Mini Net Setup Notes

process

• download mininet vm image
• install virtual box
• import image
• change keyboard layout to german
• create host-only network adapter for ssh into vm
• setup according to https://github.com/mininet/openflow-tutorial/wiki/VirtualBox-specific-Instructions
• grabbed ip for adapter and added it to /etc/network/interfaces file
• install Xming Server (windows)/Xquartz Mac
• default xauth cookies wouldn't work, so created own xauth files (https://unix.stackexchange.com/questions/412065/ssh-connection-x11-connection-rejected-because-of-wrong-authentication)
• refreshing the ssh session causes root user to loose xauth cookie, created script to automatically add current display and xauth cookie to root user cookies (mininet requires user to be root)

example mininet topology

• use LinuxRouter class with IP forwarding to simulate routers
• created minimalistic network (simplenetwork.py) with only 2 routers, 2 switches and 2 hosts
• switches are unnecessary as we only connect 1 host per router, but might become relevant in the future when adding multiple hosts
• added simple_extendednetwork.py containing 3 hosts and 3 routers

errors

• x11 wrong authentication when opening xterm in mininet console (https://stackoverflow.com/questions/67319171/x11-connection-rejected-because-of-wrong-authentication-in-mininet)

IP Routing and FRR

General setup

• created example from Short-Cut Paper
• added static ip routing for hosts and routers
• fast rerouting requires routing by inport, using ip policies and ip rules in linux kernel
• ip policies allow requests from specific ethernet interfaces to use a specific routing table
• routing tables would then include specific frr routes, e.g. if a packet going to R4 would be received on the port connected to R2 on R1

IP Route configuration

• created python dictionaries that have entries for each router and for each routing table
• routing tables consist of the default table for all requests from connected host and router itself and a table for each additional network interface, reacting on incoming packets for fast rerouting
• "from" keyword in ip rules could be used to differentiate between returning packets and "normally" routed packets

Testing suite

• implemented simple testing suite that is able to create tests by definition

failure scenarios

• 2 types of failure scheduling: intermediate and concurrent
• intermediate: a certain test operation is performed (like pings), a failure is induced, and the same test is performed again
• concurrent: a timer is started and the test is run, timer should act while the test is running and performs the failure on runtime

failure types

• interface shutdown: an interface is deactivated by calling "ifconfig {interface} down" to simulate a broken link

General information

networks to look out for

• mesh ()
• ring/double ring (clock- and counterclockwise)

openflow learning

installation

• start controller on port 6633, change port in protocol configuration of wireshark from 6653 to 6633

wireshark filter for displaying openflow packets

openflow_v1 and not (openflow_1_0.type == 2 or openflow_1_0.type == 3)

Technologies

Mininet

A tool for creating virtual networks. Is able to emulate hosts, switches, routers, hubs etc. It uses Openflow to realise many of these emulations.

Openflow

A tool used to create virtual switches etc. Can be connected to a controller (e.g. created with POX) to write custom flow handling.

POX

A python library to create a controller for handling flow of switches etc.

Questions

Current state

• implementing local FRR in test routers -> policy routing (performance?)
• implementing short cut
• using "ifconfig {if} down" for failing link simulation

Resources

• Performance measuring and failure scenarios (https://www.researchgate.net/publication/271472089_Simulation_in_an_SDN_network_scenario_using_the_POX_Controller)
• General information on IP Routing and IP FRR https://support.huawei.com/enterprise/en/doc/EDOC1100086956#EN-US_TOPIC_0291822208
• Inport aware routing https://ieeexplore.ieee.org/abstract/document/6848098?casa_token=YvHY-ya08KYAAAAA:GUDm0MRR4AUzu3XSktfJOSIJFxzFgBjafakNHM62BeQJp9aM_O9kXrkaPfvSbyTbo-Mzyvyf
• policy routing rules https://blog.scottlowe.org/2013/05/29/a-quick-introduction-to-linux-policy-routing/

Tasks

• end of february -> write "Basics" section

Tools

• Mininet visualizer: http://demo.spear.narmox.com/app/?apiurl=demo#!/mininet