Changes between Version 41 and Version 42 of GEC16Agenda/OpenFlow/Instructions/Execute


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Timestamp:
03/12/13 01:15:07 (11 years ago)
Author:
nriga@bbn.com
Comment:

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  • GEC16Agenda/OpenFlow/Instructions/Execute

    v41 v42  
    136136}}}
    137137
     138All of the hosts are in the `10.10.1.0/24` subnet. From `host1` try pinging `host2`:
     139{{{
     140ping 10.10.1.2
     141}}}
     142
     143This ping should timeout, since there is no controller running.
     144
    138145== Use a Learning Switch Controller ==
     146We have installed the PoX controller under `/tmp/pox`. On the terminal of the OVS host run:
     147{{{
     148cd /tmp/pox
     149}}}
     150PoX comes with a set of example modules that you can use out of the box. One of the modules is a learning switch. Let's start the controller:
     151{{{
     152./pox.py --verbose forwarding.l2_learning
     153}}}
     154Go back to the terminal of `host1` and try to ping `host2` again:
     155{{{
     156ping 10.10.1.2
     157}}}
     158Now the ping should work.
     159
     160Go back to your OVS host and take a look at the print outs. You should see that your controller installed flows based on the mac addresses of your packets. Kill your controller by pressing `Ctrl-C`. Notice what will happen to your ping.
     161
     162=== Soft vs Hard Timeouts ===
     163All rules on the switch have two different timeouts:
     164  * '''Soft Timeout''': This determines for how long the flow will remain at the forwarding table of the switch, if there no packets received that match the specific flow. As long as packets from that flow are received the flow remains on the flow table.
     165  * '''Hard Timeout''': This determines the total time that a flow will remain at the forwarding table, independent of whether packets that match the flow are received; i.e. the flow will be removed after the hard timeout expires.
     166
     167Can you tell now why there were packets flowing even after you killed your controller?
     168
    139169== Run a port deflection Controller ==
     170In the above example we ran a very simple controller. The power of OpenFlow comes from the fact that you can decide to forward the packet anyway you want based on the supported OpenFlow actions.
     171
    140172== Run a server deflection Controller ==