Cisco Voice Interfaces Test

Voice interfaces are the hardware and logical interfaces used to connect, process, and transport voice traffic between the router and external voice networks or endpoints. They allow the router to function as a voice gateway. Voice traffic is real-time, sensitive, and user-visible. Problems that might be tolerated for data can immediately break call quality or cause outages. The Cisco Voice Interfaces test monitors the interfaces in the target Cisco Router and reports the current state of each interface. In addition, this test reports the outages, signal stability, and call quality. This helps the administrators detect noise and distortion, faster troubleshooting, and reduced downtime earlier.

Target of the test : A Cisco Router

Agent deploying the test : An external agent

Outputs of the test : One set of results for each interface in the Cisco Router that is being monitored.

Configurable parameters for the test
Parameters Description

Test period

How often should the test be executed

Host

The IP address of the Cisco Router.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; the default is 161.

SNMPversion

By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.

SNMPCommunity

The SNMP community name that the test uses to communicate with the router. This parameter is specific to SNMP v1 and v2 only. Therefore, if the snmpversion chosen is v3, then this parameter will not appear.

Username

This parameter appears only when v3 is selected as the SNMPversion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 

Context

This parameter appears only when v3 is selected as the SNMPVERSION. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.

Authpass

Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3.

Confirm password

Confirm the Authpass by retyping it here.

Authtype

This parameter too appears only if v3 is selected as the SNMPversion. From the AuthType list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 - Message Digest Algorithm
  • SHA - Secure Hash Algorithm
  • SHA224 - Secure Hash Algorithm 224 bit
  • SHA256 - Secure Hash Algorithm 256 bit
  • SHA384 - Secure Hash Algorithm 384 bit
  • SHA512 - Secure Hash Algorithm 512 bit

Encryptflag

This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 

Encrypttype

If the EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES - Data Encryption Standard
  • 3DES - Triple Data Encryption Standard
  • AES - Advanced Encryption Standard
  • AES128 - Advanced Encryption Standard 128 bit
  • AES192 - Advanced Encryption Standard 192 bit
  • AES256 - Advanced Encryption Standard 256 bit

Encryptpassword

Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.

Timeout

Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

EngineID

This parameter appears only when v3 is selected as the SNMPVersion. Sometimes, the test may not report metrics when AES192 or AES256 is chosen as the Encryption type. To ensure that the test report metrics consistently, administrators need to set this flag to Yes. By default, this parameter is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Status

Indicates the current state of the router.

 

The values reported by this measure and its corresponding numeric equivalents are mentioned in the table below:

State Numeric Value
Down 0
Up 100
Admin turned off 200
Dormant 300
Not Present 400
Lower layer down 500

Note:

By default, this measure reports the above-mentioned states while indicating the current state of the router. However, the graph of this measure will be represented using the corresponding numeric equivalents of the states as mentioned in the table above.

Errored seconds

Indicates the number of errored seconds encountered by this interface during the last measurement period.

Number

An errored second is any one-second interval during which at least one transmission error is detected on the interface.

Very high value of this measure signifies a degraded line quality and leads directly to significant negative impacts on your voice services.

Severely errored seconds

Indicates the number of severely errored seconds encountered by this interface during the last measurement period.

Number

A severely errored second is any one-second interval in which the number of transmission errors exceeds a defined severe threshold, or the signal is badly impaired.

Line errored seconds

Indicates the number of line errored seconds encountered by this interface during the last measurement period.

Number

A line errored second is any one-second interval during which at least one line-level error is detected on the interface.

A very high value of this measure means the physical voice circuit is badly impaired and cannot reliably carry voice traffic.

Slip seconds

Indicates the number of controlled slip Seconds encountered by this interface during the last measurement period.

Number

A slip second is one second during which a clock slip occurs on a voice interface. A clock slip happens when the transmit clock and receive clock on a digital circuit are not synchronized.

A very high value of this measure denotes that clock slips are happening frequently which will directly impact voice quality and call stability.

Unavailable seconds

Indicates the number of unavailable seconds encountered by this interface during the last measurement period.

Number

An Unavailable Second is one second during which the interface is considered out of service because error conditions are too severe for normal operation.

This might be because of loss of signal, loss of frame, or excessive bit errors.

Severely errored frame seconds

Indicates the number of severely errored framing seconds encountered by this interface during the last measurement period.

Number

A Severely Errored Frame Second (SEFS) is one second during which framing errors are so frequent that the received frames cannot be reliably aligned or decoded.

A very high value of this measure might result in unstable signals and voice frames are discarded.

Bursty errored seconds

Indicates the number of Bursty Errored Seconds (BESs) encountered by this interface during the last measurement period.

Number

A Bursty Errored Second is one second in which errors occur in bursts, but not frequently enough to be classified as a Severely Errored Second (SES). During a bursty errored second, voice samples may be distorted, users may hear brief clicks, pops, or momentary distortion, signaling usually stays up but quality drops, or calls usually stay connected but sound poor.

Degraded minutes

Indicates the number of Degraded Minutes (DMs) encountered by this interface during the last measurement period.

Number

A Degraded Minute is any 60-second period during which the error rate on the circuit exceeds a defined threshold, but does not reach the severity of an outage. During degraded minutes, calls usually stay connected but call quality complaints increase.

Line code violations

Indicates the number of Line Coding Violations (LCVs) encountered by this interface during the last measurement period.

Number

A Line Code Violation happens when The receiver sees a pulse pattern that should not be possible if the line were healthy and correctly configured.

A very high value of this measure denotes that the signal on the wire is badly corrupted or encoded incorrectly.

Path code violations

Indicates the number of path coding violations encountered by this interface during the last measurement period.

Number

A path code violation occurs when the payload data fails an integrity check. Though the frame arrived, its contents are corrupted.