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Cisco IOS Software Releases 12.3 T

Service Assurance Agent (SAA) VoIP UDP Operation

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Service Assurance Agent (SAA)
VoIP UDP Operation

Contents

Prerequisites for SAA VoIP UDP Operations

Restrictions for SAA VoIP UDP Operations

Information About SAA VoIP UDP Operations

The Calculated Planning Impairment Factor (ICPIF)

Mean Opinion Scores (MOS)

Voice Performance Monitoring Using SAA

Codec Simulation Within SAA

The SAA ICPIF Value

The SAA MOS Value

How to Configure SAA VoIP UDP Operations

Configuration Example for SAA VoIP UDP Operations

SAA VoIP UDP Operation Configuration: Example

SAA VoIP UDP Operation Statistics Output: Example

Where to Go Next

Additional References

Related Documents

Related Standards

Related MIBs

Related RFCs

Technical Assistance

Command Reference

type jitter (codec)

show rtr collection-statistics

show rtr operational-state

Glossary


Service Assurance Agent (SAA)
VoIP UDP Operation

The Service Assurance Agent (SAA) Voice over IP (VoIP) User Datagram Protocol (UDP) Operation feature adds the capability to return approximate Mean Opinion Score (MOS) and Calculated Planning Impairment Factor (ICPIF) voice quality scores in the data collected by the SAA Jitter operation.

Release
Modification

12.3(4)T

This feature was introduced.


Feature History for SAA VoIP UDP Operation Feature

Finding Support Information for Platforms and Cisco IOS Software Images

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Contents

•Prerequisites for SAA VoIP UDP Operations

•Restrictions for SAA VoIP UDP Operations

•Information About SAA VoIP UDP Operations

•How to Configure SAA VoIP UDP Operations

•Configuration Example for SAA VoIP UDP Operations

•Where to Go Next

•Additional References

•Command Reference

•Glossary

Prerequisites for SAA VoIP UDP Operations

To use this feature, your networking devices on both ends of the connection must support SAA. SAA is an integrated feature of all Cisco IOS software-based platforms.

Restrictions for SAA VoIP UDP Operations

This feature uses UDP traffic to generate approximate Voice over IP scores. It does not provide support for the Real-Time Transport Protocol (RTP).

Note The term "Voice" in this document should be taken to mean any Internet telephony applications. For example, the term "Voice over IP" is commonly understood to include the transmission of multimedia (both voice and video) over IP networks.

ICPIF and MOS values provided by this feature are estimates only, and they are intended only for relative comparisons. The values may not match values determined using other methods.

Note Predictions of customer opinion (such as those listed for the E-Model transmission rating factor R and derived Mean Opinion Scores) determined by any method are intended only for transmission planning purposes and should not be interpreted as reflecting actual customer opinions.

This release supports only the following speech codecs (compression methods):

•G.711 A Law (g711alaw: 64 kbps PCM compression method)

•G.711 mu Law (g711ulaw: 64 kbps PCM compression method)

•G.729A (g729a: 8 kbps CS-ACELP compression method)

Information About SAA VoIP UDP Operations

To use the SAA VoIP UDP Operation feature, you should understand the following concepts:

•The Calculated Planning Impairment Factor (ICPIF)

•Mean Opinion Scores (MOS)

•Voice Performance Monitoring Using SAA

The Calculated Planning Impairment Factor (ICPIF)

The ICPIF originated in the 1996 version of ITU-T recommendation G.113, "Transmission impairments," as part of the formula Icpif = Itot - A. ICPIF is actually an initialism for "(Impairment) Calculated Planning Impairment Factor," but should be taken to simply mean the "calculated planning impairment factor." The ICPIF attempts to quantify, for comparison and planning purposes, the key impairments to voice quality that are encountered in the network.

The ICPIF is the sum of measured impairment factors (total impairments, or Itot) minus a user-defined access Advantage Factor (A) that is intended to represent the user's expectations, based on how the call was placed (for example, a mobile call versus a land-line call). In its expanded form, the full formula is expressed as:

Icpif = Io + Iq + Idte + Idd + Ie - A

where

•Io represents impairments caused by non-optimal loudness rating,

•Iq represents impairments caused by PCM quantizing distortion,

•Idte represents impairments caused by talker echo,

•Idd represents impairments caused by one way transmission times (one way delay),

•Ie represents impairments caused by equipment effects, such as the type of codec used for the call and packet loss, and

•A represents an access Advantage Factor (also called the user Expectation Factor) that compensates for the fact that users may accept some degradation in quality in return for ease of access.

ICPIF values are expressed in a typical range of 5 (very low impairment) to 55 (very high impairment). ICPIF values numerically less than 20 are generally considered "adequate." While intended to be an objective measure of voice quality, the ICPIF value is also used to predict the subjective effect of combinations of impairments. Table 1, taken from G.113 (02/96), shows how sample ICPIF values are expected to correspond to subjective quality judgement.

Table 1 Quality Levels as a Function of Total Impairment Factor ICPIF

Upper Limit for ICPIF
Speech Communication Quality

5

Very good

10

Good

20

Adequate

30

Limiting case

45

Exceptional limiting case

55

Customers likely to react strongly (complaints, change of network operator)


For further details on the ICPIF, see the 1996 version of the G.113 specification.

Note The latest version of the ITU-T G.113 Recommendation (2001), no longer includes the ICPIF model. Instead, it refers implementers to G.107: "The Impairment Factor method, used by the E-model of ITU-T G.107, is now recommended. The earlier method that used Quantization Distortion Units is no longer recommended."

The full E-Model (also called the ITU-T Transmission Rating Model), expressed as R = Ro - Is - Id - Ie + A, provides the potential for more accurate measurements of call quality by refining the definitions of impairment factors (see the 2003 version of the G.107 for details). Though the ICPIF shares terms for impairments with the E-Model, the two models should not be confused.

The SAA VoIP UDP Operation feature takes advantage of observed correspondences between the ICPIF, transmission rating factor R, and MOS values, but does not yet support the E-Model.

SAA uses a simplified ICPIF formula, defined in more detail later in this document.

Mean Opinion Scores (MOS)

The quality of transmitted speech is a subjective response of the listener. Each codec used for transmission of Voice over IP provides a certain level of quality. A common benchmark used to determine the quality of sound produced by specific codecs is MOS. With MOS, a wide range of listeners have judged the quality of voice samples sent using particular codecs, on a scale of 1 (poor quality) to 5 (excellent quality). The opinion scores are averaged to provide the mean for each sample. Table 2 shows MOS ratings and the corresponding description of quality for each value.

Table 2 MOS Ratings

Score
Quality
Description of Quality Impairment

5

Excellent

Imperceptible

4

Good

Just perceptible, but not annoying

3

Fair

Perceptible and slightly annoying

2

Poor

Annoying but not objectionable

1

Bad

Very annoying and objectionable


As the MOS ratings for codecs and other transmission impairments are known, an estimated MOS can be computed and displayed based on measured impairments. This estimated value is designated as MOS-CQE (Mean Opinion Score; Conversational Quality, Estimated) by the ITU in order to distinguish it from objective or subjective MOS values (see P.800.1 for details).

