What is the use GNS3 in cisco? how it useful in cisco?

GNS3 : GRAPHICAL NETWORK STIMULATOR. It allows the combination of virtual and real devices, used to simulate complex networks. It uses Dynamips emulation software to simulate Cisco IOS. GNS3 is used by many large companies including Exxon, Walmart, AT&T and NASA, and is also popular for preparation of network professional certification exams.

CCNA is a very prestigious certification and can land you up in a very good job.But sometimes the only thing which stop people is the cost of hardware. Buying expensive hardware for practicing cisco ccna labs is not possible by everyone . You need to spend $1000 or more for a decent lab .

The solution to this is Using GNS3 and Dynamips. Which lets you simulate routers and switches on your pc. The advantage of this simulator is that it uses real cisco ios , its not like any other simulator which are flash programmed and can run only certain commands.The gns3 can simulate layer 3 devices(Routers) very well but gets buggy sometimes with the layer 2 devices like the switches.

GNS3 - its a simulation software that allows an engineer to simulate and do network configurations before he/she can do on live cisco routers and switches. it allows the administrator to to add real ios images and simulate a network.

GNS3 is a open source used as a graphical network simulator. It allows simulation of complex networks.It is a tool to real labs for CISCO and experiment features of CISCO IOS.

GNS3 is an GUI for the Daynamips emulator.

Simply it is useful to help you implement real word network scenario or LAB.

You can add routers, link them togeather, configure them and check thier behavior.

For me GNS3 is very usefull toolset that allow you to model your network, configuration, behaviour based on Cisco (and not only cisco devices).

I recreated all necessary schemas during planning of projects/optimization of OSPF/BGP/HSRP/VRRP/VRP etc, that is not so easy to create without necessary set of equipment.

Easy to setup, easy to use.

Another benefit - learning. That is next step for practice when you are preparing to CCNP exams (first step is packet tracer, but it is limited in functionality compared to GNS3).

1. It is a program months globally in a simulated network and build a large and professional designs for networks a variety of components and is used by networking students and professional athletes who are preparing for certification (CCNP, CCIE, ... etc.) This program is characterized by including the generality and portability it expanded to include additional networks consisting of Cisco and Juniper and MikroTik, Microsoft, Intel and other companies devices which produces networking devices where you can download the operating any device system before it is used, which provides great flexibility in downloading the appropriate version for each device and access the latest updates for any device features of this program is also great supporting security protocols, encryption, and almost all professional networking needs and director, engineer and student networks. GNS3 features: General dealing with all types of networks and various organs. Full support for all types of network operating systems and updates its technology and sophisticated systems constantly. Cons GNS3: Lack of support from Cisco Soichat completely. The consumption of a large amount of CPU processor of the computer which holds potential.