Configuring IP SLA - Percentile Support for Filtering Outliers
This module describes how to configure the percentile option for IP SLAs to examine a set of network measurements that are within a specified percentile of the return packets. This feature improves Cisco IP Service Level Agreements (SLAs) by providing the capability to measure round-trip times within a percentile, such as the 95th percentile of RTT, in order to examine a set of measurements that are 95% faster and 5% slower.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About IP SLA - Percentile Support for Filtering Outliers
Percentile Measurements
The IP SLA- Percentile Support for Filtering Outliers feature enables IP SLAs to calculate min/average/max values for all packets, excluding
those with the highest x% measured value. For example, if you have a ten-packet
probe with nine 1-ms RTT values
and one 50-ms RTT value, the percentile will exclude the
outlier (50-ms) and report a min/avg/max value of 1/1/1, not 1/5/50.
IP SLAs reactions are configured to trigger when a monitored value
exceeds or falls below a specified level. If IP SLAs measures
too high or too low for any configured reaction, IP SLAs can
generate a notification to a network management application or
trigger another IP SLA operation to gather more data.
The percentile
reactions work the same way except that the monitored value is
the percentile min/max/average.
A count is keep of all the packets that violate the threshold value and at the end of the operation, that value is subtracted from the total packets received, then divided by the total, and a success ratio is generated. This value is referenced by a new reaction type that generates a notification when a percentage ratio is not met. For information, see the ip sla reaction-configuration command in the IP SLAs Command Reference.
How to Configure IP SLA - Percentile Support for Filtering Outliers
Configuring the IP SLAs Responder on a Destination Device
 Note |
A responder should not configure a permanent port for a sender. If the responder configures a permanent port for a sender, even if the packets are successfully sent (no timeout or packet-loss issues), the jitter value is zero.
|
SUMMARY STEPS1.
enable
2.
configure
terminal
3.
Enter one of the following commands:
-
ip
sla
responder
-
ip
sla
responder
udp-echo
ipaddress
ip-address
port
portvrf
vrf
4.
end
DETAILED STEPS | Command or Action | Purpose |
---|
Step 1 |
enable
Example:
|
Enables privileged EXEC mode.
|
Step 2 |
configure
terminal
Example:
Device# configure terminal
|
Enters global configuration mode.
|
Step 3 | Enter one of the following commands:
-
ip
sla
responder
-
ip
sla
responder
udp-echo
ipaddress
ip-address
port
portvrf
vrf
Example:
Device(config)# ip sla responder
Device(config)# ip sla responder udp-echo ipaddress 192.0.2.132 port 5000 vrf vrf1
|
(Optional) Temporarily enables IP SLAs responder functionality on a Cisco device in response to control messages from the source.
(Optional; required only if protocol control is disabled on the source.) Enables IP SLAs responder functionality on the specified IP address, port and VRF.
|
Step 4 |
end
Example:
|
Exits global configuration mode and returns to privileged EXEC mode.
|
Configuring an IP SLAs Operation Using the Percentile Option
Before You Begin- The IP SLAs operation to be configured for percentile support must be configured on the source device. For configuration information, see the appropriate module in the IP SLAs Configuration Guide. The percentile option can be configured for the following IP SLAs operations:
Ethernet jitter—See the “Manually Configuring an IP SLAs Ethernet Ping or Jitter Operation on the Source Device” section of the “Configuring IP SLAs for Metro-Ethernet” module.
ICMP jitter—See the “Configuring Cisco IP SLAs ICMP Operations” module.
UDP jitter—See the “IP SLAs UDP Jitter Operations” module.
For a UDP jitter operation, an IP SLAs responder must be configured on the destination device. For configuration information, see the “Configuring an IP SLAs Responder on the Destination Device” section.
SUMMARY STEPS1.
enable
2.
configure terminal
3.
ip sla operation-number
4.
percentile {jitteravg | jitterds | jittersd | owds | owsd | rtt} percent
5.
end
DETAILED STEPS | Command or Action | Purpose |
---|
Step 1 |
enable
Example:
Device> enable
|
Enables privileged EXEC mode.
|
Step 2 | configure terminal
Example:
Device# configure terminal
|
Enters global configuration mode.
|
Step 3 | ip sla operation-number
Example:
Device(config)# ip sla 10
|
Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.
Note
| For the purpose of this configuration task, the operation to be configured for percentile support is a preconfigured ICMP jitter operation.
|
|
Step 4 | percentile {jitteravg | jitterds | jittersd | owds | owsd | rtt} percent
Example:
Device(config-ip-sla-jitter)# percentile jitteravg 95
|
Configures the percentile option for an IP SLAs operation.
|
Step 5 | end
Example:
Device(config-ip-sla-jitter)# end
|
Returns to privileged EXEC mode.
|
Scheduling IP SLAs
Operations
Before You Begin
- All IP Service Level
Agreements (SLAs) operations to be scheduled must be already configured.
- The frequency of all
operations scheduled in a multioperation group must be the same.
- The list of one or more
operation ID numbers to be added to a multioperation group must be limited to a
maximum of 125 characters in length, including commas (,).
SUMMARY STEPS1.
enable
2.
configure
terminal
3.
