Juniper Netsim Juniper Netsim is another widely known product that provides a virtual networking environment for practice using Juniper routers and switches.  A comparison of Certexams.comm Juniper Netsim to that of GNS is given below:

Characteristic/Make CertExams Netsim GNS
1Stand alone software Yes No
2Require Subscription to Programs
No No
3Example labs provided Yes

(See available CCNA labs)

4Provides list of commands available Yes

(See available IOS commands)

Requires IOS
Specifically developed with CCNA topic in mind Yes No, it’s generic in nature.
GUI Network Designer Available Yes Yes
Supports both router and switch commands Yes Yes
Installs on Windows computer Yes Yes
Support Available NA
Demo mode Available free Free

Note 1: The Certexams Netsim doesn’t require Junos software as in case of GNS. It is a stand alone software and uses it’s own routing engine simulator. It may be noted that officially, one can’t use JUNOS software outside the device as intended by Juniper Systems.

Note 2: Several labs are provided for thorough preparation. See available

Note 3: All available commands are listed on this page. Just check it out.
Juniper Junos Supported commands

The Juniper Netsim consists of the following modules:

  • Parent framework
  • Simulator
    • Console based
    • GUI based
  • Network Designer
  • Networking Essentials Manual
  • Lab Exercise Manual
  1. Parent Framework: This is the main window that opens after initiating the software. It contains links to all other modules of the Netsim. A screenshot of the same is shown in the figure below. It consists of four parts, namely,  Network Simulator (Console), Network Simulator (GUI), Network Designer (Dran-drop), and Networking manual.

2. Network simulator – Console based: Here you can load any existing lab and try configuration as required using available commands. You can verify configuration by using TCP/IP commands such as ping, tracert, and telnet. Several Junos commands are available for configuring the devices. All commands are console based, in the sense that you need to type in the commands.

3. Network Simulator – GUI based: Configuring the network is similar to that of console based, but you will have GUI (Graphical User Interface) instead of typing the commands. This way, you don’t need to remember the syntax, etc.

4. Network Designer: This module is useful for designing your own labs. A screenshot of the same is shown in the figure below:

As can be seen in the diagram, it consists of two panes. One in the left provides all the devices such as routers, switches, and cables that are available for use. All you need to do is drag and drop the devices as per your requirement and then use appropriate cables to connect those devices. It is recommended that you plan the network diagram before hand. The design area is given in the right pane of the diagram. The device information is available in the lower pane upon selecting the device (not shown in the diagram here).

5. Network Essentials Manual:This provides basics of networking such as IP addressing, binary to hex conversion, TPC/IP troubleshooting commands, Identifying various connector and cable types, etc. If you are a beginner or intend to review the basics, this manual would be of immense help.

6. Labs Manual: This manual is called from the Simulator window. Once the simulator window is initiated (eight console based or GUI based), one can open the labs manual and choose any lab that you want to load. After loading the lab into the simulator window, you can work on configuring the same and troubleshooting. The lab manual provides step by step instructions on how to configure and troubleshoot the network. Several topics have been covered in the labs so that one need not worry about designing one’s own labs. The topics covered include labs on router fundamentals, static routing, policies configuration, RIP, OSPF configurations, dynamic routing labs, labs on firewall and NAT configurations, ipv4 and ipv6 configurations, DHCP, VLAN and VTP, and switch configuration labs. You may view the entire range of available labs here:

The networking simulator is most useful for beginners who want to have hands-on experience in a virtual networking environment without having to buy the real equipment which typically costs 1000s of dollars and very time consuming. Please be cautioned that the virtual networking is limited in scope and may not be used in configuring practical networks or troubleshooting the same.

Check out the Juniper netsim and download a free demo to explore further.