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sFlow catch every packet?




we want to generate Statistics about our Network Traffic. To do this we want to use sFlow. Now our question is if sFlow catches every Packet send over an Port or if the measured Data only show the value for the moment when PRTG query the switch. We use a HP ProCurve 2810 with following sFlow Configuration:

Port  | Sampling                 Dropped    | Polling
       | Enabled  Rate     Header Samples    | Enabled Interval
 ----- + -------  -------- ------ ---------- + ------- --------
 1       Yes      50       128    2133356842   No      0
 2       Yes      50       128    2381792      No      0
 3       Yes      50       128    11013691     No      0

Is this enough to catch all Data, or do we need to enable Polling. If we need to activate Polling which Interval should we use? Can i be sure to get information about packets which are send between 2 PRTG querys?

Hope to get help soon. Thanks!

2810 procurve sflow

Created on Mar 12, 2014 12:44:23 PM

Last change on Mar 13, 2014 10:08:59 AM by  Torsten Lindner [Paessler Support]

3 Replies




thank you very much for your KB-Post. Sflow (like the other Flow-Based traffic monitoring sensors) are more "Push"-based. So your device is sending flow-information all the time to PRTG. PRTG will then account everything that is sent in the flow-packets. Please bear in mind that 'Sampling' is often used with Sflow (this is set on the sending device), if Sampling is used, PRTG cannot see each traffic, because the device is only selecting every 100th (for example) packet to be forwarded to PRTG.

best regards.

Created on Mar 13, 2014 10:11:12 AM by  Torsten Lindner [Paessler Support]



Hello, thank you for your reply. If i understanding this right, i need to disable sampling and only enable polling with a rate of 60. Is this correct?

Created on Mar 13, 2014 3:14:50 PM



The scanning interval is not that important with Flow & Sniffing sensors, because the sensor looks at all data, not only at the set points every 60 seconds.

Created on Mar 13, 2014 4:53:25 PM by  Torsten Lindner [Paessler Support]

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