mention mysql replication (pingcap#5422) (pingcap#5501)

mysql-compatibility.md

@@ -10,6 +10,10 @@ TiDB is fully compatible with the MySQL 5.7 protocol and the common features and
 
 However, some features of MySQL are not supported. This could be because there is now a better way to solve the problem (such as XML functions superseded by JSON), or a lack of current demand versus effort required (such as stored procedures and functions). Some features might also be difficult to implement as a distributed system.
 
+- In addition, TiDB does not support the MySQL replication protocol, but provides specific tools to replicate data with MySQL.
+    - Replicate data from MySQL: [TiDB Data Migration (DM)](https://docs.pingcap.com/tidb-data-migration/stable/overview) is a tool that supports the full data migration and the incremental data replication from MySQL/MariaDB into TiDB.
+    - Replicate data to MySQL: [TiCDC](/ticdc/ticdc-overview.md) is a tool for replicating the incremental data of TiDB by pulling TiKV change logs. TiCDC uses the [MySQL sink](/ticdc/ticdc-overview.md#sink-support) to replicate the incremental data of TiDB to MySQL.
+
 > **Note:**
 >
 > This page refers to general differences between MySQL and TiDB. Refer to the dedicated pages for [Security](/security-compatibility-with-mysql.md) and [Pessimistic Transaction Model](/pessimistic-transaction.md#difference-with-mysql-innodb) compatibility.