cloud: update region CIDR docs

tidb-cloud/changefeed-sink-to-mysql.md

@@ -35,7 +35,7 @@ If your MySQL service is in an AWS VPC that has no public internet access, take
 1. [Set up a VPC peering connection](/tidb-cloud/set-up-vpc-peering-connections.md) between the VPC of the MySQL service and your TiDB cluster.
 2. Modify the inbound rules of the security group that the MySQL service is associated with.
 
-    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-project-cidr) to the inbound rules. Doing so allows the traffic to flow from your TiDB Cluster to the MySQL instance.
+    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-cidr-for-a-region) to the inbound rules. Doing so allows the traffic to flow from your TiDB Cluster to the MySQL instance.
 
 3. If the MySQL URL contains a hostname, you need to allow TiDB Cloud to be able to resolve the DNS hostname of the MySQL service.
 
@@ -48,7 +48,7 @@ If your MySQL service is in a Google Cloud VPC that has no public internet acces
 2. [Set up a VPC peering connection](/tidb-cloud/set-up-vpc-peering-connections.md) between the VPC of the MySQL service and your TiDB cluster.
 3. Modify the ingress firewall rules of the VPC where MySQL is located.
 
-    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-project-cidr) to the ingress firewall rules. Doing so allows the traffic to flow from your TiDB Cluster to the MySQL endpoint.
+    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-cidr-for-a-region) to the ingress firewall rules. Doing so allows the traffic to flow from your TiDB Cluster to the MySQL endpoint.
 
 ### Load existing data (optional)
 

tidb-cloud/create-tidb-cluster.md

@@ -61,11 +61,12 @@ If you are in the `Organization Owner` or the `Project Owner` role, you can crea
 
     2. Configure the [cluster size](/tidb-cloud/size-your-cluster.md) for TiDB, TiKV, and TiFlash (optional) respectively.
     3. Update the default cluster name and port number if necessary.
-    4. If this is the first cluster of your current project and CIDR has not been configured for this project, you need to set the project CIDR. If you do not see the **Project CIDR** field, it means that CIDR has already been configured for this project.
+    4. If CIDR has not been configured for this region, you need to set the CIDR. If you do not see the **Project CIDR** field, it means that CIDR has already been configured for this region.
 
         > **Note:**
         >
-        > When setting the project CIDR, avoid any conflicts with the CIDR of the VPC where your application is located. You cannot modify your project CIDR once it is set.
+        > - TiDB Cloud will create a VPC with this CIDR when the first cluster in this region is created. All the subsequent clusters of the same project in this region will use this VPC.
+        > - When setting the CIDR, avoid any conflicts with the CIDR of the VPC where your application is located. You cannot modify your CIDR once the VPC is created.
 
 4. Confirm the cluster and billing information on the right side.
 

tidb-cloud/migrate-from-mysql-using-data-migration.md

@@ -120,7 +120,7 @@ If your MySQL service is in an AWS VPC, take the following steps:
 
 2. Modify the inbound rules of the security group that the MySQL service is associated with.
 
-    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-project-cidr) to the inbound rules. Doing so allows the traffic to flow from your TiDB cluster to the MySQL instance.
+    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-cidr-for-a-region) to the inbound rules. Doing so allows the traffic to flow from your TiDB cluster to the MySQL instance.
 
 3. If the MySQL URL contains a DNS hostname, you need to allow TiDB Cloud to be able to resolve the hostname of the MySQL service.
 
@@ -140,7 +140,7 @@ If your MySQL service is in a Google Cloud VPC, take the following steps:
 
 3. Modify the ingress firewall rules of the VPC where MySQL is located.
 
-    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-project-cidr) to the ingress firewall rules. This allows the traffic to flow from your TiDB cluster to the MySQL endpoint.
+    You must add [the CIDR of the region where your TiDB Cloud cluster is located](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-cidr-for-a-region) to the ingress firewall rules. This allows the traffic to flow from your TiDB cluster to the MySQL endpoint.
 
 </details>
 

tidb-cloud/set-up-vpc-peering-connections.md

@@ -13,41 +13,39 @@ To connect your application to TiDB Cloud via VPC peering, you need to set up [V
 
 VPC peering connection is a networking connection between two VPCs that enables you to route traffic between them using private IP addresses. Instances in either VPC can communicate with each other as if they are within the same network.
 
-Currently, TiDB Cloud only supports VPC peering in the same region for the same project. TiDB clusters of the same project in the same region are created in the same VPC. Therefore, once VPC peering is set up in a region of a project, all the TiDB clusters created in the same region of this project can be connected in your VPC. VPC peering setup differs among cloud providers.
+Currently, TiDB clusters of the same project in the same region are created in the same VPC. Therefore, once VPC peering is set up in a region of a project, all the TiDB clusters created in the same region of this project can be connected in your VPC. VPC peering setup differs among cloud providers.
 
