Thursday, March 29, 2018

Mininet weathermap

Mininet dashboard is a real-time dashboard displaying traffic information from Mininet virtual networks. The screen capture demonstrates the real-time network weather map capability that was recently added to the dashboard. The torus topology is displayed and link widths are updated every second to reflect traffic. In this example a large flow between switches s1x1 and s3x3 is routed via s1x3.

The network was created using the following Mininet command:
sudo mn --custom=sflow-rt/extras/sflow.py --link tc,bw=10 \
--topo torus,3,3 --switch ovsbr,stp=1 --test iperf
In the screen capture above you can clearly see the large flow traversing switches, s4, s3, s2, s1, s9, s13, and s15 in a tree topology. The network was created using the following command:
sudo mn --custom sflow-rt/extras/sflow.py --link tc,bw=10 \
--topo tree,depth=4,fanout=2 --test iperf
The screen capture above shows a large flow traversing switches s1, s2, s3, and s4 in a linear topology. The network was created using the following command:
sudo mn --custom sflow-rt/extras/sflow.py --link tc,bw=10 \
--topo linear,4 --test iperf
It's also easy to create Custom Topologies. The following command creates the example custom topology, topo-2sw-2host.py, that ships with Mininet:
sudo mn --custom ~/mininet/custom/topo-2sw-2host.py,sflow-rt/extras/sflow.py \
--link tc,bw=10 --topo mytopo --test iperf
The final screen capture shows all three tests, identifying top flows, busiest switch ports, and showing the diameter of the network topology. This test run demonstrates the efficiency of using Mininet; creating, testing, and destroying three virtual networks, toroid (9 switches, 9 hosts, 27 links), tree (15 switches, 16 hosts, 30 links), linear (4 switches, 4 hosts, 7 links), in a few minutes, on a laptop.

For anyone curious about the technologies underpinning these examples, Mininet is a Python program that uses Open vSwitch to connect lightweight Linux containers representing hosts and switches. Open vSwitch includes industry standard sFlow instrumentation that efficiently streams telemetry to sFlow-RT real-time analytics software running the mininet-dashboard application. Mininet-dashboard uses the vis.js library to create the dynamic network diagrams.

Mininet's support of sFlow provides the same measurement technology used in physical switches, from low cost edge switches to high end chassis routers, including: A10, Aerohive, ALUe, Allied Telesis, Arista, Aruba, Big Switch, Cisco, Cumulus, Dell, D-Link, Edge-Core, Extreme, F5, Fortinet, Huawei, IP Infusion, Juniper, Netgear, OpenSwitch, Pica8, Proxim, Quanta, SMC, ZTE, and ZyXEL. A common measurement protocol makes it easy to move between emulated and physical networks, for example, Large flow detection describes how to scale sFlow configuration settings from emulated 10Mbit/s Mininet networks to 10G, 40G and 100G physical networks, and SC16 live real-time weathermaps uses the technologies described in this article to monitor a large 100Gbit/s network.

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