# Creating a Topic

#### Scenarios

A topic serves as a message sending channel, where publishers and subscribers can interact with each other.

You can create your own topic.

#### Creating a Topic

1. Log in to the management console.
2. In the upper left corner, select a region and project.
3. In the service list, select Simple Message Notification.

   The SMN console is displayed.

4. In the navigation pane on the left, choose Topics.

   The Topics page is displayed.

5. Click Create Topic.

   The Create Topic dialog box is displayed.

   Figure 1 Creating a topic
6. Enter a topic name and display name (topic description).

   Table 1 Parameters required for creating a topic
   Parameter | Description
   --- | ---

   Topic Name

   Specifies the topic name, which
   - Contains only letters, digits, hyphens (-), and underscores (_) and must start with a letter or a digit.
   - Must contain 1 to 255 characters.
   - Must be unique and cannot be modified after the topic is created.

   Display Name | Specifies the message sender name, which must be less than 192 characters. NOTE: After you specify a display name in Display name<username@example.com> format, the name you specify will be displayed as the email sender. Otherwise, the sender name will be displayed as username@example.com.

   Tag

   Tags identify cloud resources so that they can be categorized easily and searched quickly.
   - For each resource, each tag key must be unique, and each tag key can have only one tag value.
   - You can enter a maximum of 36 and 43 characters for a tag key and a tag value, respectively. Only digits, letters, hyphens (-), at signs (@), and underscores (_) are allowed.
   - Each topic supports up to 20 tags.

7. Click OK.

   The topic you created is displayed in the topic list.

   After you create a topic, the system generates a uniform resource name (URN) for the topic, which uniquely identifies the topic and cannot be changed.

8. Click a topic name to view the topic details and the total number of topic subscriptions.

#### Follow-up Operations

After you create a topic, add subscriptions. After the subscriptions have been confirmed, alarm notifications will be sent to the subscription endpoints via SMN.

Parent topic: Creating Alarm Notification Topics