|  | 13.1 | The Session Layer
| 13.1.3 | Dialogue control

The session layer decides whether to use two-way simultaneous conversation or two-way alternate communication. This decision is referred to as dialogue control. If two-way simultaneous communication is allowed, then the session layer does little in the way of managing the conversation. In these cases, other layers of the communicating computers manage the conversation. It is possible to have session layer collisions, although these are very different than the media-collisions that occur in Layer 1. At this level, collisions can only occur as two messages pass each other, and cause confusion in either, or both, communicating hosts.

If these session layer collisions are intolerable, then dialogue control has another option: - two-way alternate communication. Two-way alternate communication involves the use of a session layer data token that allows each host to take turns. This is similar to the way a Layer 2 Token Ring handles Layer 1 collisions.