In the OSI communications model, the Session layer manages the creation and removal of the association between two communicating network end points. This can also be called a connection.

A connection is maintained while the network end points are communicated between each other in a conversation or session of some unknown length of time. Some connections and sessions only need to last long enough to send a message or a piece of data in one direction. In addition, some sessions may last longer, this typically occurs when one or both of the network end points are  able to terminate it the connection.

The transport layer ensures that messages/data are delivered without errors, in sequence, and with no data content losses or data content duplications. It relieves the Session Layer from any concern with the transfer of data between them and their peers.

Examples:

• Session Layer
  • This layer acts like a manager and asks one of its employees (Transport Layer) to move a piece of data/message from one network end-point to another.
• Transportation Layer
  • This layer takes the request of the Session Layer and moves the data as insturcted, it also double checks the data for any missing or corrupted information after it has been moved. If for some reason the new data does not match the old data then the Transport player will attempt to move the data gain until the data at both locations is in sync.