With docker container support in 1.5 we can now add more and more appliances. The first appliance, Chromium, is a a great demo on how light a container is in your topologies even a web browser. ntopng of the web console support of GNS3, with some internal magic the console for the ntopng appliance is not a telnet or a VNC but the webinterface of ntopng in your browser and this without network config.
Starting with GNS3 1.5 and the docker container support it's now easy to use an OVS in your topologies.
Open vSwitch is a production quality, multilayer virtual switch licensed under the open source Apache 2.0 license. It is designed to enable massive network automation through programmatic extension, while still supporting standard management interfaces and protocols (e.g. NetFlow, sFlow, IPFIX, RSPAN, CLI, LACP, 802.1ag). In addition, it is designed to support distribution across multiple physical servers similar to VMware's vNetwork distributed vswitch or Cisco's Nexus 1000V.
ntopng is the next generation version of the original ntop, a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntopng is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform, MacOSX and on Windows as well. ntopng users can use a a web browser to navigate through ntop (that acts as a web server) traffic information and get a dump of the network status. In the latter case, ntopng can be seen as a simple RMON-like agent with an embedded web interface.