From the previous chapter, we know that JK uses a TCP port to communicate with the JBoss EAP6 server via AJP13 protocols. When compared with JK, mod_cluster uses the following three channels to serve its functions:
A connector channel supports the multiple protocols for the load balancer to proxy user requests to worker nodes. This part is almost synonymous with JK. The difference here is that besides the AJP13 protocol, mod_cluster also supports the HTTP/HTTPS protocols.
An advertising channel discovers worker nodes. This channel uses IP multicasting to transfer UDP datagrams. The load balancer will advertise itself in a multicast group, and the worker nodes will find it automatically by subscribing to this group.
A management channel is used to transfer status and management messages between the load balancer and the worker nodes. The protocol used by the management channel is an extension of the HTTP/1.1 protocol. The name of the protocol is MCMP.
When compared...