How the interface traffic probe calculates the utilization of interfaces.

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Article ID: 37271

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Products

DX Infrastructure Management NIMSOFT PROBES

Issue/Introduction

The interface_traffic probe will query the configured hosts for SNMP data on every predefined interval. Network traffic data will be collected according to a user-setup. The probe may be configured to monitor the network interface (on a PC, UNIX system, router, switch etc.) and report whenever the traffic breaches a predefined threshold.

How to interface traffic probe calculates the utilization of interface.

 

 

The below command and example for calculation of interface_traffic probe

tdiff = (double)curr.sysUptime/100 - (double)cif->previous.sysUptime/100;

Current OutOctet = 715026517864

Previous OutOctet = 712975047817

Difference = 2051470047 (delta value)

Actual delta = 2051470047/tdiff (2051470047/516) = 3975717

maxspeed=1250000

When you create a % of delta (i.e. pctOctet) = (Actual delta *100/ maxspeed)

Calculation is= 3975717*100/1250000=>318.05

As you can see, value is coming more than 100 but we restrict this value to 100% which you can see in your alarm message.

You can verify this calculation through snmpwalk for device IP 192.168.254.31 where interface id is 553 (GigabitEthernet3/1/41)

OIDifDescr= 1.3.6.1.2.1.2.2.1.2. (find GigabitEthernet3/1/41 index, as per log it should be 553)

OIDifHCInOctets= 1.3.6.1.2.1.31.1.1.1.6.553

OIDifHCOutOctets= 1.3.6.1.2.1.31.1.1.1.10.553

OIDifHighSpeed= 1.3.6.1.2.1.31.1.1.1.15.553

OIDifInOctets= 1.3.6.1.2.1.2.2.1.10.553

OIDifOutOctets= 1.3.6.1.2.1.2.2.1.16.553

OIDifSpeed= 1.3.6.1.2.1.2.2.1.5.553

 

 

Environment

CA UIM version 8.2, 8.51
Interface traffic 5.45
 

Resolution


The below command and example for calculation of interface_traffic probe
tdiff = (double)curr.sysUptime/100 - (double)cif->previous.sysUptime/100;
Current OutOctet = 715026517864
Previous OutOctet = 712975047817
Difference = 2051470047 (delta value)
Actual delta = 2051470047/tdiff (2051470047/516) = 3975717
maxspeed=1250000
When you create a % of delta (i.e. pctOctet) = (Actual delta *100/ maxspeed)
Calculation is= 3975717*100/1250000=>318.05
As you can see, value is coming more than 100 but we restrict this value to 100% which you can see in your alarm message.
You can verify this calculation through snmpwalk for device IP 192.168.254.31 where interface id is 553 (GigabitEthernet3/1/41)
OIDifDescr= 1.3.6.1.2.1.2.2.1.2. (find GigabitEthernet3/1/41 index, as per log it should be 553)
OIDifHCInOctets= 1.3.6.1.2.1.31.1.1.1.6.553
OIDifHCOutOctets= 1.3.6.1.2.1.31.1.1.1.10.553
OIDifHighSpeed= 1.3.6.1.2.1.31.1.1.1.15.553
OIDifInOctets= 1.3.6.1.2.1.2.2.1.10.553
OIDifOutOctets= 1.3.6.1.2.1.2.2.1.16.553
OIDifSpeed= 1.3.6.1.2.1.2.2.1.5.553

Additional Information

In addition to monitoring the interface traffic, the probe will monitor error packets, discarded packets, queue length and interface status. It will also report on "dead" lines (no traffic).