Creating a session between two LUs (an LU-LU session) is a three-stage process. The first stage begins when an LU requests that a session be established. This request is in the form of an SNA Initiate request sent to the SSCP. The SSCP determines whether the LUs are available for sessions. If both LUs are available, a pending active session is created between them. If both LUs are active and connected, and at least one of them is not available (not enabled or at its session limit), and the session-initiation request indicates the session can be delayed until the LUs are available, then a queued session is created. When both LUs are available, the oldest queued session between them becomes a pending active session. Normally, sessions are queued in the order in which the Initiate requests are received. However, the Initiate request can indicate that the session should take priority over other queued sessions, and be put at the head of the queue. The queued session represents a request to establish a session. Queued sessions are not counted against the session limits for the LUs, so there can be many queued sessions waiting for a particular LU to become available.

The second stage begins when the pending active session is created (that is, both LUs are now available for the requested session). The SSCP sends a Control Initiate (CINIT) request to the LU that acts as the PLU in the session being established. The CINIT request is a request sent to the PLU to establish a session by sending a BIND request to the SLU. Pending active sessions are counted against the session limits for the LUs. Therefore, the number of active and pending active sessions for each LU cannot exceed the LU's session limit.

The third stage begins when the BIND request is sent from the PLU to the SLU. The BIND carries information concerning session protocols. The SLU examines the session parameter and if it is acceptable (or in the case of a negotiable BIND, if the SLU wishes to return a set of modified parameters), the SLU sends a positive response to the BIND. When the PLU receives the positive response, the session is considered to be active.