Voice Performance Monitoring Using SAA

One of the key metrics in measuring voice and video quality over an IP network is jitter. Jitter is the name used to indicate the variation in delay between arriving packets (inter-packet delay variance). Jitter affects voice quality by causing uneven gaps in the speech pattern of the person talking. Other key performance parameters for voice and video transmission over IP networks include latency (delay) and packet loss. SAA is an embedded active monitoring feature of Cisco IOS software that provides a means for simulating and measuring these parameters in order to ensure your network is meeting or exceeding service-level agreements with your users.

SAA provides a Jitter monitoring operation, which consists of UDP probe packets sent across the network from an origin device to a specific destination (called the operational target). This synthetic traffic1 is used to record the amount of jitter for the connection, as well as the round-trip time, per-direction packet loss, and one way delay time (one way latency). Data, in the form of collected statistics, can be displayed for multiple tests over a user-defined period of time, allowing you to see, for example, how the network performs at different times of the day, or over the course of a week. The Jitter probe has the advantage of utilizing the SAA (RTR) Responder to provide minimal latency at the receiving end.

The SAA VoIP UDP Operation feature adds the capability to return approximate MOS and ICPIF scores in the data collected by the SAA Jitter operation, in addition to the metrics already gathered by the Jitter operation. This SAA feature provides even more useful information in determining the performance of your VoIP network, thereby improving your ability to perform network assessment, troubleshooting, and health monitoring.

Codec Simulation Within SAA

The SAA Jitter operation computes statistics by sending n UDP packets, each of size s, sent t milliseconds apart, from a given source router to a given target router, at a given frequency f. The target router must be running the SAA Responder in order to process the probe operations.

To generate MOS and ICPIF scores, you specify the codec type used for the connection when configuring the Jitter operation. Based on the type of codec you configure for the operation, the number of packets (n), the size of each payload (s), the inter-packet time interval (t), and the operational frequency (f) will be auto-configured with default values. (See Table 3 for specifics.) However, you are given the option, if needed, to manually configure these parameters in the syntax of the type jitter command.

Table 3 shows the default parameters that are configured for the operation by codec.

Table 3 Default Jitter Operation Parameters by Codec

Codec
Default Request Size (Packet Payload) (s)
Default Interval Between Packets (t)
Default Number of Packets (n)
Frequency of Probe Operations (f)

G.711 mu-Law (g711ulaw)

160 + 12 RTP bytes

20 ms

1000

Once every 1 minute

G.711 A-Law (g711alaw)

160 + 12 RTP bytes

20 ms

1000

Once every 1 minute

G.729A (g729a)

20 + 12 RTP bytes

20 ms

1000

Once every 1 minute


For example, if you configure the Jitter operation to use the characteristics for the g711ulaw codec, by default a probe operation will be sent once a minute (f). Each probe operation would consist of 1000 packets (n), with each packet containing 180 bytes of synthetic data (s), sent 20 milliseconds apart (t).

The SAA ICPIF Value

ICPIF value computation with Cisco IOS software is based primarily on the two main factors that can impair voice quality: delayed packets and lost packets. Because packet delay and packet loss can be measured by SAA, the full ICPIF formula, Icpif = Io + Iq + Idte + Idd + Ie - A, is simplified by assuming the values of Io, Iq, and Idte are zero, resulting in the following formula:

Total Impairment Factor (Icpif) = Delay Impairment Factor (Idd) + Equipment Impairment Factor (Ie) - Expectation/Advantage Factor (A)

This means that the ICPIF value is computed by adding a Delay Impairment Factor, which is based on a measurement of delayed packets, and an Equipment Impairment Factor, which is based on a measurement of lost packets. From this sum of the total impairments measured in the network, an impairment variable (the Expectation Factor) is subtracted to yield the ICPIF.

This is the same formula used by Cisco Gateways to calculate the ICPIF for received VoIP data streams.

The Delay Impairment Factor

The Delay Impairment Factor (Idd) is a number based on the measured one way delay. In this context, one way delay is a combination of the One Way Transmission Delay, as measured by the SAA operation, combined with the static values (as defined in the ITU standards) for the Codec Delay, the Look Ahead Delay, and the Digital Signal Processing (DSP) Delay. Table 4 shows sample correspondences between the measured One Way Transmission Delay and Delay Impairment Factor values.

Table 4 Sample Correspondence of Measured Delay to ICPIF Delay Impairment

One Way Delay (in milliseconds)
Delay Impairment Factor

150 or less

0

200

3

250

10

300

15

350

20

400

25

500

30

600

35

800 or greater

40


As shown in Table 4, Delay Impairment calculations are determined linearly for One Way Delay measurements between 150 and 800 milliseconds.

The Equipment Impairment Factor

The Equipment Impairment Factor (Ie) is a number based on the amount of measured packet loss. The amount of measured packet loss, expressed as a percentage of total number of packets sent, corresponds an Equipment Impairment Factor that is defined by codec. Table 5 shows sample correspondences between the packet loss measured by SAA and Equipment Impairment Factor values.

Table 5 Sample Correspondence of Measured Packet Loss to ICPIF Equipment Impairment

Packet Loss
(as a percentage of total number of packets sent)
Equipment Impairment Value for PCM (G.711) Codecs
Equipment Impairment Value for the CS-ACELP (G.729A) Codec

0%

0

10

2%

12

20

4%

22

30

6%

28

38

8%

32

42


The Expectation Factor

The Expectation Factor, also called the Advantage Factor (A), is intended to represent the fact that users may accept some degradation in quality in return for ease of access. For example, a mobile phone user in a hard-to-reach location may have an expectation that the connection quality will not be as good as a traditional land-line connection. This variable is also called the Advantage Dactor (short for Access Advantage Factor) because it attempts to balance an increased access advantage against a decline in voice quality.

Table 6, adapted from ITU-T Rec. G.113, defines a set of provisional maximum values for A in terms of the service provided.

Table 6 Advantage Factor Recommended Maximum Values

Communication Service
Advantage / Expectation Factor:
Maximum value of A

Conventional wire-line (land-line)

0

Mobility (cellular connections) within a building

5

Mobility within a Geographical area or moving in a vehicle

10

Access to hard-to-reach location;
(for example, via multi-hop satellite connections)

20


These values are only suggestions. To be meaningful, the use of the factor A and its selected value in a specific application should be used consistently in any planning model you adopt. However, the values in Table 6 should be considered as the absolute upper limits for A.

The default Advantage Factor for SAA Jitter operations is always zero.

The SAA MOS Value

SAA uses an observed correspondence between ICPIF and MOS values to estimate an MOS value. Usage of the abbreviation MOS within the context of this feature should be taken to represent the MOS-CQE (Mean Opinion Score; Conversational Quality, Estimated).

The E model, as defined in G.107 (03/2003), predicts the subjective quality that is experienced by an average listener by combining the impairment caused by transmission parameters (such as loss and delay) into a single rating, the transmission rating factor R (the R Factor). This rating, expressed in a scale of 0 (worst) to 100 (best) can be used to predict subjective user reactions, such as the MOS. Specifically, the MOS can be obtained from the R Factor with a converting formula. Conversely, a modified inverted form can be used to calculate R Factors from MOS values.

