What is t3 protocol in weblogic server?

Solution 1:

Weblogic's implementation of the RMI specification uses a proprietary protocol known as T3. You can think of T3 (and secure T3S) as a layer to expose/allow JNDI calls by clients.

T3 is the protocol used to transport information between WebLogic servers and other types of Java programs. WebLogic keeps track of every Java virtual machine connected to the application. To carry traffic to the Java virtual machine, WebLogic creates a single T3 connection. This type of connection maximizes efficiency by eliminating multiple protocols used to communicate between networks, thereby using fewer operating system resources. The protocol used for the T3 connection also enhances efficiency and minimizes packet sizes, increasing the speed of the delivery method.

Read more: https://docs.oracle.com/cd/E24329_01/web.1211/e24389/rmi_t3.htm#WLRMI143

You can check out some sample client creation code that uses T3 here: http://docs.oracle.com/cd/E11035_01/wls100/client/t3.html

Solution 2:

Normally the T3 protocol is used to interact with the WebLogic console.

According to Oracle's documentation:

RMI communications in WebLogic Server use the T3 protocol to transport data between WebLogic Server and other Java programs, including clients and other WebLogic Server instances. A server instance keeps track of each Java Virtual Machine (JVM) with which it connects, and creates a single T3 connection to carry all traffic for a JVM. See "Configure T3 protocol" in Oracle WebLogic Server Administration Console Help.

For example, if a Java client accesses an enterprise bean and a JDBC connection pool on WebLogic Server, a single network connection is established between the WebLogic Server JVM and the client JVM. The EJB and JDBC services can be written as if they had sole use of a dedicated network connection because the T3 protocol invisibly multiplexes packets on the single connection.
– Source: Using WebLogic RMI with T3 Protocol