Hello, in this post we are going to present something that is very important so that you can do all your laboratories on GNS3 without any problem, and this are the Operating System images of the network devices , called commonly IOS images. These are images of the real Operating Systems that are used on physical network devices such as routers, switches, firewalls, and so on, they can be from CISCO or from other vendors like Juniper Juniper images.
So once you get GNS3 installed, the next step is to download the images of the devices you are going to use for your practices and then implement them onto the GNS3 emulator. There are many IOS images of different networks devices on the web, but some of them are the most used on GNS3, to do the networking exercises to practice or prepare CCNA, CCNA or even CCIE and real Labs of networking as if you were working with real network devices, since the images come with all the features supported , for example by a physical router or switch.
Therefore is important to have this images and in this post you will get the links to download therefore following we are going to list all the ISOs that are useful for GNS3 and using in your networking studies.
Here the links to download:. Do you want more IOS images? Don't worry, here we have a good website called "srijit. These images were even tested and checked with the latest version of GNS3, in order to have stable IOS, you can check out the website on the following link:. See you in the coming posts These should not be installed on your router. When choosing a release, Cisco recommends a GD release when possible. Only choose an ED release if your hardware and software features leave you no other choice.
Before you install a new Cisco IOS Software image on your router, check if your router meets the memory requirements for that image. For this, issue the show version command on your router, and look for these lines:. The memory requirements take this into account, so you have to add both numbers to find the amount of DRAM available on your router from a memory requirement point of view.
The , , , and routers have separate DRAM and Packet memory, so you only need to look at the first number. Books Video icon An illustration of two cells of a film strip.
Video Audio icon An illustration of an audio speaker. For example:. Above you can see the file name and MD5 checksum. The checksum can be used to check if the file that you downloaded is the same or has changed. On my flash memory, there are a bunch of configuration files and the current IOS image.
When we want to copy something to or from this router, we have to use the copy command:. I will use the following topology:. Make sure you select the correct directory where you downloaded your IOS image and if you have multiple network interfaces, select the correct interface.
The copy command works in both directions. Figure 1. Table 1. Features in The first planned 15 T new feature release is numbered Release Subsequent releases are defined by an increment of the maintenance rebuild number i. The Services on Demand process enables customers to realize operational savings through ease of software ordering and management.
When an order is placed for a new ISR G2 platform, the router is shipped with a single universal Cisco IOS Software image and a license is used to enable the specific feature set packages, as shown in Figure the figure below. Features are activated through licensing.
Each device ships with Universal image. Each licensing key is unique to a particular device and is obtained from Cisco by providing the product ID and serial number of the router and a Product Activation Key PAK. The PAK is provided by Cisco at the time of software purchase. The IP Base is installed by default. When selecting or upgrading a Cisco IOS router, it is important to choose the proper IOS image with the correct feature set and version.
The Cisco IOS image file is based on a special naming convention. The name for the Cisco IOS image file contains multiple parts, each with a specific meaning. It is important to understand this naming convention when upgrading and selecting a Cisco IOS Software. As shown in Figure 1, the show flash command displays the files stored in flash memory, including the system image files. The most common designation for memory location and compression format is mz. The first letter indicates the location where the image is executed on the router.
The locations can include:. The compression format can be either z for zip or x for mzip. Zipping is a method Cisco uses to compress some run-from-RAM images that is effective in reducing the size of the image. It is self-unzipping, so when the image is loaded into RAM for execution, the first action is to unzip.
Note: The Cisco IOS Software naming conventions, field meaning, image content, and other details are subject to change. On most Cisco routers including the integrated services routers, the IOS is stored in compact flash as a compressed image and loaded into DRAM during boot-up.