CCENT-CCNA:ICND1 100-105 Certification Guide
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Session layer protocols

Unlike the transport layer, the session layer (Layer 5) is responsible for establishing and maintaining the on-demand communication sessions between applications. So, this layer manages and controls the synchronization of data between the applications. The term data is used to represent the PDU at this layer, as shown in Figure 2.11. In this layer, the following communication protocols operate:

  • PPTP operates on port 1723
  • L2TP operates on port 1701