Cisco 3750 Switch Ios For Gns3 Tutorial
I’ve been getting questions about switches in GNS3 so decided to write this article explaining which switching protocols you can or cannot use in GNS3. First of all, it’s impossible to run switches in GNS3! That being said the option that we do have is using the NM-16SW switching module in a router which gives us some capabilities.
Now you are probably wondering ‘which capabilities’ so let’s have a look what we can do. You might have noticed that in the newer versions of GNS3 there’s a Etherswitch Router. This is a Cisco 3725 with the NM-16SW module so only the icon is different. Now let’s see what “switching” options we have. Vlan interfaces: You can create vlan interfaces which can be used as the default gateway for clients. For example interface vlan 10 with IP address 10.10.10.10 and interface vlan 20 with IP address 20.20.20.20. This is the same as you would do on any L3 switch like the 3550 or 3560.
Trunking: Trunking is looking good, the only encapsulation type is 802.1Q which is fine (no ISL). But you are able to setup a trunk connection just fine. There is no dynamic auto or dynamic desirable mode so now way to lab this. Vlan Trunking Protocol (VTP): VTP is working just like on a switch, you can configure the VTP domain, mode like server / client / transparent, pruning and passwords. Etherchannel: If you want to learn etherchannel you are better off with some real switches, you can enable it but there’s no Lacp or Pagp support.
Spanning-Tree: You can learn the basics of spanning-tree, see which ports are in blocking and forwarding mode but don’t expect any fancy stuff. To be honest you are better of with real switches to study spanning-tree if you ask me. Switched Port Analyzer: Should be possible but to be honest I didn’t fully test it yet. The commands are there so I believe it should work just fine.
Cisco Switches Ios For Gns3
Storm Control: Storm control is there and seems to be just fine. Quality of Service (QOS): The switch commands for Qos are there like “mls qos” and you can configure the mls qos maps. This looks cool to me! So what do I think of it? To be honest I like it a bit better after researching all the commands and what the options are. If you want to play with vlans or vlan interfaces there’s nothing wrong using the NM16-SW module.
Trunking is fine, you can do everything that you want as long as you don’t care about ISL. VTP is the same thing as on a real switch so no need for real hardware here. Etherchannel I don’t like since there’s no Lacp or Pagp support, the same for spanning-treeyou lack a lot of commands and there’s no way to switch to other modes like MST which you can do on a real switch. SPAN is excellent and I also like Storm Control and the Quality of Service commands.
So what should you do? Get real switches or use GNS3? If you have no budget and are studying for CCNA, just use GNS3.
If you do have some money to spend get 2 or 3 Cisco 2950’s and you will have more fun. If you are studying for CCNP SWITCH just get yourself a 3550 and a 2950 or something. It’s not too expensive and using a real switch is better.
For the CCIEdo yourself a favor and invest in 2x 3560 and 2x 3550 and connect them to a breakout switch or get quad-nics. You’ll be spending a LOT of time studying and it’s better to spend your time at switches than the NM16-SW module. If you want to know all the options for the NM16-SW module check out this article on the Cisco website: Next time i’ll be writing an article how to connect your real physical switches to your GNS3 topology. So what do you think? Is there anything i’m missing?
Please share your opinion in the comments!
The GNS3 website and forum is an amazing resource of information, labs and tips, the people on the forum are al there to support each other and help improve the GNS3 and others ability to use it. Here is a link to a post about IOS images. Here's a guide to how Cisco IOS images are named: Please remember that the Cisco IOS image is a copyrighted piece of intellectual property and so you will need to obtain a way of getting them yourself if you don't have a Cisco CCO log in. I therefore cannot suggest you search the internet using sites like, I don't know, Google, for them as that would be wrong, so I won't do that. Here's a link to the main GNS3 website: The guys at GNS3 are always looking for suggestions and peoples feedback and so your contribution on their forum would be very welcome, especially as someone new to it!
Mark9586 wrote: On a GNS3 note, last time I used it (about 4 years ago) on both Ubuntu and Windows, it would max the processor out on the PC with just a handful of routers running. Has that been improved? For the CPU uusage, you can right click each different router model, and select 'set idle PC', this calculates the best setting and you should really select the vlaue with a. If a value in the dropdown box doesn't have a., select a value and then do it again. I can easily run 20 routers with about 30% usage on a 8 core AMD Bulldog motherboard..