CCNA 1.1: Compare and contrast OSI and TCP/IP models (FREE LAB!)


Both the OSI model and the TCP/IP model are general-purpose conceptual models that assist in discussing how computers communicate with each other.

In the 1960's, the U.S. Department of Defense awarded contracts to develop packet switching networks. One of those contracts led to the development of the ARPANET by DARPA (Defense Advanced Research Project Association). They developed the TCP/IP protocol and sent the first successful message from a node at UCLA to a node at Stanford.  The TCP/IP model grew out of these new protocols.

In the 1970's, two international standards bodies (a French committee and the ISO in the U.S.) were working on documents that defined similar models.  In the 1980's those documents merged to become what we know of as the OSI model.


Study notes:

OSI model TCP/IP model
Application (Layer 7) Process/Application Layer
Presentation (Layer 6)
Session (Layer 5)
Transport (Layer 4) Host-to-Host (Transport Layer)
Network (Layer 3) Internet Layer
Data Link (Layer 2) Network Access Layer (Link Layer)
Physical (Layer 1)
  • Both are frameworks to help in understanding network concepts and technologies
  • OSI model is 7 layers, TCP/IP model is 4 layers
  • People talk about the OSI model in terms of a reference model.  Think in terms of the 7 individual layers.
    • Layer 7 - HTTP, FTP
    • Layer 6 - Telnet, X.25
    • Layer 5 - L2TP, PPTP
    • Layer 4 - TCP, UDP
    • Layer 3 - RIP, OSPF
    • Layer 2 - ARP
    • Layer 1 - Ethernet
  • People talk about the TCP/IP model in terms of a protocol stack. Think in terms of applications.
    • Application Layer - FTP, TFTP, Telnet
    • Host-to-Host Layer - TCP, UDP
    • Internet Layer - IPv4, IPv6, ICMP
    • Network Access Layer - ARP, MAC, PPP


PacketTracer Lab: CCNA-1.1-Compare-and-contrast-TCPIP-and-OSI-model.pkt

  • Open the lab and wait about 20-30 seconds to let the devices fully power on before starting the lab.
  • Press Shift+S to enter simulation mode.  This mode will walk you through step by step the packets traversing the network.
  • Select PC0 > Desktop > Command Prompt
  • In the command prompt window telnet to Router0 at
  • In the PacketTracer Simulation Panel under Play Controls, click Capture/Forward 6 times to step through each SYN, SYN-ACK, ACK handshake packets as they traverse from PC0 to the switch to the Router0 and back.
  • In the Simulation panel window, click the colored boxes beside TCP when they appear to view more details about the SYN, SYN-ACK, ACK process.
  • Select the colored information box when the Last Device is SW, the At Device is R0 and the Type is TCP.  Inbound to the Router is destination port 23, source IP and Destination IP  This information is reversed on the outbound layers after being processed by the router.  The protocol shows TCP instead of Telnet because the devices are still  participating in the three-way handshake.
  • Click Capture/Forward 7 more times.  In the command prompt window you will be logged into the router and the router prompt will be displayed
  • As you step through in simulation mode, make note of the device where the packet currently is and view the OSI model layers in both inbound and outbound directions to get a better sense of the layers.  For example, the switch will only display layers 1 and 2 since it it a layer 2 device.  The router will only display layers 1, 2 and 3 since it is a layer 3 device.  The PC will display all 7 layers since that is where the application is running.
  • Try sending and monitoring other types of traffic in the same manner (i.e. ping



  1. Mario Garcia
    Mario Garcia
    May 7, 2019 at 12:11 pm

    Good afternoon, dear

    Along with greeting, I consult how is the dynamics for the weekly laboratories? What access does this give me? and if they vary in any way? and if it also gives me full access to the laboratories of all the points that are seen in the topics:


    • Joe Barger (CCNP/CCDP)
      Joe Barger (CCNP/CCDP) • Post Author •
      May 8, 2019 at 8:31 am

      Weekly and monthly memberships give you access to 65 CCNA labs. With an active membership you can run any of the PacketTracer lab files.
      A list of all topics with labs can be found on the membership page.

  2. joseph yang
    joseph yang
    May 24, 2019 at 1:29 am

    I dont see any TCP . After ICMPs are done, it’s all CDP, tried capturing forward dozens of times

    • Joe Barger (CCNP/CCDP)
      Joe Barger (CCNP/CCDP) • Post Author •
      May 26, 2019 at 10:25 am

      Check the Event List Filters to make sure TCP is enabled. If the envelope icon in PacketTracer is not moving from PC0 to the Switch to the Router you can click “Reset Simulation” and try again. Type exit in the command prompt to get back to C:\> if not already there after resetting the simulation.

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