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Daniel Joyner
Feb 23, 2014, 2:48:59 PM2/23/14
to geni-...@googlegroups.com
When I setup my topology in Geni, I am using 1 switch with 3 nodes. I am trying to stream video to the switch and have the switch delegate the video to the nodes. My first node I have full traffic being sent through no packet loss, The second node I am setting it up to where every even packet is dropped for example. How can I setup openvswitch to purposefully drop every even packet on node 2?
Thank you,
Daniel Joyner
Niky Riga
Feb 24, 2014, 2:59:27 PM2/24/14
to geni-...@googlegroups.com, Daniel Joyner
Hi,
To the best of my knowledge there is no way for a switch to inspect the packet/byte ID of a packet,
or have the logic of "every other packet", so this has to be done at the controller, i.e. forward all
packets to the controller.
This is fairly inefficient but if the controller runs at the same host as the OVS switch the performance might not be too terrible, you can try it out and see.
You can look for a list of headers that you can match on at the OpenFlow 1.0 spec:
https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.0.0.pdf
If you don't care about being every even, but just dropping some packets you can periodically
install a new flow:
1. install flow 1 that will forward all packets
2. wait for x secs
3. install flow 2 that will drop all packets
4. wait for x secs
5. go back to 1
There are some flags that are described on the spec about how to force a flow to be replaced
by the current flow mod.
You can also always try and modify OVS to do what you want but this is a more involved task.
Depending on what you are trying to do, and how much the performance is important, you might
also want to consider using the click router, which is a software router that gives you more flexibility.
Hope this helps and good luck with your experiment,
Niky
To the best of my knowledge there is no way for a switch to inspect the packet/byte ID of a packet,
or have the logic of "every other packet", so this has to be done at the controller, i.e. forward all
packets to the controller.
This is fairly inefficient but if the controller runs at the same host as the OVS switch the performance might not be too terrible, you can try it out and see.
You can look for a list of headers that you can match on at the OpenFlow 1.0 spec:
https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.0.0.pdf
If you don't care about being every even, but just dropping some packets you can periodically
install a new flow:
1. install flow 1 that will forward all packets
2. wait for x secs
3. install flow 2 that will drop all packets
4. wait for x secs
5. go back to 1
There are some flags that are described on the spec about how to force a flow to be replaced
by the current flow mod.
You can also always try and modify OVS to do what you want but this is a more involved task.
Depending on what you are trying to do, and how much the performance is important, you might
also want to consider using the click router, which is a software router that gives you more flexibility.
Hope this helps and good luck with your experiment,
Niky
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