There is also a relationship between the ICPIF value and the R Factor. SAA takes advantage of this correspondence by deriving the approximate MOS score from an estimated R Factor, which, in turn, is derived from the ICPIF score. Table 7 shows the resulting MOS values that will be generated for corresponding ICPIF values.

Table 7 Correspondence of ICPIF Values to MOS Values

ICPIF Range
MOS
Quality Category

0 - 3

5

Best

4 - 13

4

High

14 - 23

3

Medium

24 - 33

2

Low

34 - 43

1

Poor


SAA will always express the estimated MOS value as a whole number in the range of 1 to 5, with 5 being the best quality. A MOS value of 0 (zero) indicates that MOS data could not be generated for the operation.

How to Configure SAA VoIP UDP Operations

To return VoIP scores with SAA Jitter operation statistics, perform the following task.

SUMMARY STEPS

1. enable

2. configure terminal

3. rtr operation-number

4. type jitter

5. dest-ipaddr (optional)

6. dest-port (optional)

7. frequency (optional)

8. enhanced-history (optional)

9. owner (optional)

10. tag (optional)

11. vrf (optional)

12. hours-of-statistics kept (optional)

13. threshold (optional)

14. timeout (optional)

15. tos (optional)

16. verify-data (optional)

17. exit

18. rtr schedule

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

rtr operation-number

Example:

Router(config)# rtr 10

Specifies an identification number for the SAA operation to be configured, and enters SAA RTR configuration mode.

Step 4 

type jitter dest-ipaddr {hostname | ip-address} dest-port port-number codec codec-type [codec-numpackets number-of-packets] [codec-size number-of-bytes]
[codec-interval milliseconds] [advantage-factor value] [source-ipaddr {hostname | ip-address}] [source-port port-number] [control {enable | disable}]

Example:

Router(config-rtr)# type jitter dest-ipaddr 209.165.200.225 dest-port 16384 codec g711alaw advantage-factor 10

Configures the operation as a Jitter (codec) operation that will generate VoIP scores in addition to latency, jitter, and packet loss statistics.

•For the codec-type argument, use one of the following keywords:

–g711alaw—64 kbps PCM compression method

–g711ulaw—64 kbps PCM compression method

–g729a—8 kbps CS-ACELP compression method

•Specifying the codec-type will configure the appropriate default values for the codec-interval, codec-size, and codec-numpacket options. You should not specify values for the interval, size, and number of packet options unless you have a specific reason to override the defaults (for example, approximating a different codec).

•The value you specify for the advantage-factor will be subtracted from the measured impairment values. You can use this option to correct the ICPIF and MOS values for network conditions. The default advantage factor (expectation factor) is 0.

•When configuring a Jitter operation that uses a codec type, the dest-port should be an even numbered port in the range 16384 to 32766 or 49152 to 65534.

•Do not use the control keyword with this command. The control disable keyword combination will disable SAA RTR control packets and cause the operation to malfunction.The default is control enable.

•After entering this command, the command-line interface (CLI) enters SAA RTR Jitter configuration mode to allow you to specify optional characteristics for the operation.

Step 5 

dest-ipaddr ip-address

(Optional) Specifies the destination IP address for the operation.

•Use of this command will overwrite the IP address specified in the syntax of the type jitter command.

•This command allows you to change the target device for the operation without disabling and reenabling the operation type.

Step 6 

dest-port port-number

(Optional) The destination port number for the operation.

•Use of this command will overwrite the port number specified in the syntax of the type jitter command.

•This command allows you to change the target port for the operation without disabling and reenabling the operation type.

Step 7 

frequency seconds

Example:

Router(config-rtr-jitter)# frequency 45

(Optional) Configures how often a probe operation is performed (number of seconds between probes).

•When the operation is configured as type jitter (codec), by default the operation is configured to run once every 60 seconds.

Step 8 

enhanced-history interval seconds buckets number-of-buckets

Example: 
Router(config-rtr-jitter)# enhanced-history 
interval 900 buckets 100

(Optional) Enables enhanced history collection for the Jitter operation.

•To view collected enhanced history statistics, use the show rtr enhanced-history command.

•Enhanced-history statistics do not include voice scores.

Note Standard SAA history statistics are not available for Jitter operations.

Step 9 

owner owner-id

Example:

Router(config-rtr-jitter)# owner admin

(Optional) Allows you to specify a process owner for the operation, as a free text designation.

•This option may be helpful in identifying who originated an operation in an environment where many operations are being run.

Step 10 

tag text

Example:

Router(config-rtr-jitter)# tag TelnetPollServer1

(Optional) Allows you to specify a label to the operation, as a free text designation.

•This option may be helpful in grouping multiple operations from the same or different routers.

Step 11 

vrf vrf-name

Example:

Router(config-rtr-jitter)# vrf vpn-A

(Optional) Configures the Jitter operation to run over a specific VPN by binding the operation to a specific VRF table.

Step 12 

hours-of-statistics-kept hours

Example:

Router(config-rtr-jitter)# hours-of-statistics-kept 4


The number of hours for which statistics are kept.

•By default, the router will retain statistics for the last two hours the operation was running. If the operation runs more than the specified number of hours, the oldest data will be replaced by newer data.

•If the operation stops running, the data will be kept indefinitely, but for only the last x hours the operation was running. (For example, 2 hours worth of data will be kept in memory indefinitely.)

Step 13 

threshold milliseconds

Example:

Router(config-rtr-jitter)# threshold 2000


(Optional) Configures the rising threshold, in milliseconds, for timeout or connection-loss events.

•By default, if the response time is greater than 5000 milliseconds (5 seconds), this is considered to be a rising threshold crossing event. You can configure triggers for these events (such as SNMP traps) using the rtr reaction commands in global configuration mode.

Step 14 

timeout milliseconds

Example:

Router(config-rtr-jitter)# timeout 10000

(Optional) Configures the timeout value for a probe operation.

Step 15 

tos number

Example:

Router(config-rtr-jitter)# tos 160

(Optional) Sets the Type Of Service byte value (including IP Precedence data) for request packtes.

•For example, the Differentiated Services Code Point (DSCP) value 46 is ToS value 184.

Step 16 

verify-data

Example:

Router(config-rtr-jitter)# verify-data

(Optional) Configures SAA to check each probe response for data corruption.

Note Only use the verify-data command when you suspect corruption may be an issue. .

Step 17 

exit

Example:

Router(config-rtr-jitter)# exit

Router(config)#

Exits from SAA RTR Jitter configuration mode to global configuration mode.

Step 18 

rtr schedule operation-number [life {forever | seconds}] [start-time {pending | now | hh:mm day month}] [ageout seconds]

Example:

Router(config)# rtr schedule 10 life forever start-time now

Schedules the operation by specifying when the operation should start, and how long the operation should run.

•The life keyword is used to configure how long the operation actively collects information. The default life time of the operation is 3600 seconds (1 hour).

•The default state for this command is start-time pending. If the operation is in a pending state, you can define the conditions under which the operation makes the transition from pending to active with the rtr reaction-trigger global configuration command. When the operation is in an active state it immediately begins collecting information.