Enter one of
the following commands:
-
ip
sla
schedule
operation-number [life {forever |
seconds}]
[start-time
{[hh:mm:ss] [month
day |
day
month] |
pending |
now |
after
hh:mm:ss}] [ageout
seconds]
[recurring]
-
ip
sla
group
schedule
group-operation-number
operation-id-numbers
{schedule-period
schedule-period-range
|
schedule-together} [ageout
seconds]
frequency
group-operation-frequency [life {forever |
seconds}]
[start-time
{hh:mm [:ss] [month
day |
day
month] |
pending |
now |
after
hh:mm [:ss]}]
4.
end
5.
show
ip
sla
group
schedule
6.
show
ip
sla
configuration
DETAILED STEPS | Command or Action | Purpose |
---|
Step 1 |
enable
Example:
|
Enables
privileged EXEC mode.
|
Step 2 |
configure
terminal
Example:
Device# configure terminal
|
Enters global
configuration mode.
|
Step 3 | Enter one of
the following commands:
-
ip
sla
schedule
operation-number [life {forever |
seconds}]
[start-time
{[hh:mm:ss] [month
day |
day
month] |
pending |
now |
after
hh:mm:ss}] [ageout
seconds]
[recurring]
-
ip
sla
group
schedule
group-operation-number
operation-id-numbers
{schedule-period
schedule-period-range
|
schedule-together} [ageout
seconds]
frequency
group-operation-frequency [life {forever |
seconds}]
[start-time
{hh:mm [:ss] [month
day |
day
month] |
pending |
now |
after
hh:mm [:ss]}]
Example:
Device(config)# ip sla schedule 10 life forever start-time now
Device(config)# ip sla group schedule 10 schedule-period frequency
Device(config)# ip sla group schedule 1 3,4,6-9 life forever start-time now
Device(config)# ip sla schedule 1 3,4,6-9 schedule-period 50 frequency range 80-100
|
|
Step 4 |
end
Example:
|
Exits global
configuration mode and returns to privileged EXEC mode.
|
Step 5 |
show
ip
sla
group
schedule
Example:
Device# show ip sla group schedule
|
(Optional)
Displays IP SLAs group schedule details.
|
Step 6 |
show
ip
sla
configuration
Example:
Device# show ip sla configuration
|
(Optional)
Displays IP SLAs configuration details.
|
Troubleshooting Tips
If the IP Service Level Agreements (SLAs) operation is not running and not generating statistics, add the
verify-data command to the configuration (while configuring in IP SLA configuration mode) to enable data verification. When data verification is enabled, each operation response is checked for corruption. Use the
verify-data command with caution during normal operations because it generates unnecessary overhead.
Use the
debug
ip
sla
trace and
debug
ip
sla
error commands to help troubleshoot issues with an IP SLAs operation.
What to Do Next
To add proactive threshold conditions and reactive triggering for generating traps (or for starting another operation) to an IP Service Level Agreements (SLAs) operation, see the “Configuring Proactive Threshold Monitoring” section.
Verifying IP SLAs Operations
Perform this task to display and interpret the results of an IP SLAs operation. Check the output for fields that correspond to the criteria in your service level agreement to determine whether the service metrics are acceptable.
SUMMARY STEPS1.
enable
2.
show ip sla statistics
DETAILED STEPS
Step 1
|
enable
Enables privileged EXEC mode.
- Enter your password if prompted.
Example:
Device> enable
|
Step 2
|
show ip sla statistics
Displays and interprets the results of an IP SLAs operation.
Example:
Device> show ip sla statistics
|
Configuration Examples for IP SLA - Percentile Support for Filtering Outliers
Example: Configuring IP SLA - Percentile Support for Filtering Outliers
The following example shows how to configure an IP SLAs ICMP
jitter operation with the percentile option:
ip sla 1
icmp-jitter 192.168.0.129 interval 40 num-packets 100 source-ip 10.1.2.34
percentile jitteravg 95
!
ip sla reaction-configuration 1 react jitterAvgpct threshold-value 5 2 action-type trap threshold-type immediate
!
ip sla schedule 1 start-time now life forever
Additional References for IP SLA - Percentile Support for Filtering Outliers
Standards and RFCs
Standard/RFC |
Title |
CISCO-RTTMON-MIB
CISCO-RTTMON-ICMP-MIB
|
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
|
Technical Assistance
Description |
Link |
The Cisco Support website provides extensive online resources,
including documentation and tools for troubleshooting and
resolving technical issues with Cisco products and technologies.
To receive security and technical information about your
products, you can subscribe to various services, such as the
Product Alert Tool (accessed from Field Notices), the Cisco
Technical Services Newsletter, and Really Simple Syndication
(RSS) Feeds.
Access to most tools on the Cisco Support website requires a
Cisco.com user ID and password.
|
http://www.cisco.com/support
|
Feature Information for IP
SLA - Percentile Support for Filtering Outliers
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1 Feature Information for IP
SLA - Percentile Support for Filtering Outliers
Feature
Name
|
Releases
|
Feature
Information
|
IP SLA -
Percentile Support for Filtering Outliers
|
Cisco IOS 15.3(2)T
|
This
feature improves Cisco IP Service Level Agreements (SLAs) by providing the
capability to measure round-trip times within a percentile, such as the 95th percentile of RTT,
in order to examine a set of measurements that are 95% faster and 5% slower.
The
following commands were introduced or modified:
ip sla
reaction-configuration,
percentile,
show
ip sla statistics
|