# Step 3: Create an Amazon DMS Source Endpoint
<a name="oracle-s3-data-lake-step-3"></a>

In this step, we configure a source endpoint. Amazon DMS uses this endpoint to connect to the source database to read data as well as changes to the data via transaction logs. You can use Extra Connection Attributes for the source endpoint to configure how Amazon DMS captures changes to the data.

After you configure the Amazon Database Migration Service (Amazon DMS) replication instance and the source RDS for Oracle instance, ensure connectivity between these two instances. To ensure that the replication instance can access the server and the port for the database, make changes to the relevant security groups and network access control lists. For more information about your network configuration, see [Setting up a network for a replication instance](https://docs.amazonaws.cn/dms/latest/userguide/CHAP_ReplicationInstance.VPC.html).

 Amazon DMS can stream the changes to the data from `REDO` logs using either Logminer or Binary reader protocols. You can choose this protocol when you create your source endpoint. For detailed comparison on which mode to pickup for CDC replication, see [Using Oracle LogMiner or Binary Reader for CDC](https://docs.amazonaws.cn/dms/latest/userguide/CHAP_Source.Oracle.html#CHAP_Source.Oracle.CDC).

Logminer option is easier to set up. However, since our source Oracle database workload involves ETL jobs that result in high volume of transactions, we choose Binary Reader since it offers better performance for ongoing replication.

After you completed the network configurations, you can create a source endpoint.

 **To create a source endpoint** 

1. Sign in to the Amazon Web Services Management Console, and open the [Amazon DMS console](https://console.amazonaws.cn/dms/v2).

1. Choose **Endpoints**, then choose **Create endpoint**.

1. On the **Create endpoint** page, enter the following information.    
[See the AWS documentation website for more details](http://docs.amazonaws.cn/en_us/dms/latest/sbs/oracle-s3-data-lake-step-3.html)

1. Choose **Create endpoint**.