All Implemented Interfaces:
Closeable, AutoCloseable, LifecycleComponent, org.elasticsearch.core.Releasable, Transport

public class Netty4Transport extends TcpTransport
There are 4 types of connections per node, low/med/high/ping. Low if for batch oriented APIs (like recovery or batch) with high payload that will cause regular request. (like search or single index) to take longer. Med is for the typical search / single doc index. And High for things like cluster state. Ping is reserved for sending out ping requests to other nodes.