Dpctl Documentation

Dpctl is a management utility that enable some control over the OpenFlow switch. With this tool it's possible to add flows to the flow table, query for switch features and status, and change other configurations.

A dpctl command has the following syntax

dpctl [OPTIONS] SWITCH COMMAND [ARG...]

Connection methods

The SWITCH argument should use one of the following active OpenFlow connection methods:

 tcp:HOST[:PORT]         PORT (default: 6633) on remote TCP HOST
 unix:FILE               Unix domain socket named FILE
 fd:N                    File descriptor N

Dpctl Commands

dpctl -h 

The command above shows the available dpctl but some doubts may appear on how to use some of them. So lets's have a closer look at all commands with usage examples.

Features

Dpctl sends a features request message to the switch, which answers with a features reply.

Usage Example

dpctl unix:/var/run/s1.sock features 

The reply message should look like this.

feat_repl{dpid="0x000002d5e8cde975", buffs="256", tabs="64", aux_id="0", caps="0x4f"]}

Where dpid is the datapath identification, buffs is the number of packets the switch can buffer, tabs is the number of flow_tables, aux_id refers to the auxiliary connection id and caps is the value of the switch capabilities bitmask.

Get-config and set-config

Dpctl can query and set switch configuration parameters.

Usage Example

We will query for the switch configuration. You should see the default values for the configuration flags and the maximum number of bytes of a packet, mlen, that the switch can send to the controller.

dpctl unix:/var/run/s1.sock get-config 
SENDING:
conf_req

RECEIVED:
conf_repl{conf={flags="0x0", mlen="128"}}

Now we will set the switch configuration flags to 1, which means drop fragments, and increase the packet limit of bytes to send to the controller.

dpctl unix:/var/run/s1.sock set-config flags=0x1,miss=512
SENDING:
set_conf{conf={flags="0x1", mlen="512"}}

OK.

Now we query again to check the changes

dpctl unix:/var/run/s1.sock get-config
SENDING:
conf_req

RECEIVED:
conf_repl{conf={flags="0x1", mlen="512"}}

Status description

Query description of switch hardware and software, where mfr is the manufacturer description, hw is the hardware description, sw is the software description, sn is the serial number and, dp refers to the datapath description.

Usage Example

dpctl unix:/var/run/s1.sock
SENDING:
stat_req{type="desc", flags="0x0"}

RECEIVED:
stat_repl{type="desc", flags="0x0", mfr="Stanford University, Ericsson Research and CPqD Research",
hw="OpenFlow 1.3 Reference Userspace Switch", sw="Dec 14 2012 09:52:06", sn="1", dp="OpenFlow 1.3  
Reference Userspace Switch Datapath"}

Table status and table configuration

table-mod stats-table

Group

stats-group group-mod stats-group-desc

Meter

meter-config stats-meter meter-mod

Port

stats-port port-mod

Queue

queue-get-config stats-queue

Flow

stats-flow stats-aggr flow-mod

Options

There are a few number of options to be passed to dpctl, which can be used for purposes of information, increase the switch verbosity level and change default command behaviors.

Logging options

-v, --verbose=MODULE[:FACILITY[:LEVEL]]  set logging levels 
-v, --verbose           set maximum verbosity level
--log-file[=FILE]       enable logging to specified FILE
                      (default: /usr/local/var/log/openflow/dpctl.log)

Other options

--strict                    use strict match for flow commands
-t, --timeout=SECS          give up after SECS seconds
-h, --help                  display this help message
-V, --version               display version information