 > **Tip:**
 >
 > To connect your application to TiDB Cloud, you can also set up [private endpoint connection](/tidb-cloud/set-up-private-endpoint-connections.md) with TiDB Cloud, which is secure and private, and does not expose your data to the public internet. It is recommended to use private endpoints over VPC peering connections.
 
-## Prerequisite: Set a Project CIDR
+## Prerequisite: Set a CIDR for a region
 
-Project CIDR (Classless Inter-Domain Routing) is the CIDR block used for network peering in a project.
+CIDR (Classless Inter-Domain Routing) is the CIDR block used for creating VPC for TiDB Dedicated clusters.
 
-Before adding VPC Peering requests to a region, you need to set a project CIDR for your project's cloud provider (AWS or Google Cloud) to establish a peering link to your application's VPC.
+Before adding VPC Peering requests to a region, you must set a CIDR for that region and create an initial TiDB Dedicated cluster in that region. Once the first Dedicated cluster is created, TiDB Cloud will create the VPC of the cluster, allowing you to establish a peering link to your application's VPC.
 
-You can set the project CIDR when creating the first TiDB Dedicated of your project. If you want to set the project CIDR before creating the cluster, perform the following operations:
+You can set the CIDR when creating the first TiDB Dedicated cluster. If you want to set the CIDR before creating the cluster, perform the following operations:
 
 1. Log in to the [TiDB Cloud console](https://tidbcloud.com).
 2. Click <MDSvgIcon name="icon-left-projects" /> in the lower-left corner, switch to the target project if you have multiple projects, and then click **Project Settings**.
 3. On the **Project Settings** page of your project, click **Network Access** in the left navigation pane, and then click the **Project CIDR** tab.
-4. Click **Add a project CIDR for AWS** or **Add a project CIDR for Google Cloud** according to your cloud provider, specify one of the following network addresses in the **Project CIDR** field, and then click **Confirm**.
+4. Click **Create CIDR**, and then click **AWS CIDR** or **Google Cloud CIDR** according to your cloud provider. Specify the region and CIDR value in the **Create AWS CIDR** or **Create Google Cloud CIDR** window, and then click **Confirm**.
 
     > **Note:**
     >
-    > To avoid any conflicts with the CIDR of the VPC where your application is located, you need to set a different project CIDR in this field.
+    > - To avoid any conflicts with the CIDR of the VPC where your application is located, you need to set a different project CIDR in this field. 
+    > - For AWS Region, it is recommended to configure an IP range size between `/16` and `/23`. For Google Cloud Region, it is recommended to configure an IP range size between `/16` and `/21`. Supported network addresses include:
 
-    - 10.250.0.0/16
-    - 10.250.0.0/17
-    - 10.250.128.0/17
-    - 172.30.0.0/16
-    - 172.30.0.0/17
-    - 172.30.128.0/17
+    - 10.0.0.0 - 10.255.255.255 (10/8 prefix)
+    - 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
+    - 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
 
     ![Project-CIDR4](/media/tidb-cloud/Project-CIDR4.png)
 
 5. View the CIDR of the cloud provider and the specific region.
 
-    The region CIDR is inactive by default. To activate the region CIDR, you need to create a cluster in the target region. When the region CIDR is active, you can create VPC Peering for the region.
+    The CIDR is inactive by default. To activate the CIDR, you need to create a cluster in the target region. When the region CIDR is active, you can create VPC Peering for the region.
 
     ![Project-CIDR2](/media/tidb-cloud/Project-CIDR2.png)
 
@@ -183,7 +181,7 @@ You can also use the AWS dashboard to configure the VPC peering connection.
 
         ![Search all route tables related to VPC](/media/tidb-cloud/vpc-peering/aws-vpc-guide-4.png)
 
-    3. Right-click each route table and select **Edit routes**. On the edit page, add a route with a destination to the Project CIDR (by checking the **VPC Peering** configuration page in the TiDB Cloud console) and fill in your peering connection ID in the **Target** column.
+    3. Right-click each route table and select **Edit routes**. On the edit page, add a route with a destination to the TiDB Cloud CIDR (by checking the **VPC Peering** configuration page in the TiDB Cloud console) and fill in your peering connection ID in the **Target** column.
 
         ![Edit all route tables](/media/tidb-cloud/vpc-peering/aws-vpc-guide-5.png)
 

tidb-cloud/terraform-use-cluster-resource.md

@@ -267,7 +267,7 @@ In the results:
 
 > **Note:**
 >
-> Before you begin, make sure that you have set a Project CIDR in the TiDB Cloud console. For more information, see [Set a Project CIDR](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-project-cidr).
+> Before you begin, make sure that you have set a CIDR in the TiDB Cloud console. For more information, see [Set a CIDR](/tidb-cloud/set-up-vpc-peering-connections.md#prerequisite-set-a-cidr-for-a-region).
 
 You can create a cluster using the `tidbcloud_cluster` resource.