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Oktopus

Walkthrough Tutorial

This page guide you to start working with Oktopus.

We will create a simple video on demand (VoD) SDN application. The objective of the application is to send the video through the network with the minimal cost. For simplicity, we will request just one multicast session. For the multicast session, we would like it to go through a firewall and then to a video transcoder.

Setup

In this tutorial, we will be using a docker container pre-install with all the necessarily dependencies. So before following this walkthrough, make sure to have docker setup on your system. Afterward, retrieve the following Oktopus docker and example repository:

  • Git repository containing the example files:
      git clone https://github.com/Oktopus-Multicast/oktopus_example.git
  • Oktopus Docker:
      docker pull charlee593/oktopus

Creating an VoD SDN Application

  1. Start with creating an application object and initializing the application with the Abilene network topology.
     app = App(name='Abilene', topo='Abilene_resources.graphml')
  2. Create and deploy a firewall network function on the network node 2 and a video transcoder network function on the network node 9.
     firewall = Service(name='fw', ordered=True, resources_cap={'cpu': 10})
 video_transcoder = Service(name='vt', ordered=True, resources_cap={'cpu': 10})

 app.get_node(2).add_service(firewall)
 app.get_node(9).add_service(video_transcoder)

  3. Create a multicast session, where the source is node 1 and the destinations are node 8, 2, 7 and 9. It demands 10 Mbps bandwidth. It requires to traverse a firewall and a video transcoder in order.

     session = Session(addr='192.0.2.0', 
                 src=1, 
                 dsts={8, 2, 7, 9}, 
                 bw=10000000, 
                 t_class='vod',
                 res={'fw':{'cpu': 10}, 'vt':{'cpu': 10}},
                 required_services=['fw', 'vt']
                 )

 app.add_sessions([session])

  4. Specify the algorithm to minimize the routing cost. Also, lets limit number of video trancoding tasks to further reduce the cost.

     routing = Routing()
 routing.add_objective(name='minroutingcost')

 routing.add_node_constraint(node=app.get_node(9), srv=video_transcoder, name='cpu', value=5)

 app.set_routes(routing)

  5. Produce the solution.

     app.solve()

The application should look like this:

from oktopus import App, Routing, Session, Service

# Application API
app = App(name='Abilene', topo='Abilene_resources.graphml') # Load the network topology

firewall = Service(name='fw', ordered=True, resources_cap={'cpu': 10})
video_transcoder = Service(name='vt', ordered=True, resources_cap={'cpu': 10})
app.get_node(2).add_service(firewall) # add firewall network function to node 2
app.get_node(9).add_service(video_transcoder) # add video transcoder network function to node 9

# Session API
session = Session(addr='192.0.2.0', 
                  src=1, 
                  dsts={8, 2, 7, 9}, 
                  bw=10000000, 
                  t_class='vod',
                  res={'fw':{'cpu': 10}, 'vt':{'cpu': 10}},
                  required_services=['fw', 'vt'] # set service chain
                )

app.add_sessions([session]) # add multicast session


# Routing API
routing = Routing()
routing.add_objective(name='minroutingcost')

routing.add_node_constraint(node=app.get_node(9), srv=video_transcoder, name='cpu', value=5) # limit firewall usage to 5 cpu

app.set_routes(routing)

# Produces a solution
app.solve()

To run the application, use the provided docker.

docker run --rm -it -v="$PWD:/home" charlee593/oktopus python example.py

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