Cisco Interfaces Test

This test monitors various statistics of interest for each interface of a Cisco router. It is intended to alert the operator whenever any abnormal activity is detected on any of the Cisco router's interfaces.

Target of the test : A Cisco device

Agent deploying the test : An external agent

Outputs of the test : One set of records for each interface of a router

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed

Host

The host for which the test is to be configured.

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 firewall. 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 the username 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.

Exclude

This text box takes a comma separated list of network interfaces that are to be excluded when performing the test. E.g., if this parameter has a value of "Null0", then the Null0 interface of the Cisco router will not be monitored by the eG agent.

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

Reliability value

Provides the level of reliability of the interface

Number

This is representative of how many errors are occurring on the interface. The best reliability value is 255.

 

Reliability percent

Indicates the reliability of an interface as a percentage

Percent

This is computed as (Reliability value)*100/255. A drop in the value of this measure indicates an error-prone interface.

Delay

The amount of delay of an interface

Secs

This value is measured and reported by the Cisco IOS. This is calculated by adding up the delay along the path to the next router. Any increase in this value is usually attributable to an increase in traffic over an interface.

Load factor

The degree of loading of an interface, reported as a percent.

Percent

A value of 100% indicates a saturated interface. Consider increasing the speed/capacity of the interface in this case.

Data received

The rate of data received by the router over an interface

MB/sec

This value is an indicator of the instantaneous traffic received
over an interface.

Data transmitted

The rate of data transmitted by the router over an interface

MB/sec

This value is an indicator of the instantaneous traffic transmitted over an interface.

In queue drops

Number of packets dropped during reception over the interface during the last measurement period.

Number

This value counts the number of packets that were not received (i.e., thrown away) because of lack of a system resource (e.g., a buffer). Packets can be dropped even if the number of packets queued on the input side is equal to the input queue limit. Ideally, there should be no queue drops. An increase in queue drops is an indicator that the router may not be able to service the traffic received by it.

Out queue drops

Number of packets dropped during transmission over the interface during the last measurement period

Number

This value counts the number of packets that were not transmitted (i.e., thrown away) because of various reasons. For example, packets can be dropped because the output queue occupancy has reached the pre-specified queue limit. Packet drops can also occur because of insufficient buffers - e.g., not having a hardware transmission buffer when a packet is fast-switched from one interface to another. Repeated queue drops can indicate congestion at the router.

Resets

Number of times an interface was reset in the last measurement period

Number

This value counts the number of times an interface internally reset. Repeated resets may be indicative of hardware problems in the router.

Restarts

Number of times an interface needed to be completely restarted in the last measurement period

Number

This value should be close to zero in most cases.

CRC errors

Number of input packets in the last measurement period that had cyclic redundancy checksum errors

Number

This value which is mainly relevant for serial lines is one of the factors that affects the reliability of the line.

Aborts

Number of packet receptions in the last measurement period that were aborted due to errors

Number

 

Collisions

Number of collisions that occurred over an interface during the last
measurement period

Number

This value which is mainly relevant for LAN interfaces is one of the factors affecting the reliability of the line.

Slow packets received

The rate at which packets routed with slow switching were received.

Packets/Sec

 

Slow packets transmitted

The rate at which packets routed with slow switching were transmitted.

Packets/Sec

 

Link protocol status

Indicates the current status of the link protocol.

 

The values that this measure can report and their corresponding numeric values have been outlined in the table below:

Measure Value Numeric Value

Up

1

Down

0

Note:

By default, this measure reports one of the Measure Values listed in the table above to indicate the status of the link protocol. The graph of this measure however, represents the same using the numeric equivalents only.