I’ve been using Junosphere a lot recently, and it’s a great tool – quick and easy creation of topologies without the need to go to a physical lab to try things out. Takes the guesswork out of a lot of things, which is a real bonus. There are obviously a few things you can’t do in a virtual environment that would be possible in a real one (e.g. QoS, MTU greater than 2000 bytes, MS-MIC in an MX), but it caters for 80% of what you need.
I always thought that it put Juniper leagues ahead of Cisco because you can buy credits to use the system right on the front page. Cisco were late to the party with something called VIRL – Virtual Internet Routing Lab. They were late, but rumour had it that a lot of developers moved from Juniper to Cisco to bring VIRL about. However Junosphere always had the edge for the networking student (as we all remain, whether we are JNCIE or not) because of its accessibility – with VIRL you had to be a Cisco customer and gain access through your account manager. I’ll stick with GNS3 thanks!
That appears to have changed now, and you can get access to VIRL ‘personal edition’ for $199 per year. Now we’re talking. Since it runs on Openstack, you can run up other third-party VMs alongside NXOS, IOS and IOS-XE. Network Inferno has a nice guide on integrating Juniper’s vSRX (formerly Firefly) into VIRL, which looks pretty comprehensive, although I’ve not tried it yet.
I think need to get a copy of this – only problem is it needs me to get a new quad-core laptop with the virtualization extensions in the BIOS to replace my cranky old Lenovo. Ho hum!