Network Test

This test monitors the network connectivity from an external location (e.g., the eG server) to a host system.

Target of the test : A host system

Agent deploying the test : An external agent

Outputs of the test : One set of outputs for every target host being monitored

Configurable parameters for this test
  1. Test period - How often should the test be executed
  2. Host - The host for which the test is to be configured.
  3. targets - In the TARGETS text box, specify a comma-separated list of name:IP address pairs. While the name is just a display name, the IP address refers to the IP to be monitored. This specification will ensure that the test pings multiple IP addresses. For example - mysql:192.168.0.102,egwebsite:209.15.165.127
  4. Packetsize - The size of packets used for the test (in bytes)
  5. Packetcount – The number of packets to be transmitted during the test
  6. Timeout - How long after transmission should a packet be deemed lost (in seconds)
  7. PacketInterval- Represents the interval (in milliseconds) between successive packet transmissions during the execution of the network test for a specific target.
  8. 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

Avg network delay

Indicates the average delay between transmission of packet to a target and receipt of the response to the packet at the source.

Secs

An increase in network latency could result from misconfiguration of the router(s) along the path, network congestion, retransmissions at the network, etc.

Min network delay

The minimum time between transmission of a packet and receipt of the response back.

Secs

A significant increase in the minimum round-trip time is often a sure sign of network congestion.

Packet loss

Indicates the percentage of packets lost during transmission from source to target and back.

Percent

Packet loss is often caused by network buffer overflows at a network router or by packet corruptions over the network. The detailed diagnosis for this measure provides a listing of routers that are on the path from the external agent to target server, and the delays on each hop. This information can be used to diagnose the hop(s) that could be causing excessive packet loss/delays.

Network availability

Indicates whether the network connection is available or not

Percent

A value of 100 indicates that the system is connected. The value 0 indicates that the system is not connected.

Typically, the value 100 corresponds to a Pkt_loss_pct of 0.

The detailed diagnosis capability of the Average delay measure, if enabled, lists the hop-by-hop connectivity and delay (see Figure 1). The information provided includes the HopCount, the IP of the Router, and the delay at the displayed hop (in milliseconds). In the event of a very high Average delay, a user can use this information to “zero-in” on the exact hop at which the delay has occurred, probe into the root-cause of the delay, and resolve the issue, so as to optimize network performance.

Figure 1 : Detailed diagnosis of the Average delay measure listing the hop-by-hop connectivity and delay

Note:

If the Network test is executed by a Linux agent, then this agent will not be able to collect the detailed measures (i.e., detailed diagnosis) for the Network test. To resolve this issue, do the following:

  1. Login to the eG manager and edit the eg_tests.ini file (in the /opt/egurkha/manager/config directory) on it.
  2. By default, the MaxHopsForNetworkTestDD parameter in the [agent_settings] section of the file is set to 3. Change this to 16 instead and save the file.