A Smart Proxy subscribing Nexus - the subscriber - needs two different types of connections to the smart proxy publisher Nexus.
1) The subscriber needs to ask the publisher at what IP address and port should it connect to establish a trusted secure connection over which to receive events. This address is known as the publisher Advertised URI. The subscriber asks the question by sending a special HTTP request to the http/https Remote URL value already specified in the subscriber's proxy repository configuration. The Remote URL is also used when downloading files from the remote server.
2) After receiving the Advertised URI from step 1 from the publisher, the subscriber attempts to establish a secure TLS TCP based socket connection direct to the publisher using that dedicated IP/host address and port. Once established, over this channel it will receive cache expiry event information for that remote repository.
The Advertised URI on publisher must advertise an IP address/host name that is routable such that a tcp connection can be made to from an external source/subscribing Nexus.