gns3 switching

The nm-16esw module has very limited switching support. If you want to do switching in GNS3 better use the new version 1.1 and use IOU.

I've been using the 16 port switch module, can you explain what IOU is, and why it's better?

IOU is Ios on Unix, it offers almost full switch simulation without taking much cpu resources. you use a virtual linux machine on your computer which holds the IOU images, its a bit tricky to install but if you have it running its much much better than the nm16 module.

check out my blog in my signature, i have written an install guide just today.

hi, ive been checking your blog and it looks really great.. i havent try it yet.. im just wondering if the CLI of IOU is similar to the IOS??

once integrated into GNS3 the IOU images just behave like any other IOS device image, expect you are cannot add interfaces as far as i know.

but they have more than enough interfaces to do everything you will ever need.

I imported the OVA file into virtualbox, set it as host only adapter, but it doesn't get an IP address, so I can't go to upload my IOU image.

be sure to check firewall/antisvirus settings, try to log on with username root and password cisco and use the ifconfig command to assign an ip address manually

What about ram mem for this ova file.. can i use just 512 or it as to be 2048???

i reduced the amout to 512 and ran a lil test for you, the vm starts up and i didnt notice any problems when throwing in 3 switches and setting up a lil spanning tree scenario, however i dont know how stuff will be if you add a truckload of devices, but i assume that reducing the amount of ram might lead to some slowdowns/crashes when creating huge topologies. however for 3-4 switches it is probably just fine.

Alright, so I put an IP address on it, I can ping it from windows command line, but GNS3 said that "no connection could be made because the target machine actively refused it."

that shows that the machine exists but that it has no services listening on the specified port, probably there is a firewall stopping the request. disable windows firewall and try again

if this was the reason you can create a rule that this traffic is allowed later on

Okay, so another edit, I got the switches fired up, did some show commands, seems all good, but STP doesn't seem to be present. I hooked 3 IOU switches together and did a sho span and it said there weren't any instances of STP running, what gives?

did you "no shut" the interfaces?
what image did you use?
post a screenshot of your topology

Hmmm, it's not working again, with the error connection actively refused. I turned off firewall and antivirus, still nothing.

I'm assuming it tries to connect to a service on the vm... Is there a way to tell if that service is running? I did a port scan of the VM and the only port open is SSH, so I'm guessing that it can't connect because the port it's trying to reach isn't open.

did you try another IOU L2 image file (some are reportes not working)?
is the content of your license file correct?
what name does your license file have (iourc.txt or .iourc)?
if you restart the vm can you connect again?

Hi martell1000!!!

Is there any feature that do not work in IOU.. as i read in a website that they are not fully working..

which layer 2 technologies have you tried in your labs???

Hi, I dont have a full overview about the features yet, but I am planning to go through the CCNP switch workbook with IOU during the next week. If you guys want I can provide an overview on discorouter.com since there seems to be quiete a demand for gns3 IOU information.

Only thing I can tell you is that I got VLANS, spanning tree, L3 switching and VTP version 1 working, however version 2 gave me some troubles. Heard rumors that ISL trunks are not supportet either but on the faq they say that you can have 90% of the features of a real switch if you use the right image. Seems like we need to do some testing on this...

alan2308

@martell1000 I found your blog through Google not too long after you wrote that post. Keep up the good work!

@Gngogh: I also came across this, which lists whats missing. Not sure how complete it is though.

martell1000 wrote: »

Hi, I dont have a full overview about the features yet, but I am planning to go through the CCNP switch workbook with IOU during the next week. If you guys want I can provide an overview on discorouter.com since there seems to be quiete a demand for gns3 IOU information.

Only thing I can tell you is that I got VLANS, spanning tree, L3 switching and VTP version 1 working, however version 2 gave me some troubles. Heard rumors that ISL trunks are not supportet either but on the faq they say that you can have 90% of the features of a real switch if you use the right image. Seems like we need to do some testing on this...

AS you already did a Tutorial on how to configure IOU in GNS3, I think its a good idea to provide some overview information about GNS3 IOU on your website