Virtual Server Test

Each real server group is mapped to a virtual server. The virtual server receives incoming client requests , uses a load-balancing algorithm to select an available real server in the group, and routes the requests to the selected real server.

Since application requests are front-ended by a virtual server, tracking the session load on a virtual server will reveal the load on the applications running on the real servers mapped to that virtual server. This also means that if the virtual server experiences a processing bottleneck, it is bound to impact load distribution and processing by the real servers, which will consequently affect user experience with the applications in the backend. To understand the load on your applications and to proactively detect any potential slowness that your applications may experience, it is good practice to continuously monitor each virtual server. This is exactly what the Virtual Server test does!

This test auto-discovers the virtual servers that are configured on the target load balancer and continuously monitors the current status of each virtual server and reveals how well each virtual server processes data. In addition, the test then reports how well the cache in each virtual server services requests. This way, you can figure out performance issues in the load-balancing virtual servers.

Target of the test : A JetNEXUS Load Balancer

Agent deploying the test : An external agent

Outputs of the test : One set of results for each Virtual server.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed


The IP address of the JetNEXUS load balancer that is being monitored.

SSH Port

Besides SNMP, this test also uses the Radware CLI to pull metrics on real servers. To run the CLI commands, the test first needs to establish an SSH connection with the Radware Alteon load balancer. To enable the test to establish this connection, specify the SSH Port here.

SSH Username, SSH Password, and Confirm Password

As stated earlier, this test also uses the Radware CLI to pull metrics on real servers. To use the CLI, the test first needs to connect to the Radware Alteon load balancer via SSH, and then run commands using CLI. For running the commands, this test requires the privileges of a valid SSH user with permission to run the CLI commands. Specify the user name and password of such a user against SSH UserName and SSH Password text boxes, and confirm the password by retyping it in the Confirm Password text box.


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


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.


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.


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. 


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.


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.


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


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. 


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


Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.


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.

Engine ID

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.

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


Indicates the current status of this virtual server.


The values that this measure can report and their corresponding numeric values are as follows:

Measure Value Numeric Value
Not connected 0
Offline 1
Standby 2
Online 3
Draining 4
Not monitored 5
Finding status 6
Not licensed 7
Unknown 8


By default, this measure reports one of the Measure Values listed in the table above to indicate the status of the real server. In the graph of the measure however, the real server status is indicated using the corresponding numeric equivalents only.

Use the detailed diagnosis of this measure to determine the IP address of the real server.

Data received

Indicates the rate at which data was received by this virtual server during the last measurement period.


Compare the values of these measures across the real servers to identify the server that is handling maximum traffic.

Data transmitted

Indicates the rate at which data was transmitted from this virtual server during the last measurement period.


Data cached

Indicates the rate at which the data was cached in this virtual server during the last measurement period.


Content Caching is a performance optimization feature that reduces server load and significantly increases the scalability of web-based applications, particularly those with peak, lumpy or unpredictable traffic profiles. For sites or applications with a large proportion of cacheable content, Caching can dramatically reduce the amount and size of requests to back-end servers.


Indicates the data compression percentage of this virtual server.



Total clients

Indicates the total number of clients established connection on this virtual server.



Hit count

Indicates the total number of requests received by this virtual server.



Cache hit count

Indicates the total number of requests serviced from the cache in this virtual server.



Cache hit

Indicates the percentage of requests serviced from the cache in this virtual server.


A high value is desired for this measure.