•After starting the operation, you can stop the operation and clear the operation from the configuration using the no rtr operation-number command in global configuration mode.

The following commands, available in SAA RTR Jitter configuration mode, are not valid for Jitter (codec) operations:

•buckets-of-history-kept

•filter-for-history

•lives-of-history-kept

•distributions-of-statistics-kept

•statistics-distribution-interval

•request-data-size

Note The show rtr configuration command will list the values for th e"Number of statistic distribution buckets kept" and "Statistic distribution interval (milliseconds)", but these values not not apply to Jitter (codec) operations.


You can check the statistics for the latest operation at any time using the show rtr operational-state command. To view collected statistics after letting the operation run for a desired amount of time, use the show rtr collection-statistics command.

Configuration Example for SAA VoIP UDP Operations

In the following example, a Jitter (codec) operation is configured, then output from the corresponding show commands is given. This example assumes that the SAA RTR Responder is enabled on the device at 209.165.200.225.

•SAA VoIP UDP Operation Configuration: Example

•SAA VoIP UDP Operation Statistics Output: Example

SAA VoIP UDP Operation Configuration: Example 

Router> enable 

Password: 

Router# configure terminal 

Enter configuration commands, one per line.  End with the end command.

Router(config)# rtr 10 

Router(config-rtr)# type jitter dest-ipaddr 209.165.200.225 dest-port 16384 codec g711alaw 
advantage-factor 2 

Router(config-rtr-jitter)# owner admin_bofh

Router(config-rtr-jitter)# exit 

Router(config)# rtr schedule 10 start-time now 

Router(config)# end 

Router#

Router# show running-config | begin rtr 10 


rtr 10

 type jitter dest-ipaddr 209.165.200.225 dest-port 16384 codec g711alaw advantage-factor 2

 owner admin_bofh

rtr schedule 10 start-time now

 .

 .

 .

Router# show rtr configuration 10 


Entry number: 10

Owner: admin_bofh

Tag: 

Type of operation to perform: jitter

Target address: 209.165.200.225

Source address: 0.0.0.0

Target port: 16384

Source port: 0

Operation timeout (milliseconds): 5000

Codec Type: g711alaw

Codec Number Of Packets: 1000

Codec Packet Size: 172

Codec Interval (milliseconds): 20

Advantage Factor: 2

Type Of Service parameters: 0x0

Verify data: No

Vrf Name: 

Control Packets: enabled

Operation frequency (seconds): 60

Next Scheduled Start Time: Start Time already passed

Life (seconds): 3600

Entry Ageout (seconds): never

Status of entry (SNMP RowStatus): Active

Connection loss reaction enabled: No

Timeout reaction enabled: No

Verify error enabled: No

Threshold reaction type: Never

Threshold (milliseconds): 5000

Threshold Falling (milliseconds): 3000

Threshold Count: 5

Threshold Count2: 5

Reaction Type: None

Number of statistic hours kept: 2

Number of statistic distribution buckets kept: 1

Statistic distribution interval (milliseconds): 20

Enhanced History:

When a codec type is configured for a Jitter operation, the standard Jitter "Request size (ARR data portion):", "Number of packets:" and "Interval (milliseconds):" parameters will not be displayed in the show rtr configuration command output. Instead, values for "Codec Packet Size:", "Codec Number of Packets", and "Codec Interval (milliseconds)" are displayed.

SAA VoIP UDP Operation Statistics Output: Example

Use the show rtr operational-state command and the show rtr collection-statistics command to show Voice scores (ICPIF and MOS values) for the Jitter (codec) operation. 

Router# show rtr operational-state 10 


Entry number: 10

Modification time: 12:57:45.690 UTC Sun Oct 26 2003

Number of operations attempted: 1

Number of operations skipped: 0

Current seconds left in Life: Forever

Operational state of entry: Active

Last time this entry was reset: Never

Connection loss occurred: FALSE

Timeout occurred: FALSE

Over thresholds occurred: FALSE

Latest RTT (milliseconds): 19

Latest operation start time: 12:57:45.723 Sun Oct 26 2003

Latest operation return code: OK

!

Voice Scores:

ICPIF:  20          MOS Score:  3

!

RTT Values:

NumOfRTT: 10     RTTAvg: 19      RTTMin: 19     RTTMax: 20

RTTSum:  191    RTTSum2: 3649

Packet Loss Values:

PacketLossSD: 0 PacketLossDS: 0

PacketOutOfSequence: 0  PacketMIA: 0    PacketLateArrival: 0

InternalError: 0        Busies: 0

Jitter Values:

NumOfJitterSamples: 9

MinOfPositivesSD: 0     MaxOfPositivesSD: 0

NumOfPositivesSD: 0     SumOfPositivesSD: 0     Sum2PositivesSD: 0

MinOfNegativesSD: 0     MaxOfNegativesSD: 0

NumOfNegativesSD: 0     SumOfNegativesSD: 0     Sum2NegativesSD: 0

MinOfPositivesDS: 1     MaxOfPositivesDS: 1

NumOfPositivesDS: 1     SumOfPositivesDS: 1     Sum2PositivesDS: 1

MinOfNegativesDS: 1     MaxOfNegativesDS: 1

NumOfNegativesDS: 1     SumOfNegativesDS: 1     Sum2NegativesDS: 1

Interarrival jitterout: 0       Interarrival jitterin: 0

One Way Values:

NumOfOW: 0

OWMinSD: 0      OWMaxSD: 0      OWSumSD: 0      OWSum2SD: 0

OWMinDS: 0      OWMaxDS: 0      OWSumDS: 0      OWSum2DS: 0


Router# show rtr collection-statistics 10 

Entry number: 10

Start Time Index: 12:57:45.931 UTC Sun Oct 26 2003

Number of successful operations: 60

Number of operations over threshold: 0

Number of failed operations due to a Disconnect: 0

Number of failed operations due to a Timeout: 0

Number of failed operations due to a Busy: 0

Number of failed operations due to a No Connection: 0

Number of failed operations due to an Internal Error: 0

Number of failed operations due to a Sequence Error: 0

Number of failed operations due to a Verify Error: 0

Voice Scores:

MinOfICPIF: 2   MaxOfICPIF: 20   MinOfMos: 3   MaxOfMos: 5

RTT Values:

NumOfRTT: 600   RTTAvg: 20      RTTMin: 19      RTTMax: 22

RTTSum: 12100   RTTSum2: 244292

Packet Loss Values:

PacketLossSD: 0 PacketLossDS: 0

PacketOutOfSequence: 0  PacketMIA: 0    PacketLateArrival: 0

InternalError: 0        Busies: 0


Jitter Values:

NumOfJitterSamples: 540

MinOfPositivesSD: 1     MaxOfPositivesSD: 1

NumOfPositivesSD: 26    SumOfPositivesSD: 26    Sum2PositivesSD: 26

MinOfNegativesSD: 1     MaxOfNegativesSD: 1

NumOfNegativesSD: 19    SumOfNegativesSD: 19    Sum2NegativesSD: 19

MinOfPositivesDS: 1     MaxOfPositivesDS: 1

NumOfPositivesDS: 43    SumOfPositivesDS: 43    Sum2PositivesDS: 43

MinOfNegativesDS: 1     MaxOfNegativesDS: 2

NumOfNegativesDS: 43    SumOfNegativesDS: 44    Sum2NegativesDS: 46

Interarrival jitterout: 0       Interarrival jitterin: 0

One Way Values:

NumOfOW: 0

OWMinSD: 0      OWMaxSD: 0      OWSumSD: 0      OWSum2SD: 0

OWMinDS: 0      OWMaxDS: 0      OWSumDS: 0      OWSum2DS: 0

Where to Go Next

For information on configuring additional characteristics of SAA operations, refer to the Cisco IOS Release 12.2 document, "Network Monitoring Using Cisco Service Assurance Agent." For additional command details, refer to the Cisco IOS Configuration Fundamentals and Network Management Command Reference for Release 12.3T.

