Additionally if you see the Specification requirement for the EXT-335 :
Instruction: Stat-Trigger stat thresholds: Generate an event to the
controller if some of the flow statistics cross one of the stat threshold
values.
Which is what is the part which we wanted to check from the Unit test case
in ryu supporting this feature.
We agree with you that the OFPStats compose the values w.r.t the below
parameters but it is equally important to understand that if controller is
looking for the Extensible statistics (unlike the one which is done in
OXM) so does that mean switch will internally compare these values from
the stats and trigger an EVENT to encode or prepare an OXS message format
after every X times the request is received (as part of the FLOW_MOD) from
the controller . What are your thoughts for the same?
Argument
Value
Description
duration
Integer 32bit*2
Time flow entry has been alive. This field is a tuple of two Integer
32bit. The first value is duration_sec and the second is duration_nsec.
idle_time
Integer 32bit*2
Time flow entry has been idle.
flow_count
Integer 32bit
Number of aggregated flow entries.
packet_count
Integer 64bit
Number of packets matched by a flow entry.
byte_count
Integer 64bit
Number of bytes matched by a flow entry.
Thanks & Regards
Poonam Ghosh
Technical Architect
TCS
From: Poonam Ghosh/BLR/TCS
To: Ryu-devel <ryu-devel@lists.sourceforge.net>, Iwase Yusuke
<iwase.yusu...@gmail.com>
Date: 09/22/2016 11:50 PM
Subject: Re: [Ryu-devel] Query regarding the Statistics Trigger
Instruction -- OFPInstructionStatTrigger
First of all thanks Iwase for your reply to this thread.
Yes, currently we do not have a functional code which supports all the
features supporting the OF version 1.5.
And that is the reason we are planning to implement the EXT features to
support the handling of Flow statistics for flexible encoding fro Egress
tables which is currently not been supported.
I have gone through the OFV1.5 Specification for EXT-334 and EXT-335 and
started with prototyping the features requirement code and will share with
you once the patch with the EXT-335 is available.
The idea is to test the RYU controller with the EXT-335 switch
functionality so that it becomes easy to validate the requirement and to
check how the statistics is responded to the controller.
The below query was to understand on the bitmap flags and how are the
thresholds been calculated to decide on the setting of the bitmap flags
and under what conditions the OXS stats are responded as part of the FLOW
STATS REPLY (for the corresponding FLOW_MOD).
Primarily i will keep this thread of technical discussion Open for
discussing the RYU v1.5 changes and how can we leverage the controller
behavior to be tested with the switch functionality.
Thanks & Regards,
Poonam Ghosh
Technical Architect,TCS
From: Iwase Yusuke <iwase.yusu...@gmail.com>
To: poonam.gh...@tcs.com
Cc: ryu-devel@lists.sourceforge.net
Date: 09/22/2016 06:07 AM
Subject: Re: [Ryu-devel] Query regarding the Statistics Trigger
Instruction -- OFPInstructionStatTrigger
Hi,
On 2016年09月22日 17:08, Poonam Ghosh wrote:
> Hello,
>
> We have been referring the RYU source code to understand the OF Specific
instructions primarily OFV1.1, OFV1.2, OFV1.3,OFV1.4 and OFV1.5.
> Currently while simulating the tests with Instruction
OFPIT_STAT_TRIGGER(Specification EXT-335) we got couple of Open points to
understand more on the implementation part which needs more clarity to
understand.
>
> As part of the Specification details for the EXT-335 we understand that
"This Instruction is primarily required to send out Openflow Extensible
stats (as part of flexible encoding) to Controller based on certain
thresholds which are user defined". Please correct my understanding for
the same?
>
> So this is how the Instruction looks with the bitmap Flags shown below:
>
> enum ofp_stat_trigger_flags {
> OFPSTF_PERIODIC = 1 << 0, /* Trigger for all multiples of thresholds.
*/
> OFPSTF_ONLY_FIRST = 1 << 1, /* Trigger on only first reach threshold. */
> };
> /* Instruction structure for OFPIT_STAT_TRIGGER */
> struct ofp_instruction_stat_trigger {
> uint16_t type; /* *OFPIT_STAT_TRIGGER* */
> uint16_t len;
> uint32_t flags;
> struct ofp_stats thresholds;
> };
> OFP_ASSERT(sizeof(struct ofp_instruction_stat_trigger) == 16);
>
> Based on the above understanding and the current RYU implementation it
is unclear of how the Flags and thresholds are derived and based on what?
> Because if we really see the RYU python scripts for VERSION1.5 we see
the hardcoded values for duration, idle_time , flow_count, packet_count,
and byte_count as part of the OXS fields filling.
What do you exactly mean "hardcoded"?
"OFPStats" class can compose the arbitrary flow stats fields which are
defined in OpneFlow 1.5.
And the API is similar to OFPMatch.
http://ryu.readthedocs.io/en/latest/ofproto_v1_5_ref.html#ryu.ofproto.ofproto_v1_5_parser.OFPStats
> For our understanding we are not clear on how can we decide on the above
Fields of when the Instruction trigger needs to set the*PERIODIC FLAG* or
*ONLY_FIRST* flag as part of the FLOW_STATS REPLY To controller.
For example, if you want to send the OFPIT_STAT_TRIGGER instruction with
the PERIODIC flag and
packet_count=100 in the stats field:
instructions = [
parser.OFPInstructionStatTrigger(
flags=ofproto.OFPSTF_PERIODIC,
thresholds=parser.OFPStats(packet_count=100),
)
]
BTW, unfortunately we haven't found the switch implementation which fully
supports OpenFlow 1.5
including EXT-335.
Do you know or have any implementation for supporting OpenFlow 1.5?
Thanks,
Iwase
>
> Much appreciate your response for the same.
>
> Thanks & Regards
> Poonam Ghosh
> Technical Architect, TCS
>
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