What is use of –cluster-advertise=HOST_IP option used to create overlay network

I was able to successfully create an overlay network following the instructions available at https://docs.docker.com/engine/userguide/networking/get-started-overlay/

Could anyone tell me what’s the use of the following option:


I used eth1:2376 as HOST_IP in my environment. Is this information used by overlay network driver? If yes, how/when does it use this information? If not, then who uses it and when?

Thanks much.