Top Sources Test

While the Net flows test points you to the specific network flows that are trafficking large volumes of data over the network, the Top Sources test reveals those hosts whose interactions with other hosts in the environment are resulting in the generation of such data. In the event of a network slowdown, you can use this test to accurately identify hosts whose current network activities are 'suspect' - i.e., you can isolate those hosts that may be engaged in bandwidth-intensive transactions with other hosts, and could hence be contributing to the slowdown.

Target of the test : A Cisco device

Agent deploying the test : An external agent

Outputs of the test : One set of results for every source host.

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.

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.

Report Host Names

This test captures statistics on traffic that originates from source hosts, where each host is by default represented by its IP address in the eG monitoring console. Accordingly, this flag is set to No by default. You can set this flag to Yes so that the names of the individual hosts are displayed in the eG monitoring console instead of their IP addresses.

Minimum Flow Percent

By default, the value 3 is displayed here. This indicates that, by default, the test will consider only those sources that are using 3% or more of current traffic. You can increase or decrease this value based on your monitoring needs. If you set this value to 0, then all net flows will be monitored. 

Report No Of Flows Limit

By default, this parameter is set to all indicating that this test will monitor all sources by default. If you want the test to report, say only the top 5 sources in terms of the amount of traffic they generate in their net flows, then set this value to 5.

Ignore Local Traffic

By default, this flag is set to Yes, indicating that the test will ignore the sources of all the intranet traffic on the router. If you want the test to report metrics pertaining to the sources of local traffic as well, set this flag to No.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency. 

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Data from this source

Indicates the amount of data transmitted by this source over the network.

KB

Compare the value of this measure across sources to identify which source host is contributing to the high level of network traffic.

Use the detailed diagnosis of this measure to determine the top net flows (in terms of the volume of data transacted) that originated from this source, and the amount of data transacted in bytes and packets in every flow.

This source as fraction of top network flows

Indicates the percentage of top network flows in which this host is the source.

Percent

Compare the value of this measure across sources to know which source is part of many top net flows. A high value is indicative of a 'suspect' source.

Packets from this source

Indicates the number of data packets transmitted by this source over the network. 

Pkts

Compare the value of this measure across sources to identify which source host is contributing to the high level of network traffic.

 

Use the detailed diagnosis of the Data from this source measure to determine the top net flows (in terms of the volume of data transacted) that originated from a particular source, and the amount of data transacted in bytes and packets in every flow. With the help of this detailed diagnosis, you can quickly compare the top net flows, know which net flow generated the maximum traffic, and figure out which destination that traffic was leading to. Once the problem destination is isolated, you can then investigate why traffic to that destination was high - is it because of the type of application executing on that destination? (eg., an online game or a movie that would typically consume a lot of bandwidth), or is it because of a poor network line connecting the source and the destination?

Figure 1 : The detailed diagnosis of the Data from this source measure