Additional References

The following sections provide references related to the SAA VoIP UDP Operation feature.

Related Documents

Related Topic
Document Title

Voice over IP (VoIP) codecs

"Understanding Codecs: Complexity, Hardware Support, MOS, and Negotiation"

http://www.cisco.com/warp/public/788/voip/codec_complexity.html

Jitter in Packet Voice Networks

"Understanding Jitter in Packet Voice Networks (Cisco IOS Platforms)"

http://www.cisco.com/warp/public/788/voice-qos/jitter_packet_voice.html

Cisco Service Assurance Agent (SAA) configuration

"Network Monitoring Using Cisco Service Assurance Agent"

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/ffun_c/fcfprt3/fcf017.htm

PSTN Fallback for Voice Gateways

"SIP: Measurement-Based Call Admission Control for SIP"

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t15/ftcacsip.htm


Related Standards

Standard
Title

ITU-T Recommendation G.107 (2003)

The E-model, a computation model for use in transmission planning

ITU-T Recommendation G.113 (1996)

Transmission impairments

ITU-T Recommendation G.113 (2001)

Transmission impairments due to speech processing

ITU-T Recommendation G.711 (1998)

Pulse code modulation (PCM) of voice frequencies
(also known as the G.711 Voice Codec)

ITU-T Recommendation G.729 Annex A (1996)

Reduced complexity 8 kbit/s CS-ACELP speech codec
(also known as the G.729/A/B Speech Codec)

ITU-T Recommendation P.800.1 (2003)

Mean Opinion Score (MOS) terminology


Full support for these standards is not claimed.

ITU Telecommunication Standards ("ITU-T Recommendations In Force") can be obtained from http://www.itu.ch. Summary definitions are available from a variety of internet sources.

Related MIBs

MIB
MIB Link

CISCO-RTTMON-MIB
(The Cisco Service Assurance Agent MIB; also know as The Round Trip Time Monitor MIB)

REVISION: "200304150000Z"

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


Related RFCs

RFC1
Title

RFC 768

User Datagram Protocol

RFC 1889

RTP: A Transport Protocol for Real-Time Applications

1 Full support by this feature for listed RFCs is not claimed.


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml


Command Reference

This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3T command reference publications.

•type jitter (codec)

•show rtr collection-statistics

•show rtr operational-state

type jitter (codec)

To configure a Service Assurance Agent (SAA) Jitter operation that returns VoIP scores, use the type jitter (codec) command in SAA RTR configuration mode. To reset the operation type to null, use the no form of this command.

type jitter dest-ipaddr {hostname | ip-address} dest-port port-number codec codec-type [codec-numpackets number-of-packets] [codec-size number-of-bytes]
[codec-interval time-interval] [advantage-factor value]
[source-ipaddr {hostname | ip-address}] [source-port port-number] [control {enable | disable}]

no type jitter dest-ipaddr {hostname | ip-address} dest-port port-number codec codec-type

Syntax Description

dest-ipaddr {hostname | ip-address}

Destination for the operation, as an IP host name or IP address.

dest-port port-number

Specifies the destination port number. For Jitter (codec) operations, the port number should be an even number in the range of 16384 to 32766 or 49152 to 65534.

codec codec-type

Enables the generation of estimated Voice quality scores in the form of Calculated Planning Impairment Factor (ICPIF) and Mean Opinion Score (MOS) values. The codec type should match the encoding algorithm you are using for VoIP transmissions.

The following codec-type keywords are available:

•g711alaw—The G.711 A-Law codec (64 kbps transmission)

•g711ulaw—The G.711 muHmm-Law codec (64 kbps transmission)

•g729a—The G.729A codec (8 kbps transmission)

Configuring the codec type sets default values for the variables codec-numpackets, codec-size, and codec-interval in this command. See Table 8 for details.

codec-numpackets number-of-packets

(Optional) Specifies the number of packets to be transmitted per probe operation. The valid range is from 1 to 60000 packets. The default is 1000 packets.

codec-size number-of-bytes

(Optional) Specifies the number of bytes in each packet transmitted. (Also called the payload size or request size.) The valid range is from 16 to 1500 packets. The default varies by codec; see Table 8.

codec-interval milliseconds

Specifies the interval (delay) between packets that should be used for the operation, in milliseconds (ms). The valid range is from 1 to 60000 ms. By default, packets are sent 20 ms apart.

advantage-factor value

Specifies the expectation factor to be used for ICPIF calculations. This value is subtracted from the measured impairments to yield the final ICPIF value (and corresponding MOS value). See the "Usage Guidelines" section for recommended values. The valid range is from 0 to 20. The default is 0.

source-ipaddr {hostname | ip-address}

(Optional) Source IP address to be applied to operations, as a host name or IP address.

source-port port-number

(Optional) Source port that SAA probe packets should be sent from. All probe traffic for this Jitter operation will be sent from the specified port.

control {enable | disable}

(Optional) Enables or disables the sending of SAA control messages to the SAA RTR Responder.

By default, SAA control messages are sent to the target device to establish a connection with the SAA RTR Responder.

Note Control messages are enabled by default. Disabling the SAA control messages for Jitter operations is not recommended. If you disable SAA control messages, packet loss statistics and IP telephony scores will not be generated accurately.


Defaults

No SAA operation type is associated with the operation number being configured.

Command Modes

SAA RTR configuration (config-rtr)

Command History

Release
Modification

12.0(5)T

The type jitter command was introduced.

12.3(4)T

The type jitter (codec) command was introduced.


Usage Guidelines

The type jitter command is executed in SAA RTR configuration mode. You must configure the type of operation before you can configure any of the other characteristics of the operation.

Prior to sending operations to the target device, SAA sends control messages to the SAA RTR Responder to enable the destination port. You must enable the SAA RTR Responder on the target router (using the rtr responder command) for the Jitter operation to function correctly.

The type jitter (codec) command is a special implementation of the type jitter command. This command is documented separately from the standard type jitter command because when you specify the codec in the command syntax, the standard configuration options are replaced with codec-specific keywords and arguments.

The SAA Jitter operation computes statistics by sending n UDP packets, each of size s, sent t milliseconds apart, from a given source router to a given target router, at a given frequency f.

