The Session layer in OSI - Study Notes for PSC, SSC, and IBPS IT Officer Exams

Updated on January 04, 2026

Welcome to the Computer Science and Technology Study Materials section from CoreNetworkZ EdTech Solutions, a leading mock test and competitive exam preparation platform, for students preparing for SSC, DSSSB, and Kerala PSC examinations. Today, I will explain the Session Layer and its functions.

The session layer is the fifth layer in the OSI reference model. It responds to service requests from the Presentation layer and issues service requests to the Transport layer. This tutorial explains the role of the Session layer in a network and its critical functions.



Where is The Session Layer?

The session layer is between the Transport and Presentation layers in the OSI reference model.


You cannot find a session layer in the TCP/IP model.


If someone asks where is the Session layer in a TCP/IP model, answer them there is no separate session layer in that model. The Application layer in the TCP/IP model handles the role of the session layer.



What Does The Session Layer Do?

One of our readers, Mohammed Salman, asked the purpose of the Session Layer. Let me explain it.

The primary function of the Session layer is to create, maintain, and terminate sessions. The session layer is also responsible for finding and sending data across the correct connection.


The Session layer communicates with the Transport layer to set up and tear down the connection.


We will learn more about the importance and working of the Session layer by studying its functions. The functions of the Session layer are listed below.

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How does This Study Material help PSC, SSC, and DSSSB Aspirants?

SSC, DSSSB, and Kerala PSC conduct examinations for various IT posts.

Understanding the Session layer is essential for candidates appearing for the DSSSB PGT/TGT Computer Science, Kerala PSC Degree Level Exam, SSC Scientific Assistant (CS), VSSC Technical Assistant, and System Analyst posts. These networking fundamentals are core parts of the Computer Science syllabus.

Kerala PSC Degree Level examinations have a Computer Science section where students can expect questions from the Session layer. You can check the Kerala PSC Degree Level Common Prelims Syllabus under the Computer Science section. I recommend you download the syllabus using this official link.

Reference: https://www.keralapsc.gov.in/sites/default/files/2021-02/syllubus.pdf

The Functions of the Session Layer are:

Jessy George asked me to write the functions of the Session Layer in the comment section. Thanks for that question Jessy, and you can read the four functions below.


  1. It starts and ends a session across a network.

  2. Allows applications to share information.

  3. Ensures that information is flowing to the right place.

  4. Communicate to the presentation layer and Transport layer.

Another question you may hear is about the maximum number of sessions supported by the Session layer in a network. The answer is simple. A session layer is there because it handles multiple sessions at a time.


We can have multiple sessions on a network due to the Session layer.


Let me explain it with a practical example. We are seeing a movie where sound and sight both should match. It is one of the applications of the Session layer.


You have learned about the working and functions of the Session layer. We will complete this tutorial by providing the list of protocols in this layer.



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List of Session layer protocols

Navneeth Gopan, in the comment section, asked for a few protocols working in this layer. Well Navneeth, here is a list of ten Session Layer protocols.

  1. AppleTalk Data Stream Protocol (ADSP)
  2. AppleTalk Session Protocol (ASP)
  3. Call Control Protocol for Multimedia Communication
  4. Internet Storage Name Service
  5. Network Basic Input Output (NetBIOS)
  6. Password Authentication Protocol (PAP)
  7. Point-to-Point Tunneling Protocol (PPTP)
  8. Remote Procedure Call Protocol (RPC)
  9. Short Message Peer-to-Peer (SMPP)
  10. Secure Shell (SSH)

Reference

For those researching this topic, CoreNetworkZ EdTech Solutions recommends the following references.

  1. https://learningnetwork.cisco.com/s/article/osi-model-reference-chart
  2. https://www.keralapsc.gov.in/sites/default/files/2021-02/syllubus.pdf
  3. https://community.cisco.com/t5/network-management/the-session-layer-of-the-osi-model/td-p/429434

Author: Alex George

Author

Alex George is the Chief Editor and founder of CoreNetworkZ EdTech Solutions. He is a software engineer and has 20 years of experience in the EdTech niche.

He graduated with a B.Tech in Computer Science & Engineering from CUSAT and worked with three leading IT companies before starting CoreNetworkZ EdTech Solutions.

He possesses sound knowledge of SOHO Network Engineering and has completed various IT certifications, including CCNA, RHCE, and CEH.

He developed and published more than twenty professional custom themes for Blogger and is an expert in software app development.

You can contact him at alex.george@corenetworkz.com.

10 comments:

  1. Jeremy6:54 AM

    Hi Alex,

    Does Session Layer support any protocols? If so, which are they?

    ReplyDelete
    Replies
    1. Hello Jeremy,

      I have published the list of protocols.

      Delete
  2. David Fletcher6:56 AM

    Hello Alex,

    I came from your community profile on SystoSys. I like your writing style and you are doing a wonderful job.

    ReplyDelete
    Replies
    1. Thank you for your compliments David.

      Delete
  3. Jessy George8:47 AM

    Hi Alex George, what are the functions of the OSI Session layer?

    ReplyDelete
    Replies
    1. I have explained the functions in the article.

      Delete
  4. Navneeth Gopan8:48 AM

    Alex,

    I am preparing for CCNA. Can you share a few protocols working in Session layer?

    ReplyDelete
    Replies
    1. Hello Navneeth,

      They are mentioned in the article.

      Delete
  5. Mohammed Salman8:50 AM

    What is the purpose of this session layer in the OSI Reference Model?

    ReplyDelete
    Replies
    1. Hello Mohammed,

      The purpose of this layer is to create, maintain, and terminate sessions.

      Delete

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