To find out how much performance penalty flannel … The network must work in AWS as that is where our initial deployment will be, so it can’t interfere with AWS’ networking. It turns out, other than the ACI nice to have, the three we whittled it down to all cover those if you add the Calico policy model to Flannel. How do you test network performance? Performance. So in this post, I will compare three different setups: Weave with/without fast datapath, and Flannel. To perform the encapsulation, flannel utilizes Universal TAP/TUN devices (in TUN mode) and proxies the IP fragments between the TUN device and a UDP socket. The post also has a network performance test between the two, but doesn’t look at Weave fast datapath.