To generate MOS and ICPIF scores, you specify the codec type used for the connection when configuring the Jitter operation. Based on the type of codec you configure for the operation, the number of packets (n), the size of each payload (s), the inter-packet time interval (t), and the operational frequency (f) will be auto-configured with default values. (See Table 8 for specifics.) However, you are given the option, if needed, to manually configure these parameters in the syntax of the type jitter command.

Table 8 shows the default parameters that are configured for the operation by codec.

Table 8 Default Jitter Operation Parameters by Codec

Codec
Default Number of Packets (n); [codec-
numpackets]
Packet Payload (s)
[codec-size]1
Default Interval between Packets (t)
[codec-interval]
Frequency of Operations (f)

G.711 mu-Law (g711ulaw)

1000

160 bytes

20 milliseconds

Once every 60 seconds

G.711 A-Law (g711alaw)

1000

160 bytes

20 milliseconds

Once every 60 seconds

G.729A (g729a)

1000

20 bytes

20 milliseconds

Once every 60 seconds

1 The actual Request Size of each packet will contain an additional 12 bytes of RTP header data in order to simulate the RTP/UDP/IP/Layer2 protocol stack.


For example, if you configure the Jitter operation to use the characteristics for the g711ulaw codec, by default a probe operation will be sent once a minute (f). Each probe operation would consist of 1000 packets (n), with each packet containing 160 bytes (plus 12 header bytes) of synthetic data (s), sent 20 milliseconds apart (t).

Note that the operational frequency is configured with the frequency SAA RTR Jitter configuration mode command, and is not one of the syntax options of the type jitter command. In other words, use of the frequency command when configuring the Jitter (codec) operation is optional.

The advantage-factor value syntax allows you to specify an access Advantage Factor (also called the Expectation Factor). Table 9, adapted from ITU-T Rec. G.113, defines a set of provisional maximum values for Advantage Factors in terms of the service provided.

Table 9 Advantage Factor Recommended Maximum Values

Communication Service
Advantage / Expectation Factor:
Maximum value of A

Conventional wire-line (land-line)

0

Mobility (cellular connections) within a building

5

Mobility within a Geographical area or moving in a vehicle

10

Access to hard-to-reach location;
(for example, via multi-hop satellite connections)

20


These values are only suggestions. To be meaningful, the use of the factor A and its selected value in a specific application should be used consistently in any planning model you adopt. However, the values in Table 9 should be considered as the absolute upper limits for A. The default Advantage Factor for SAA Jitter operations is always zero.

Examples

In the following example, SAA operation 10 is created and configured as a Jitter (codec) operation using the destination IP address 209.165.200.225 and the destination port number 3000. The operation is configured to use the characteristics of the G.711 A-Law codec, which means the operation will consist of 1000 packets, each of 172 bytes (160 plus 12 header bytes), sent 20 milliseconds apart. The default value for the Advantage Factor is used, and by default the operation will run once a minute. 

Router(config)# rtr 10

Router(config-rtr)# type jitter dest-ipaddr 209.165.200.225 dest-port 3000 codec g711alaw

Router(config-rtr-jitter)# default frequency 

Router(config-rtr-jitter)# tag jitter-with-voice-scores 

Router(config-rtr-jitter)# exit 

Router(config)# end 

Router# show rtr configuration 10 


Entry number: 10

Owner: 

Tag: jitter-with-voice-scores

Type of operation to perform: jitter

Target address: 209.165.200.225

Source address: 0.0.0.0

Target port: 3000

Source port: 0

Operation timeout (milliseconds): 5000

Codec Type: g711alaw

Codec Number Of Packets: 1000

Codec Packet Size: 172

Codec Interval (milliseconds): 20

Advantage Factor: 0

 . 

 .

 .

Operation frequency (seconds): 60

 .

 .

 .

Related Commands

Command
Description

rtr

Specifies an SAA operation and enters SAA RTR configuration mode.

show rtr configuration

Displays the current configuration data specific to SAA operations.


show rtr collection-statistics

To display statistical errors for all Service Assurance Agent (SAA) operations or a specified operation, use the show rtr collection-statistics command in EXEC mode.

show rtr collection-statistics [operation-number] [tabular | full]

Syntax Description

operation-number

(Optional) Number of the SAA operation to display.


Defaults

Shows statistics for the past two hours.

Command Modes

EXEC

Command History

Release
Modification

11.2

This command was introduced.

12.0(5)T

The output for this command was expanded to show information for Jitter operations.

12.1

The tabular and full keywords were removed.

12.1(1)T

The output for this command was expanded to show information for the FTP operation type and for One Way Delay Jitter operations.

12.2(8)T, 12.2(8)S

Output for "NumOfJitterSamples" was added (CSCdv30022).

12.2(11)T

The SAA Engine II was implemented. The maximum number of operations was increased from 500 to 2000.

12.3(4)T

Output (MOS and ICPIF scores) for the Jitter (codec) operation type was added.


Usage Guidelines

Use the show rtr collection-statistics command to display information such as the number of failed operations and the failure reason. You can also use the show rtr distribution-statistics and show rtr totals-statistics commands to display additional statistical information.

This command shows information collected over the past two hours, unless you specify a different amount of time using the hours-of-statistics-kept command.

For One Way Delay Jitter operations, the clocks on each device must be synchronized using NTP (or GPS systems). If the clocks are not synchronized, one way measurements are discarded. (If the sum of the source to destination (SD) and the destination to source (DS) values is not within 10 percent of the round trip time, the one way measurement values are assumed to be faulty, and are discarded.)

Examples

The following is sample output from the show rtr collection-statistics command, where operation 10 is a Jitter (codec) operation: 

Router# show rtr collection-statistics


Entry Number: 10


Start Time Index: 12:57:45.931 UTC Wed Mar 12 2003

Number of successful operations: 60

Number of operations over threshold: 0

Number of failed operations due to a Disconnect: 0

Number of failed operations due to a Timeout: 0

Number of failed operations due to a Busy: 0

Number of failed operations due to a No Connection: 0

Number of failed operations due to an Internal Error: 0

Number of failed operations due to a Sequence Error: 0

Number of failed operations due to a Verify Error: 0

Voice Scores:

 MinOfICPIF: 2   MaxOfICPIF:  20   MinOfMos: 3   MaxOfMos: 5

RTT Values:

 NumOfRTT: 600  RTTSum: 3789  RTTSum2: 138665

 Packet Loss Values:

 PacketLossSD: 0  PacketLossDS: 0

 PacketOutOfSequence: 0  PacketMIA: 0  PacketLateArrival: 0

 InternalError: 0  Busies: 0

Jitter Values:

 NumOfJitterSamples: 540

 MinOfPositivesSD: 1   MaxOfPositivesSD: 2

 NumOfPositivesSD: 26  SumOfPositivesSD: 31   Sum2PositivesSD: 41

 MinOfNegativesSD: 1   MaxOfNegativesSD: 4

 NumOfNegativesSD: 56  SumOfNegativesSD: 73   Sum2NegativesSD: 133

 MinOfPositivesDS: 1   MaxOfPositivesDS: 338

 NumOfPositivesDS: 58  SumOfPositivesDS: 409  Sum2PositivesDS: 114347

 MinOfNegativesDS: 1   MaxOfNegativesDS: 338

 NumOfNegativesDS: 48  SumOfNegativesDS: 396  Sum2NegativesDS: 114332

 Interarrival jitterout: 0       Interarrival jitterin: 0

One Way Values:

 NumOfOW: 440

 OWMinSD: 2  OWMaxSD: 6    OWSumSD: 1273  OWSum2SD: 4021

 OWMinDS: 2  OWMaxDS: 341  OWSumDS: 1643  OWSum2DS: 120295

The values shown indicate the aggregated values for the current hour. RTT stands for Round-Trip-Time. SD stands for Source-to-Destination. DS stands for Destination-to-Source. OW stands for One Way. Table 10 describes the significant fields shown in this output.

