Top-N Reports

Information About Top-N Reports

Top-N Reports Overview

Top-N reports allow you to collect and analyze data for each physical port on a switch. When Top-N reports start, they obtain statistics from the appropriate hardware counters and then go into sleep mode for a user-specified interval. When the interval ends, the reports obtain the current statistics from the same hardware counters, compare the current statistics from the earlier statistics, and store the difference. Top-N reports feature is supported only the Cisco Catalyst 9500 High Performance Series Switches. The statistics for each port are sorted by one of the statistic types that are listed below:

  • broadcast — Number of input/output broadcast packets

  • bytes — Number of input/output bytes

  • errors — Number of input errors

  • multicast — Number of input/output multicast packets

  • overflow — Number of buffer overflows

  • packets — Number of input/output packets

  • utilization — Utilization


Note
When calculating the port utilization, Top-N reports bundles the Tx and Rx lines into the same counter and also looks at the full-duplex bandwidth when calculating the percentage of utilization. For example, a Gigabit Ethernet port would be 2000-Mbps full duplex.

Top-N Reports Operation

When you enter the collect top command, processing begins and the system prompt reappears immediately. When processing completes, the reports are not displayed immediately on the screen; the reports are saved for later viewing. The Top-N reports notify you when the reports are complete by sending a syslog message to the screen.

How to use Top-N Reports

The following sections provide information on how to use Top-N Reports.

Enabling Top-N Reports

To enable Top-N reports creation, perform this task:

SUMMARY STEPS

  1. enable
  2. collect top [number_of_ports] counters interface {type | all | layer-2 | layer-3} [sort-by statistic_type] [interval seconds]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode. Enter your password if prompted.

Step 2

collect top [number_of_ports] counters interface {type | all | layer-2 | layer-3} [sort-by statistic_type] [interval seconds]

Example:

Device# collect top 4 counters interface all sort-by utilization interval 76

Enables Top-N reports creation.

  • type — type of interface — FastEthernet, GigabitEthernet, TenGigabitEthernet, FortyGigabitEthernet, TwentyFiveGigabitEthernet, HundredGigabitEthernet, Port-channel

When enabling Top-N reports creation, note the following information:

  • You can specify the number of busiest ports for which to create reports (the default is 20).

  • You can specify the statistic type by which ports are determined to be the busiest (the default is utilization). The supported values for statistic_type are broadcast , bytes , errors , multicast , overflow , packets , and utilization .

  • You can specify the interval over which statistics are collected (range: 0 through 999; the default is 30 seconds).

  • Except for a utilization report (configured with the sort-by utilization keywords), you can specify an interval of zero to create a report that displays the current counter values instead of a report that displays the difference between the start-of-interval counter values and the end-of-interval counter values.

Displaying Top-N Reports

To display Top-N reports, perform this task:

SUMMARY STEPS

  1. enable
  2. show top counters interface report [report_num]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode. Enter your password if prompted.

Step 2

show top counters interface report [report_num]

Example:

Device# show top counters interface report 1

Displays Top-N reports.

Note

 

To display information about all the reports, do not enter a report_num value.

Top-N reports statistics are not displayed in these situations:

  • f a port is not present during the first poll.

  • If a port is not present during the second poll.

  • If a port’s speed or duplex changes during the polling interval.

  • If a port’s type changes from Layer 2 to Layer 3 during the polling interval.

  • If a port’s type changes from Layer 3 to Layer 2 during the polling interval.

Clearing Top-N Reports

To clear Top-N reports, perform one of these tasks:

SUMMARY STEPS

  1. enable
  2. clear top counters interface report [report_num]

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode. Enter your password if prompted.

Step 2

clear top counters interface report [report_num]

Example:

Device# clear top counters interface report 4

Clears all the Top-N reports that have a status of done.

  • report_num — Specifies the report number that must be cleared regardless of the status

Examples : Top-N Reports

Enabling Top-N Reports

This example shows how to enable Top-N reports creation for an interval of 76 seconds for the four ports with the highest utilization:
Device# collect top 4 counters interface all sort-by utilization interval 76 
TopN collection started.

Displaying Top-N Reports

This example shows how to display information about all the Top-N reports:


Note

Reports for which statistics are still being obtained are shown with a status of pending.

 
# show top counters interface report

Id Start Time Int N Sort-By Status Owner
-- ---------------------------- --- --- --------- ------- ----------------------
1 08:18:25 UTC Tue Nov 23 2004 76 20 util done console
2 08:19:54 UTC Tue Nov 23 2004 76 20 util done console
3 08:21:34 UTC Tue Nov 23 2004 76 20 util done console
4 08:26:50 UTC Tue Nov 23 2004 90 20 util done console
This example shows how to display a specific Top-N report:
# show top counters interface report 1

Started By : console
Start Time : 08:18:25 UTC Tue Nov 23 2004
End Time : 08:19:42 UTC Tue Nov 23 2004
Port Type : All
Sort By : util
Interval : 76 seconds
Port Band Util Bytes Packets Broadcast Multicast In- Buf-
width (Tx + Rx) (Tx + Rx) (Tx + Rx) (Tx + Rx) err ovflw
------- ----- ---- ----------- ----------- ---------- ---------- ---- -----
 
Gi2/5 100 50 726047564 11344488 11344487 1 0 0
Gi2/48 100 35 508018905 7937789 0 43 0 0
Gi2/46 100 25 362860697 5669693 0 43 0 0
Gi2/47 100 22 323852889 4762539 4762495 43 0 0

Clearing Top-N Reports

This example shows how to remove all reports that have a status of done:
# clear top counters interface report

04:00:06: %TOPN_COUNTERS-5-DELETED: TopN report 1 deleted by the console
04:00:06: %TOPN_COUNTERS-5-DELETED: TopN report 2 deleted by the console
04:00:06: %TOPN_COUNTERS-5-DELETED: TopN report 3 deleted by the console
04:00:06: %TOPN_COUNTERS-5-DELETED: TopN report 4 deleted by the console
This example shows how to remove a report number 4:
# clear top counters interface report 4

04:52:12: %TOPN_COUNTERS-5-KILLED: TopN report 4 killed by the console