Released: Support for Distributed Network Names (DNN) Listeners for Always On Availability Groups

[Kevin Farlee]

As of SQL Server 2019 CU8, we now support the use of Availability Group Listeners based on Distributed Network Names (DNN Listeners).

DNN listeners are especially useful in Azure VM environments, as they eliminate the need to configure Azure Load Balancers, thus simplifying the configuration and setup.  

DNN resources were introduced to Windows Failover Clusters in Windows Server 2016, and have been available for use with SQL FCIs previously.

Dynamic Network Names are a feature which has been supported in Windows Failover Clusters

To learn more, start with the Availability Group overview topic in the documentation, in a new section about DNN listeners: Availability Group Overview - DNN Listener  

[MicDAI]

Hi. what's the GA date for DNN ?

Any performance comparison between DNN vs using Load balancer ?

[Kevin Farlee]

The feature is GA now. (as of SQL2019 CU8 for availability Groups, CU2 for Failover Cluster Instances).

DNN is only involved in establishing the connection, so there is no difference at all once the connection is established.

My understanding is that failover times will be slightly better, and there should be a very small delta in connection times, mostly due to less network hops through the Load Balancer.

[AnshulDBA]

Does DNN works in Hybrid AG group scenarios? where in we have for example 2 nodes on-premise and one node in Azure.
Any recommended port for DNN configuration?