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
|
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:
- Login to the eG manager and edit the eg_tests.ini file (in the /opt/egurkha/manager/config directory) on it.
- 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.