Hello Luca, > This explains why the figures you see are not 100% accurate. What I could do in ntop is to scale the figures based on sampling rate you specify on the switch, but yet this is not a 100% accurate solution. Yes but at least it correspond nearly to what should be reported even if not 100% accurate and it's easier to explain the results to people that doesn't understand how all the stuff are working.
Gerhard, Luca Deri wrote: > Hi all > I don't think that changing sampling rate to 1 is the solution. sFlow > by its nature is sampled as you will read here: > http://www.sflow.org/about/sampling_theory.php > > This explains why the figures you see are not 100% accurate. What I > could do in ntop is to scale the figures based on sampling rate you > specify on the switch, but yet this is not a 100% accurate solution > > Cheers Luca > > On Nov 3, 2008, at 5:26 PM, jr wrote: > > >> Patrick, >> this is done on the switch, if it supports it. >> My switches (HP ProCurve) won't let me sample any more often than >> every >> 20st packet :/ >> regards, >> johannes >> >> Am Montag, den 03.11.2008, 08:18 -0800 schrieb Patrick Topping: >> >>> Gerhard, >>> >>> I am suffering from the same issue.... Where did you make the change >>> for this --> I've configured the rate to 1 on all ports. >>> >>> Thanks in advance. >>> >>> -Patrick >>> >>> -------------------------- >>> >>> >>> Gerhard Mourani wrote: >>> >>>> Hello Luca, >>>> >>>> >>>>> How did you configure sflow in your foundry? >>>>> >>>> I've configured the rate to 1 on all ports. After doing this, I >>>> can see >>>> that captured informations are better accurate but not 100%. For >>>> example, if I transfers 100 MB now, I will see around 90 MB. I >>>> think I >>>> cannot do better than that because it use sampling as you said. >>>> >>>> Gerhard, >>>> >>>> Luca Deri wrote: >>>> >>>> >>>>> Gerhard >>>>> sflow uses sampling. hence if you send let's say 100 you will see 1 >>>>> using sflow. How did you configure sflow in your foundry? >>>>> >>>>> Luca >>>>> >>>>> On Oct 31, 2008, at 7:33 PM, Gerhard Mourani wrote: >>>>> >>>>> >>>>> >>>>> >>>>>> Hello List, >>>>>> >>>>>> I've activated the sFlow plugin into my ntop version 3.3.8 to >>>>>> capture >>>>>> and display sFlow data coming from my "Foundry Network FastIron >>>>>> Edge >>>>>> 9604" model. If I check inside the plugin page of sFlow about >>>>>> 'sFlow >>>>>> Interface Statistics' everything are correct and reported data >>>>>> transfers >>>>>> for 'Administrative' or 'Operational' status are ok. But now my >>>>>> problem >>>>>> is when I check inside the ntop web interface and especially about >>>>>> collected data, here the problem is that returned informations >>>>>> about >>>>>> amount of data are wrong, I mean the amount of data doesn't >>>>>> correspond >>>>>> to what have really been transfered. So for example if I >>>>>> transfer 135 >>>>>> MBytes I can only see 295.0 KBytes in ntop. Someone know how to >>>>>> fix >>>>>> this? >>>>>> >>>>>> Thanks for your helps, >>>>>> Gerhard, >>>>>> _______________________________________________ >>>>>> Ntop mailing list >>>>>> Ntop@unipi.it >>>>>> http://listgateway.unipi.it/mailman/listinfo/ntop >>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> Ntop mailing list >>>>> Ntop@unipi.it >>>>> http://listgateway.unipi.it/mailman/listinfo/ntop >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> Ntop mailing list >>>> Ntop@unipi.it >>>> http://listgateway.unipi.it/mailman/listinfo/ntop >>>> >>>> >>>> >>>> >>> _______________________________________________ >>> Ntop mailing list >>> Ntop@unipi.it >>> http://listgateway.unipi.it/mailman/listinfo/ntop >>> >> _______________________________________________ >> Ntop mailing list >> Ntop@unipi.it >> http://listgateway.unipi.it/mailman/listinfo/ntop >> > > _______________________________________________ > Ntop mailing list > Ntop@unipi.it > http://listgateway.unipi.it/mailman/listinfo/ntop > _______________________________________________ Ntop mailing list Ntop@unipi.it http://listgateway.unipi.it/mailman/listinfo/ntop
