GNS3 vs iPerf2

GNS3 is free, open-source software for emulating, configuring, testing, and troubleshooting virtual and real networks. Its graphical client works with a virtual machine, and servers can run locally or remotely. Users can combine emulated devices running actual images with simulated devices, including a built-in layer 2 switch. It supports appliances from vendors such as Cisco, Brocade, Cumulus Linux, and HPE, as well as Docker, QEMU-based appliances, VMware, VirtualBox, Hyper-V, and connections to real networks. The GNS3 Marketplace offers preconfigured appliance templates with recommended settings. It runs on Windows, macOS, and Linux; documentation recommends the GNS3 VM for most Windows and macOS setups and complex topologies. Users must supply their own Cisco IOS images. There are no monthly or yearly license fees, and device capacity depends in practice on the host computer’s CPU and memory. GNS3 is used for networking education, certification practice, proofs of concept, demonstrations, and interoperability testing. A server has no authentication enabled by default and should be restricted at the network level.

iPerf2 measures network traffic performance, including throughput, latency, link capacity, and responsiveness. Testing uses a client to send traffic to a server. It can generate TCP and UDP traffic in one-way, bidirectional, full-duplex, and simultaneous multi-stream configurations. Measurements include one-way delay, round-trip time, jitter, packet loss, and throughput. It supports IPv4, IPv6, and multicast, including source-specific multicast joins, and reports can include enhanced metrics or use CSV format. The project manual describes an Android client with live meters for throughput, latency, and congestion signals. The manual also describes permit-key HMAC authentication using a timestamped HMAC-SHA256 value, with replay limited by a configurable time window. Its Professional feature set includes server access gating and remotely enabled server-side latency histograms. Measurements happen at socket-level reads and writes, so lower-level protocol-header overhead is excluded. iPerf2 and iPerf3 are separate implementations and do not interoperate. It runs on Android, Linux, macOS, and Windows, and can be self-hosted. Both listed editions are free.