How is Packet Loss for IP SLA VoIPJitter Operation Calculated?

Hi everyone, I am confused on how the packet loss is calculated in the IP SLA VoIP Jitter Operations. I have a device between 2 routers can can simulate packet loss. When I set the device to 2% packets loss, the 1-way VoIP Jitter operation shows up as 4% packet loss. Please help so I may understand this better.

Thanks.

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Accepted answers

macnugetz

Seashore,

Without seeing exactly how your nodes are interconnected, this sounds like a feasible scenario with IP SLA. The situation you're describing is packet loss from the perspective of A -> B, not from Orion -> A or Orion -> B. IP SLA was designed to be able to assess network quality from perspectives other than where your network monitoring system is deployed, such as the scenario you've described.

Am I missing something? A diagram of your network would help.

-Craig

All comments

RyanJett

Mike,

Here is a Knowledge Base article that outlines how packet loss in IP SLA VoIP Jitter operations is calculated:

http://support.solarwinds.com/kbase/ProblemDetail.cfm?ID=1409

Packet loss is calculated using the following formula.

Packet loss = (SD + DS + MIA) / (SD + DS + MIA + LA + OOS + N)

Where:
SD = rttMonLatestJitterOperPacketLossSD (1.3.6.1.4.1.9.9.42.1.5.2.1.26.<op_num>) DS = rttMonLatestJitterOperPacketLossDS (1.3.6.1.4.1.9.9.42.1.5.2.1.27.<op_num>) OOS = rttMonLatestJitterOperPacketOutOfSequence (1.3.6.1.4.1.9.9.42.1.5.2.1.28.<op_num>) MIA = rttMonLatestJitterOperPacketMIA (1.3.6.1.4.1.9.9.42.1.5.2.1.29.<op_num>) LA = rttMonLatestJitterOperPacketLateArrival (1.3.6.1.4.1.9.9.42.1.5.2.1.30.<op_num>) N = rttMonLatestJitterOperNumOfRTT (1.3.6.1.4.1.9.9.42.1.5.2.1.1.<op_num>) <op_num> = The operation number of your VoIP Jitter operation.

Seashore

I am confused.

A few days ago, VoIP reported high packet loss on link between switch A and B (two seperate sites).
Orion NPM with VoIP is installed on server connected to switch A.
NPM does not show any packetloss on switch B, why?The traffic from the server should go the same way.

How is that possible? I understand by this thread that NPM and VoIP calculates packetloss different.

/Thomas

macnugetz

Seashore,

Am I missing something? A diagram of your network would help.

-Craig

Seashore

This is how it's connected.