CA Spectrum interface threshold alarm showing values greater than 100%

Document ID : KB000056497
Last Modified Date : 14/02/2018
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Description:

A CA Spectrum interface threshold alarm shows values greater than 100%. The following is an example:

Critical Sep 4, 2014 1:22:37 PM EDT Device_wan0_0 Threshold Exceeded for IN LOAD for an unacceptable duration. The threshold value is 70 %, and the current value is 22891 %. Model Type = Gen_IF_Port, Name = Device_wan0_0. 0x1133b

Check to see if there are associated 0x10d80 events are similar to the following:

Sep 4, 2014 6:51:16 AM EDT Device_wan0_0 Problem detected with data in the Interface Performance Calculations

SOURCE DATA ************************************

Initial X_IN_OCTETS: 234538471403
Final X_IN_OCTETS: 234538475706

Initial X_OUT_OCTETS: 106579090705
Final X_OUT_OCTETS: 106579095716

Initial X_IN_ERROR_PKTS: 0
Final X_IN_ERROR_PKTS: 0

Initial X_OUT_ERROR_PKTS: 0
Final X_OUT_ERROR_PKTS: 0

Initial X_IN_NO_RESOURCE_PKTS: 0
Final X_IN_NO_RESOURCE_PKTS: 0

Initial X_OUT_NO_RESOURCE_PKTS: 0
Final X_OUT_NO_RESOURCE_PKTS: 0

Initial X_IN_NUCAST_PKTS: 0
Final X_IN_NUCAST_PKTS: 0

Initial X_OUT_NUCAST_PKTS: 0
Final X_OUT_NUCAST_PKTS: 0

Initial X_IN_MCAST_PKTS: 2963948
Final X_IN_MCAST_PKTS: 2963949

Initial X_OUT_MCAST_PKTS: 0
Final X_OUT_MCAST_PKTS: 0

Initial X_IN_BCAST_PKTS: 0
Final X_IN_BCAST_PKTS: 0

Initial X_OUT_BCAST_PKTS: 0
Final X_OUT_BCAST_PKTS: 0

Initial X_IN_UCAST_PKTS: 395133432155898
Final X_IN_UCAST_PKTS: 395137727123232

Initial X_OUT_UCAST_PKTS: 642049395
Final X_OUT_UCAST_PKTS: 642049435

Initial X_IN_UNKNOWN_PROTOS: 0
Final X_IN_UNKNOWN_PROTOS: 0

Initial X_SYSTEM_UP_TIME: 2415725744
Final X_SYSTEM_UP_TIME: 2415726786
Delta SYSTEM_UP_TIME: 1042

PREVIOUS IFTYPE: 6
CURRENT IFTYPE: 6

PREVIOUS X_LOW_BANDWIDTH: 10000000
CURRENT X_LOW_BANDWIDTH: 10000000

PREVIOUS X_HIGH_BANDWIDTH: 10
CURRENT X_HIGH_BANDWIDTH: 10


CALCULATED METRICS ***************************************

PREVIOUS BIT_RATE_IN: 2824
PREVIOUS BIT_RATE_OUT: 2982

CURRENT BIT_RATE_IN: 3303
CURRENT BIT_RATE_OUT: 3847


PREVIOUS LOAD_TOTAL: 0
PREVIOUS LOAD_IN: 0
PREVIOUS LOAD_OUT: 0

CURRENT LOAD_TOTAL: 659495
CURRENT LOAD_IN: 659495
CURRENT LOAD_OUT: 0


PREVIOUS IN_THROUGHPUT_PKTS: 3
PREVIOUS OUT_THROUGHPUT_PKTS: 3
PREVIOUS TOTAL_THROUGHPUT_PKTS: 6

CURRENT IN_THROUGHPUT_PKTS: 412184964
CURRENT OUT_THROUGHPUT_PKTS: 3
CURRENT TOTAL_THROUGHPUT_PKTS: 412184967


PREVIOUS PERCENT_ERROR_PKTS: 0
CURRENT PERCENT_ERROR_PKTS: 0


PREVIOUS PERCENT_DISCARDED_PKTS: 0
CURRENT PERCENT_DISCARDED_PKTS: 0




INTERNAL SOURCES ATTRIBUTES ******************************

0x12db6
0x12db2
0x12db4
0x12db8
0x12db7
0x12db3
0x12db5
0x130d1
0x12dfa
0x12db0
0x12dae
0x12daa
0x12dac
0x12db1
0x12daf
0x12dab
0x12dad
0x12bb5
0x12bb4
0x220177
0x12df9

EXTERNAL SOURCES ATTRIBUTES:

0x11317
0x11318
0x11319
0x1131a
0x1131e
0x1131f
0x11321
0x11348
0x1134c
0x11f63
0x11f64
0x11f65
0x11f66
0x11f67
0x11f68
0x11f69
0x11f6a
0x11f6b
0x22001a
0x22001a
0x22005e
0x10d80

The 0x10d80 event basically shows the user what data was used to compute load, load in and load out. Out of the box, when CA Spectrum initially models a device, CA Spectrum tests which counters (32 and 64 bit) a ports supports. It also checks when the model is reconfigured and once every 24 hours. If a port supports a 64 bit counter, CA Spectrum will use the 64 bit counter when computing load, load in and load out.

CA Spectrum uses the basic utilization formula defined in the etherStatsOctets attribute of RFC1757 as follows:


                                        Delta_Pkts * (9.6 + 6.4) + (Delta_Octets * 0.8)
Utilization = ----------------------------------------------------------------- * 100,000
                                                    Delta_sysUpTime * bandwidth

In the above 0x10d80, you will notice very large numbers for X_IN_UCAST_PKTS which indicates the device supports the 64 bit counter for ucast packets:

Initial X_IN_UCAST_PKTS: 395133432155898
Final X_IN_UCAST_PKTS: 395137727123232

However, the bandwidth parameters are too small to compute 64 bit counters:

PREVIOUS X_LOW_BANDWIDTH: 10000000
CURRENT X_LOW_BANDWIDTH: 10000000

PREVIOUS X_HIGH_BANDWIDTH: 10
CURRENT X_HIGH_BANDWIDTH: 10

(X_HIGH_BANDWIDTH is taken from the ifHighSpeed attribute in the ifMib which is defined as "An estimate of the interface's current bandwidth in units of 1,000,000 bits per second.)

Knowing the values Spectrum uses to compute load, load in and load out from the 0x10d80 and the formula Spectrum uses to compute load, load in and load out from the etherStatsOctets attribute of RFC1757, you can manually compute the values to verify the CA Spectrum results.

Solution:

The solution:

  1. If the device is modeled using SNMP V2 or V3, destroy the model and remodel using SNMP V1. This may prevent access to the 64 bit counter attributes so CA Spectrum will only use the 32 bit counters.
  2. Contact the vendor.