Ns TCP Test

This test monitors TCP connections and retransmissions handled by the NetScaler appliance.

Target of the test : A Citrix NetScaler Appliance

Agent deploying the test : An external agent

Outputs of the test : One set of results for every Citrix NetScaler being monitored

Configurable parameters for the test
  1. TEST PERIOD – How often should the test be executed
  2. Host – The host for which the test is to be configured
  3. Port – Refers to the port used by the Citrix NetScaler appliance. By default, this is NULL.
  4. snmpport - The port number through which the monitored component exposes its SNMP MIB.
  5. 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.
  6. SNMPCommunity – The SNMP community name that the test uses to communicate with the target device. This parameter is specific to SNMP v1 and v2 only. Therefore, if the snmpversion chosen is v3, then this parameter will not appear.
  7. 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. 
  8. authpass – Specify the password that corresponds to the above-mentioned username. This parameter once again appears only if the snmpversion selected is v3.
  9. confirm password – Confirm the authpass by retyping it here.
  10. 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
  1. encryptflag – This flag appears only when v3 is selected as the snmpversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the encryptflag is set to no by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the yes option. 
  2. 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
    • AES – Advanced Encryption Standard
  1. encryptpassword – Specify the encryption password here.
  2. confirm password – Confirm the encryption password by retyping it here.
  3. timeout – Specify the duration (in seconds) beyond which the SNMP query issues by this test should time out. The default period is 10 seconds.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Server connections

Indicates the number of server connections in the NetScaler device.

Number

 

Client connections

Indicates the number of client connections in the NetScaler device.

Number

 

Connections serving requests

Indicates the number of connections to the NetScaler device that are currently serving requests.

Number

This metric is a key indicator of the workload handled by the NetScaler device.

Server connections in established state

Indicates the number of server connections in NetScaler in established state.

Number

 

Client connections in established state

Indicates the number of client connections in NetScaler in established state.

Number

 

Spare connections

Indicates the number of spare connections ready to be used.

Number

 

Surge queue length

Indicates number of number of connections in surge queue.

Number

The NetScaler device can be used to limit the number of simultaneous requests that are passed on to a server. When a request is completed, additional requests are forwarded to the server. If a request arrives and the server is handling the maximum configured number of requests, the NetScaler device places the new request in a surge queue, where the request waits for its turn to be sent to the server for processing. The surge queue allows a server to run at peak capacity without the risk of having it spiral out of control because of a surge of incoming requests. The surge queue length indicates whether a server is able to keep up with its incoming workload or not. If the surge queue is consistently greater than 0, this indicates that the server is not able to keep up with the workload and additional server capacity is required. On the other hand, a periodic surge is not a cause for concern.

Server connections opened

Indicates the total number of opened server connections.

Number

 

Client connections opened

Indicates the total number of opened client connections.

Number

 

Data traffic received

Indicates the TCP traffic received during the last measurement period.

MB/Sec

 

Data transmit rate

Indicates the TCP traffic transmitted during the last measurement period.

MB/Sec

 

Connection establishment timeouts

Indicates the number of times connection establishment timed out during the last measurement period.

Number

 

Connection retries

Indicates the number of times TCP connection established was retried during the last measurement period.

Number

 

Client retransmissions

Indicates the number of retransmissions from clients during the last measurement period.

Number

Ideally, the number of retransmissions should be a small fraction (< 5%) of the total number of transmissions.

Server retransmissions

Indicates the number of retransmissions from servers during the last measurement period.

Number

Ideally, the number of retransmissions should be a small fraction (< 5%) of the total number of transmissions.

Retransmits sent

Indicates the number of retransmissions sent during the last measurement period.

Number

 

TCP retransmission failures

Indicates the number of retransmission failures during the last measurement period.

Number