OpenFlow Accuracy Measurement Tool Suite

This collection of tools can be used to assess certain statistics obtainable from OpenFlow devices. All tools are based on input/output compatible with the Open vSwitch tools, and ovs-ofctl in particular.

Trace generator

Produces a pcap file, a .flows file (to be fed to ovs-ofctl add-flows using stdin) and a .truth file. The latter is used as input for the Validator script (see below)

usage: tracegen.py [-h] [-t] [-4 | --v6flowlabels] [-i] [-m M] -n N
                   [--table TABLE] [--actions ACTIONS]
                   [--idle-timeout IDLE_TIMEOUT] [--hard-timeout HARD_TIMEOUT]
                   [--vlan VLAN] -o OUTFILE

optional arguments:
  -h, --help            show this help message and exit
  -t, --tcp             Create TCP as L4, default is UDP
  -4, --ipv4            Create IPv4 as L3, default is IPv6
  --v6flowlabels        Create flows based on IPv6 Flow Labels
  -i, --icmp            Create ICMPv6 or ICMPv4
  -m M                  Max number of packets per flow, default 1000
  -n N                  Number of flows to create
  --table TABLE         OpenFlow switch table for the flow entries TODO
                        implement this
  --actions ACTIONS     Define 'actions' attribute for OpenFlow flows. Default
                        'output:2'
  --idle-timeout IDLE_TIMEOUT
                        Set IDLE_TIMEOUT, default 0. Will set send_flow_rem.
  --hard-timeout HARD_TIMEOUT
                        Set HARD_TIMEOUT, default 0. Will set send_flow_rem.
  --vlan VLAN           Set dl_vlan
  -o OUTFILE, --outfile OUTFILE
                        PCAP output file

Validator

Reports on the accuracy of gathered OpenFlow measurements (-m) compared to the ground-truth (-t). In our experience, most devices add bytes per packet to the byte counter for every flow entry (often, 4 bytes per packet). Use -b to correct for this, or all flows entries will be reported inaccurate.

usage: validate.py [-h] -t TRUTHFILE -m MEASUREDFILE [-b BYTE_DELTA] [-v]

optional arguments:
  -h, --help            show this help message and exit
  -t TRUTHFILE, --truthfile TRUTHFILE
                        Ground truth in ovs-ofctl flow format (output of
                        packetgen.py)
  -m MEASUREDFILE, --measuredfile MEASUREDFILE
                        Measurements in ovs-ofctl dump-flows format
  -b BYTE_DELTA, --byte-delta BYTE_DELTA
                        Possible byte delta per packet, used if switches add
                        bytes consistently for some reason
  -v, --verbose         Be verbose

Duration variance

Lastly, there is a script taking ovs-ofctl dump-flows as its input format. It groups flow entries based on their cookie values, and calculates statistical info on the duration of these flow entries. More information is in the script itself.