Table 10 show rtr collection-statistics Field Descriptions 

Field
Description

Voice Scores:

Indicates that Voice over IP statistics appear on the following lines. Voice score data is computed when the operation type is configured as type jitter (codec).

 ICPIF

The Calculated Planning Impairment Factor (ICPIF) value for the operation. The ICPIF value is computed by SAA using the formula Icpif = Io + Iq + Idte + Idd + Ie - A, where

•the values for Io, Iq, and Idte are set to zero,

•the value Idd is computed based on the measured one way delay,

•the value Ie is computed based on the measured packet loss,

•and the value of A is specified by the user.

ICPIF values are expressed in a typical range of 5 (very low impairment) to 55 (very high impairment). ICPIF values numerically less than 20 are generally considered "adequate."

Note This value is intended only for relative comparisons, and may not match ICPIF values generated using alternate methods.

  MinOfICPIF:

The lowest (minimum) ICPIF value computed for the collected statistics.

  MaxOfICPIF:

The highest (maximum) ICPIF value computed for the collected statistics.

 Mos

The estimated Mean Opinion Score (Conversational Quality, Estimated) for the latest iteration of the operation. The MOS-CQE is computed by SAA as a function of the ICPIF.

MOS values are expressed as a whole number from 1 to 5, with 5 being the highest level of quality, and 1 being the lowest level of quality. A MOS value of 0 (zero) indicates that MOS data could not be generated for the operation.

  MinOfMos:

The lowest (minimum) MOS value computed for the collected statistics.

  MaxOfMos:

The highest (maximum) ICPIF value computed for the collected statistics.

RTT Values:

Indicates that Round-Trip-Time statistics appear on the following lines.

 NumOfRTT

The number of successful round trips.

 RTTSum

The sum of all successful round trip values (in milliseconds).

 RTTSum2

The sum of squares of those round trip values (in milliseconds).

 PacketLossSD

The number of packets lost from source to destination.

 PacketLossDS

The number of packets lost from destination to source.

 PacketOutOfSequence

The number of packets returned out of order.

 PacketMIA

The number of packets lost where the direction (SD/DS) cannot be determined.

 PacketLateArrival

The number of packets that arrived after the timeout.

 InternalError

The number of times an operation could not be started due to other internal failures.

 Busies

The number of times this operation could not be started because the previously scheduled run was not finished.

Jitter Values:

Indicates that Jitter statistics appear on the following lines.

Jitter is inter-packet delay variance.

 NumOfJitterSamples:

The number of jitter samples collected. This is the number of samples that are used to calculate the following jitter statitstics.

 MinOfPositivesSD
 MaxOfPositivesSD

The minimum and maximum positive jitter values from source to destination, in milliseconds.

 NumOfPositivesSD

The number of jitter values from source to destination that are positive (i.e., network latency increases for two consecutive test packets).

 SumOfPositivesSD

The sum of those positive values (in milliseconds).

 Sum2PositivesSD

The sum of squares of those positive values.

 MinOfNegativesSD
 MaxOfNegativesSD

The minimum and maximum negative jitter values from source to destination. The absolute value is given.

 NumOfNegativesSD

The number of jitter values from source to destination that are negative (i.e., network latency decreases for two consecutive test packets).

 SumOfNegativesSD

The sum of those values.

 Sum2NegativesSD

The sum of the squares of those values.

 Interarrival jitterout:

The source to destination(SD) jitter value calculation, as defined in RFC 1889.

 Interarrival jitterin:

The destination to souce (DS) jitter value calculation, as defined in RFC 1889.

One Way Values

Indicates that one way measurement statistics appear on the following lines.

One Way (OW) Values are the amount of time it took the packet to travel from the source router to the target router (SD) or from the target router to the source router (DS).

 NumOfOW

Number of successful one way time measurements.

 OWMinSD

Minimum time from the source to the destination.

 OWMaxSD

Maximum time from the source to the destination.

 OWSumSD

Sum of the OWMinSD and OWMaxSD values.

 OWSum2SD

Sum of the squares of the OWMinSD and OWMaxSD values.


The DS values show the same information as above for Destination-to-Source Jitter values.

Related Commands

Command
Description

show ntp status

Displays the status of the Network Time Protocol configuration on your system.

show rtr configuration

Displays configuration values including all defaults for all SA Agent operations or the specified operation.

show rtr distributions-statistics

Displays statistic distribution information (captured response times) for all SAA operations or the specified operation.

show rtr totals-statistics

Displays the total statistical values (accumulation of error counts and completions) for all SAA operations or the specified operation.


show rtr operational-state

To display the operational state of all Service Assurance Agent (SAA) operations or a specified operation, use the show rtr operational-state command in EXEC mode.

show rtr operational-state [operation-number]

Syntax Description

operation-number

(Optional) Number of the SAA operation to display.


Defaults

Displays output for all running SAA operations.

Command Modes

EXEC

Command History

Release
Modification

11.2

This command was introduced.

12.0(5)T

Output for the Jitter operation type was added.

12.1

The tabular and full keywords were removed.

12.2(8)T, 12.2(8)S

Output for "NumOfJitterSamples" was added (CSCdv30022).

12.3(4)T

Output (MOS and ICPIF scores) for the Jitter (codec) operation type was added.


Usage Guidelines

Use the show rtr operational-state command to determine whether a connection loss, timeout, and over threshold occurred; how much life the operation has left; whether the operation is active; and the completion time. It also displays the results of the latest operation attempt.

