[ovs-dev] Modification in ovs-ofctl commands for implementation of Importance parameter.

[Shashwat Srivastava]

Hi Team,

We are working on the implementation on eviction mechanism on basis of 
importance as per openflow specs-1.4. We have added importance parameter 
in the flow entry.

Following is our understanding for Delete Flow mechanism:
We have studied the code and have found that OFPFC_DELETE_STRICT specifies 
only two fields on which flow is deleted which are OUT_PORT & PRIORITY 
i.e. flows are deleted only on the basis of out_port and priority 
specified in the del-flows command. Please confirm whether there will be 
any change in "ovs-ofctl del-flows [--strict] ..... " command by 
specifying importance in it as it is not specified anywhere in specs that 
deletion of flows should be done on basis of importance and its 
significance is only to evict flows. 

Following is our understanding for Mod Flow mechanism:
For "ovs-ofctl mod-flows ... " we think that their will be no change with 
respect to "importance". Openflow-specs 1.4 specifies on page 36 that in 
both cases (with strict and without strict) their will be change only in 
instructions field. Fields of hard_timeout, idle_timeout, cookies, flags 
and counters & also priority remains unchanged. 
Also when we were trying to modify the flows, we were able to change the 
cookie value and action using the mod-flows command. Whereas we were not 
able to modify flow for priority or timeout.

Query : As per our understanding of code and open flow specs 1.4 we think 
that, mod-flows..... & del-flows.... command will not change after 
implementation of importance field in the flow, as significance of 
IMPORTANCE field is only for eviction mechanism. Kindly confirm the same.


Regards
Shashwat Srivastava
Mailto: shashwat.srivastava at tcs.com
Website: http://www.tcs.com
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