Ur4MGm/5OkDoW/Zn0J0/sCjivzwX9oBcwFnWaaas/kSG+J/WzLOxJHS4****
    MaxResults

    integer

    No

    The maximum number of entries to return per page. Valid values: 1 to 2147483647. Default value: 20.

    20
    DryRun

    boolean

    No

    Specifies whether to perform a dry run. Valid values:

    • true: Performs a dry run to check the request. No resources are modified.

    • false (default): sends a normal request.

    false
    ClientToken

    string

    No

    A client token to ensure the idempotence of the request.

    The token must be unique across requests and contain only ASCII characters.

    Note

    If you omit this parameter, the system uses the request's RequestId as the ClientToken. Each RequestId is unique.

    02fb3da4-130e-11e9-8e44-00****

    Response elements

    Element

    Type

    Description

    Example

    object

    RpcResponse

    RequestId

    string

    The request ID.

    05130E79-588D-5C40-A718-C4863A59****
    Success

    boolean

    Indicates whether the request was successful. Valid values:

    • True: The request was successful.

    • False: The request failed.

    True
    Code

    string

    A value of 200 indicates that the request was successful. Other values indicate a failure. For more information, see the error codes.

    200
    Message

    string

    The response message.

    OK
    HttpStatusCode

    integer

    The HTTP status code.

    200
    DynamicCode

    string

    The dynamic error code.

    IllegalParamFormat.EcrId
    DynamicMessage

    string

    The dynamic error message that is used to replace the %s placeholder in the value of the ErrMessage parameter.

    Note

    If ErrMessage returns The Value of Input Parameter %s is not valid and DynamicMessage returns EcrId, the value of the EcrId request parameter is invalid.

    The param format of EcrId **** is illegal.
    AccessDeniedDetail

    string

    The details about the access denial.

    Authentication is failed for ****
    TotalCount

    integer

    The total number of entries returned.

    1
    MaxResults

    integer

    The number of entries returned per page.

    20
    NextToken

    string

    A pagination token. It can be used in the next request to retrieve a new page of results. Valid values:

    • If NextToken is empty, no next page exists.

    • If NextToken is not empty, it indicates that the next page of results is available.

    AAAAAYws9fJ0Ur4MGm/5OkDoW/Zn0J0/sCjivzwX9oBcwFnWaaas/kSG+J/WzLOxJHS4****

    AssociationList

    array<object>

    The list of associations.

    array<object>

    AssociationId

    string

    The ID of the association between the Express Connect Router and the VPC or the TR.

    ecr-assoc-9p2qxx5phpca2m****

    RegionId

    string

    The region ID of the resource.

    cn-hangzhou
    OwnerId

    integer

    The ID of the Alibaba Cloud account to which the resource belongs.

    167509154715****
    GmtCreate

    string

    The time when the association was created. The time is displayed in the YYYY-MM-DDThh:mm:ssZ format. It is expressed in Coordinated Universal Time (UTC).

    2024-01-09T12:18:23Z
    GmtModified

    string

    The time when the association was modified. The time is displayed in the YYYY-MM-DDThh:mm:ssZ format. It is expressed in Coordinated Universal Time (UTC).

    2024-01-09T12:18:23Z
    Status

    string

    The status of the association. Valid values:

    • CREATING: The resource is being created.

    • ACTIVE: The resource is available for use.

    • INACTIVE: The Express Connect Router is associated with the TR, but the association from the TR is pending.

    • ASSOCIATING: The resource is being associated.

    • DISSOCIATING: The resource is being disassociated.

    • UPDATING: The resource is being updated.

    • DELETING: The resource is being deleted.

    ACTIVE
    AssociationNodeType

    string

    The type of the associated resource. Valid values:

    • VPC: VPC

    • TR: TR

    VPC
    TransitRouterOwnerId

    integer

    The ID of the Alibaba Cloud account that owns the TR.

    189159362009****

    TransitRouterId

    string

    The ID of the TR instance.

    tr-2ze4i71c6be454e2l****

    CenId

    string

    The ID of the CEN instance.

    cen-5510frtx8zi54q****
    VpcOwnerId

    integer

    The ID of the Alibaba Cloud account that owns the VPC.

    146757288406****
    VpcId

    string

    The ID of the VPC instance.

    vpc-2zeeaxet4i2j1a7n7****
    AllowedPrefixes

    array

    The list of allowed prefixes.

    string

    The allowed prefix.

    192.0.**.**/28
    EcrId

    string

    The ID of the Express Connect Router instance.

    ecr-fu8rszhgv7623c****
    AllowedPrefixesMode

    string

    The prefix-based routing mode. Valid values:

    • MatchMode: match mode

    • IncrementalMode: incremental mode

    MatchMode
    Description

    string

    The description of the association.

    test

    Tags

    array<object>

    The tags of the association.

    object

    Key

    string

    The tag key.

    Value

    string

    The tag value.

    TransitRouterName

    string

    The name of the TR instance.

    VpcName

    string

    The name of the VPC instance.

    Examples

    Success response

    JSON format

    {
  "RequestId": "05130E79-588D-5C40-A718-C4863A59****",
  "Success": true,
  "Code": "200",
  "Message": "OK",
  "HttpStatusCode": 200,
  "DynamicCode": "IllegalParamFormat.EcrId",
  "DynamicMessage": "The param format of EcrId **** is illegal.",
  "AccessDeniedDetail": "Authentication is failed for ****",
  "TotalCount": 1,
  "MaxResults": 20,
  "NextToken": "AAAAAYws9fJ0Ur4MGm/5OkDoW/Zn0J0/sCjivzwX9oBcwFnWaaas/kSG+J/WzLOxJHS4****\n",
  "AssociationList": [
    {
      "AssociationId": "ecr-assoc-9p2qxx5phpca2m****\n",
      "RegionId": "cn-hangzhou",
      "OwnerId": 0,
      "GmtCreate": "2024-01-09T12:18:23Z",
      "GmtModified": "2024-01-09T12:18:23Z",
      "Status": "ACTIVE",
      "AssociationNodeType": "VPC",
      "TransitRouterOwnerId": 0,
      "TransitRouterId": "tr-2ze4i71c6be454e2l****\n",
      "CenId": "cen-5510frtx8zi54q****",
      "VpcOwnerId": 0,
      "VpcId": "vpc-2zeeaxet4i2j1a7n7****",
      "AllowedPrefixes": [
        "192.0.**.**/28"
      ],
      "EcrId": "ecr-fu8rszhgv7623c****",
      "AllowedPrefixesMode": "MatchMode",
      "Description": "test ",
      "Tags": [
        {
          "Key": "",
          "Value": ""
        }
      ],
      "TransitRouterName": "",
      "VpcName": ""
    }
  ]
}

    Error codes

    HTTP status code

    Error code

    Error message

    Description
    400 MissingParam.%s The param of %s is missing. The request parameters are not specified. Please check the corresponding parameters and try again.
    400 IllegalParamFormat.%s The param format of %s is illegal. Illegal parameter format
    400 IllegalParam.%s The param of %s is illegal. Illegal parameter
    404 ResourceNotFound.EcrId EcrId not found. ECR instance does not exist

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.