Examples

The following example shows sample output from the show rtr operational-state command when the specified operation is a Jitter (codec) operation: 

Router# show rtr operational-state

        Current Operational State

Entry number: 10

Modification time: 12:57:45.690 UTC Sun Oct 26 2003

Number of operations attempted: 3

Number of operations skipped: 0

Current seconds left in Life: 3570

Operational state of entry: Active

Last time this entry was reset: Never

Connection loss occurred: FALSE

Timeout occurred: FALSE

Over thresholds occurred: FALSE

Latest RTT (milliseconds): 19

Latest operation start time: 12:57:45.723 Sun Oct 26 2003

Latest operation return code: OK

Voice Scores:

 ICPIF:  20          MOS Score:  3

RTT Values:

 NumOfRTT: 10     RTTAvg: 19      RTTMin: 19     RTTMax: 20

 RTTSum:  191    RTTSum2: 3649

Packet Loss Values:

 PacketLossSD: 0 PacketLossDS: 0

 PacketOutOfSequence: 0  PacketMIA: 0    PacketLateArrival: 0

 InternalError: 0        Busies: 0

Jitter Values:

 NumOfJitterSamples: 9

 MinOfPositivesSD: 0     MaxOfPositivesSD: 0

 NumOfPositivesSD: 0     SumOfPositivesSD: 0     Sum2PositivesSD: 0

 MinOfNegativesSD: 0     MaxOfNegativesSD: 0

 NumOfNegativesSD: 0     SumOfNegativesSD: 0     Sum2NegativesSD: 0

 MinOfPositivesDS: 1     MaxOfPositivesDS: 1

 NumOfPositivesDS: 1     SumOfPositivesDS: 1     Sum2PositivesDS: 1

 MinOfNegativesDS: 1     MaxOfNegativesDS: 1

 NumOfNegativesDS: 1     SumOfNegativesDS: 1     Sum2NegativesDS: 1

 Interarrival jitterout: 0       Interarrival jitterin: 0

One Way Values:

 NumOfOW: 0

 OWMinSD: 0      OWMaxSD: 0      OWSumSD: 0      OWSum2SD: 0

 OWMinDS: 0      OWMaxDS: 0      OWSumDS: 0      OWSum2DS: 0

The values shown indicate the values for the last SAA operation. RTT stands for Round-Trip-Time. SD stands for Source-to-Destination. DS stands for Destination-to-Source. OW stands for One Way. The * symbol in front of the time stamps indicates the time is synchronized using NTP or SNTP. Table 11 describes the significant fields shown in this output.

Table 11 show rtr operational-state Field Descriptions 

Field
Description

Voice Scores:

Indicates that Voice over IP statistics appear on the following lines. Voice score data is computed when the operation type is configured as type jitter (codec).

 ICPIF:

The Calculated Planning Impairment Factor (ICPIF) value for the latest iteration of the operation. The ICPIF value is computed by SAA using the formula Icpif = Io + Iq + Idte + Idd + Ie - A, where

•the values for Io, Iq, and Idte are set to zero,

•the value Idd is computed based on the measured one way delay,

•the value Ie is computed based on the measured packet loss,

•and the value of A is specified by the user.

ICPIF values are expressed in a typical range of 5 (very low impairment) to 55 (very high impairment). ICPIF values numerically less than 20 are generally considered "adequate."

Note This value is intended only for relative comparisons, and may not match ICPIF values generated using alternate methods.

 MOS:

The estimated Mean Opinion Score (Conversational Quality, Estimated) for the latest iteration of the operation. The MOS-CQE is computed by SAA as a function of the ICPIF.

MOS values are expressed as a whole number from 1 to 5, with 5 being the highest level of quality, and 1 being the lowest level of quality. A MOS value of 0 (zero) indicates that MOS data could not be generated for the operation.

RTT Values:

Indicates that Round-Trip-Time statistics appear on the following lines.

 NumOfRTT

The number of successful round trips.

 RTTSum

The sum of those round trip values (in milliseconds).

 RTTSum2

The sum of squares of those round trip values (in milliseconds).

Packet Loss Values:

Indicates that Packet Loss statistics appear on the following lines.

 PacketLossSD

The number of packets lost from source to destination.

 PacketLossDS

The number of packets lost from destination to source.

 PacketOutOfSequence

The number of packets returned out of order.

 PacketMIA

The number of packets lost where the direction (SD or DS) cannot be determined (MIA: "missing in action").

 PacketLateArrival

The number of packets that arrived after the timeout.

 InternalError

The number of times an operation could not be started due to other internal failures.

 Busies

The number of times this operation could not be started because the previously scheduled run was not finished.

Jitter Values:

Indicates that jitter operation statistics appear on the following lines.

Jitter is inter-packet delay variance.

 NumOfJitterSamples:

The number of jitter samples collected. This is the number of samples that are used to calculate the following jitter statitstics.

 MinOfPositivesSD
 MaxOfPositivesSD

The minimum and maximum positive jitter values from source to destination, in milliseconds.

 NumOfPositivesSD

The number of jitter values from source to destination that are positive (i.e., network latency increases for two consecutive test packets).

 SumOfPositivesSD

The sum of those positive values (in milliseconds).

 Sum2PositivesSD

The sum of squares of those positive values.

 MinOfNegativesSD
 MaxOfNegativesSD

The minimum and maximum negative jitter values from source to destination. The absolute value is given.

 NumOfNegativesSD

The number of jitter values from source to destination that are negative (i.e., network latency decreases for two consecutive test packets).

 SumOfNegativesSD

The sum of those values.

 Sum2NegativesSD

The sum of the squares of those values.

 Interarrival jitterout:

The source to destination(SD) jitter value calculation, as defined in RFC 1889.

 Interarrival jitterin:

The destination to souce (DS) jitter value calculation, as defined in RFC 1889.

One Way Values

Indicates that One Way measurement statistics appear on the following lines.

One Way (OW) Values are the amount of time it took the packet to travel from the source router to the target router (SD) or from the target router to the source router (DS).

 NumOfOW

Number of successful one way time measurements.

 OWMinSD

Minimum time from the source to the destination.

 OWMaxSD

Maximum time from the source to the destination.

 OWSumSD

Sum of the OWMinSD and OWMaxSD values.

 OWSum2SD

Sum of the squares of the OWMinSD and OWMaxSD values.


 

The DS values show the same information as above for Destination-to-Source Jitter values.

Related Commands

Command
Description

show rtr configuration

Displays configuration values including all defaults for all SAA operations or a specified operation.


Glossary

codec—In the context of IP Telephony, a codec is a compression and decompression algorithm used to transfer voice and video data more efficiently. Voice codec types are typically referred to using the ITU recommendation number that defines the algorithm (for example, "G.711" instead of "PCM").

CS-ACELP—The codec type defined in the reference documents G.729 and G.729A, Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP).

ITU—The International Telecommunication Union. The ITU is an international organization within the United Nations System where governments and the private sector coordinate global telecom networks and services. The ITU Telecommunication Standardization Sector (ITU-T), responsible for defining standards (Recommendations) covering all fields of telecommunications, is one of the three operational sectors of the ITU. The ITU web site is at http://www.itu.int.

ITU-T—ITU Telecommunication Standardization Sector. The ITU-T is one of the three operational sectors of the ITU, and is responsible for defining standards (called ITU-T Recommendations) covering all fields of telecommunications.

MOS-CQE (Mean Opinion Score; Conversational Quality, Estimated)—The score calculated by a network planning model which aims at predicting the quality in a conversational application situation. Estimates of conversational quality carried out according to ITU-T Rec. G.107, when transformed to a mean opinion score (MOS), give results in terms of MOS-CQE.2

PCM—The codec type defined in the reference document G.711, Pulse code modulation (PCM) of voice frequencies.

Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.

Copyright © 2003 Cisco Systems, Inc. All rights reserved.

1 The term "synthetic traffic" indicates that the network traffic is simulated; that is, the traffic is generated by SAA.
2 Definition from ITU-T Recommendation P.800.1. Used in accordance with the ITU Copyright and Disclaimer Notice.