# Mappings View

Mappings describe the data flow from one topic to another, such as the data flow between devices and processing rules.

See also: [Cybus::Mapping resource](https://docs.cybus.io/2-0-6/documentation/services/service-commissioning-files/resources/cybus-mapping)

## Overview

<figure><img src="https://639096190-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FfDpOJO2upcq5EpoSahvK%2Fuploads%2Fgit-blob-23eddc49cad164ec7565926e6ad6997bbf7ccde5%2Fmappings_overview.png?alt=media" alt=""><figcaption><p>Connections Overview</p></figcaption></figure>

In the list, all mappings are displayed with the following information:

**Service ID**

* The unique identifier of the service that contains this mapping.

**Name**

* The name of the mapping.

**Entries**

* The number of entries for the mapping.

**Agent**

* The agent that is assigned to the mapping.

**Status**

* The current state of the mapping (e.g., enabled or enabling).

## Mapping Details View

* To open the **Mappings View** for a specific service, click **Services** > **Service Overview** and select a service. In the **Service Details** view of the selected service, click the **Mappings** tab.

<figure><img src="https://639096190-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FfDpOJO2upcq5EpoSahvK%2Fuploads%2Fgit-blob-8696fe0434ed07cf5de5d557580f089152e3c509%2Fmappings_details_view.png?alt=media" alt=""><figcaption><p>Mapping Details View</p></figcaption></figure>

At the top of the **Mapping Details View**, the following information is displayed:

**Mapping ID**

* The unique identifier of the service that contains this mapping.

**Service ID**

* The unique identifier of the service that contains this mapping.

**Entries**

* The number of entries for the mapping.

**Agent**

* The agent that is assigned to the mapping.

**Status**

* The current state of the mapping (e.g., enabled or enabling).

## Resources of Mappings

Each mapping has resources itself.

* To open the resources of mappings, click a mapping in the **Mappings View**.

See also: [Cybus::Mapping resource](https://docs.cybus.io/2-0-6/documentation/services/service-commissioning-files/resources/cybus-mapping)

{% hint style="warning" %}
For reliable operation, MQTT shared subscriptions are not supported in the **Entries tab**, as they could interfere with other clients subscribed to the same topics.
{% endhint %}

<figure><img src="https://639096190-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FfDpOJO2upcq5EpoSahvK%2Fuploads%2Fgit-blob-73956274d8d78815e07a920a9a6dc1a79f98216c%2Fmappings_details_shared_subscriptions.png?alt=media" alt=""><figcaption></figcaption></figure>

**Subscribe**

* The resource that the mapping subscribes data from.

**Subscribe Broker**

* Indicates which message broker is used to receive the subscribed data (e.g., internal).

**Publish**

* The resource that the mapping publishes data to. You can click the entry to open the details view of the resource.

**Publish Broker**

* Indicates which message broker is used to publish the data (e.g., internal).

**Rules**

The **Rules tab** lists associated Rule Engine rules for the mapping. The rules define how data should be processed between subscribing and publishing. For more information, see [Rule Engine](https://docs.cybus.io/2-0-6/documentation/services/rule-engine).

### Search

The search allows you to filter the list.

* Minimum search length is 3 characters.
* Search services by service ID or name.
* Search resources by name, ID, protocol, parent resource ID, agent name, or service ID.
* Search is case-insensitive.