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Transit Router

TR instances

Creating a Transit Router instance

Scenarios

When you require private network communication between parts of multiple Virtual Private Clouds (VPCs) or between a VPC and a data center, Transit Router (TR) will help. To configure a TR, first create a TR instance.

Prerequisites

Ensure you have completed VolcanoEngine account registration and real-name authentication.

Complete account recharge and ensure the total value of your VolcanoEngine account balance (cash balance) plus available coupons is equal to or greater than CNY 100. Otherwise, you will be unable to purchase TR or other cloud resources.

Instructions

By default, a single account supports a maximum of 5 TR instances in a single region. If this quota is insufficient, you can request an increase through the Quota Center, up to an absolute upper limit of 10 instances.

Procedure

In the top menu bar, select the target project and region.

Click Create TR and configure related parameters based on the table below.

Parameter	Description	Example
Regions	Select the region for the TR instance.	China (Guangzhou)
Name	Type the name for the TR instance to be created.	tr01
ASN	An Autonomous System (AS) is a network unit on the internet with a unified routing policy, composed of one or more networks and identified by a unique Autonomous System Number (ASN). Specify a private ASN for the TR instance from the range of 64512–65534 or 4200000000–4294967294. When networking within the same region, you can assign any ASN from the specified range for the TR instance. When networking across regions, you must assign different ASNs for TR instances in different regions. When connecting on-premises data centers via a TR and a Direct Connect (DC), the ASNs for the TR and the DC Gateway must be unique. When connecting a single TR instance to multiple DC Gateways to access different data centers, the ASNs for these DC Gateways must also be unique. After being assigned with an ASN, the TR automatically prepends the ASN to the AsPath attribute of routes published to other network instances. tip For cross-region networking scenarios, it is strongly recommended to use different ASNs for Transit Routers in different regions; otherwise, cross-region route propagation may break.	64512
Multicast	Specify whether to enable multicast for the TR instance. Learn more Multicast is a point-to-multipoint communication method that supports data packets sent by one server being received by multiple clients simultaneously. Only TR instances with multicast enabled support multicast configuration. Multicast can only be enabled when creating the TR instance. After creation, this setting cannot be modified.	Check
Related project	Select the project to which the TR instance belongs. After you select a project, only users that have permissions on the project can use the created instance. Learn more If you select All Resources in the top menu bar before entering the creation page, the TR instance belongs to the default project. You can reselect a project as needed. If you select a specific project in the top menu bar before entering the creation page, the TR instance belongs to that project by default. To associate it with another project, change the project to All Resources or the target project in the top menu bar. When you create a TR instance, the system automatically generates a system route table for it. This TR system route table belongs to the same project as the TR instance.	default
Tags	A tag consists of a key-value pair and is used for categorizing and searching resources. Learn more Click Add tag, type the tag key and tag value to add tags to the TR instance.	Tag key: tr-k1 Tag value: tr-v1
Agreement	Follow the console guidance to review and accept the legal terms.	Check

Click Create to complete the action.

Click Go to console to view the created TR instance.

What to do next

When you create a TR instance, the system automatically creates a system route table for it. To forward TR traffic to other network resources (such as a VPC), you also need to create attachments for this TR instance. For procedure, see Intra-region attachments.