I have an upcoming configuration change that involves a fairly complex BGP implementation. I’ll be setting up BGP between two Avaya ERS 8600s, two Cisco Nexus 7010s and two Cisco 3845 routers. A few months back I started looking at setting up a few physical routers in the lab to work through the actual Cisco configuration. That’s when I stumbled upon GNS3, Dynamips, Dynagen and Qemu.

Needless to say I never made it to the lab. I did have a few issues getting GNS3 going but those could probably be attributed to PICNIC (problem in chair not in computer). I also had some difficulties getting GNS3 to save all the router configurations, again probably a shortcoming of not reading all the documentation.

I’m

really impressed… while it can’t emulate any of the switches it does a great job of emulating the basic router hardware. The image you use in GNS3 is the actual IOS image that you download from Cisco’s website.

I’ll definitely be adding GNS3 to my list of recommended tools!

Cheers!