Ping

Description

Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to a destination computer. The hosts can reside inside or outside your network.

By using Ping you can find out if any of the IP hosts have a problem, and correlating Ping responses from different hosts helps you pin down where problems occur.

When you start Ping testing, the Netrounds Test Agents will continuously send ICMP Ping messages towards the hosts you have specified and collect statistics on response times and packet loss.

Read more about Ping here.

In the advanced options you can enable path tracing. The Test Agents will then first determine the path to the destination host. This is done by using traceroute to send UDP packets to the destination with increasing TTL (Time-To-Live) values. Once all the nodes in the path are known, the Test Agents will use Ping to monitor the round-trip time towards each node.

Besides ICMP-based Ping, UDP Echo is also supported. This is a UDP-based echo service, where a server listens for UDP echo requests on a UDP port. When such a frame is received, its data is sent back in an answering frame ("echo respond"). The metrics are the same as those retrievable with ICMP Ping. The UDP Echo protocol is defined in IETF RFC 862.

Setting up a test or monitoring

To run Netrounds Ping measurements you need to have at least one Netrounds Test Agent installed. If you haven't already done the installation, consult our quick start guides for various types of Test Agents in the section Netrounds Test Agents.

Create a new test or monitoring and fill in the mandatory parameters below:

Parameters

Tests only

  • Duration (seconds): The duration of this test step in seconds. Min: 30 s. Max: 604800 s. Default: 60 s.
  • Fail threshold (seconds): The maximum number of errored seconds (ES) that may occur without triggering a fail for this test step. Default: 0.
  • Wait for ready: Time to wait before starting the test. The purpose of inserting a wait is to allow all Test Agents time to come online and acquire good time sync. Min: 1 min. Max: 24 hours. Default: "Don't wait", i.e. zero wait time.

General

  • Clients: Specify the Test Agents you want to use as clients in the test or monitoring. Clients can be located behind NAT.
  • Hosts: Hosts to ping: one or many, separated by commas. A host is a computer with an IP address.
  • Time between requests: The time to wait between two consecutive Ping requests. Min: 0.01 s. Max: 3600 s. Default: 10 s.

Threshold for errored seconds (ES)

  • Timeout (ms): Maximum tolerated Ping delay. If this value is exceeded, an errored second will be triggered. Min: 1 ms. Max: 30000 ms. Default: 1000 ms.

Advanced

  • Request lifetime (ms): The maximum time Netrounds will wait for a Ping response before the Ping request is canceled. Min: 1 ms. Max: 30000 ms. Default: 2000 ms.
  • TTL: Time To Live, the number of router hops an ICMP packet is allowed to traverse through the IP network before it is discarded by a router. For each router hop, the TTL value is decremented by one, and when TTL reaches zero, the IP packet is discarded. For Windows XP hosts, TTL is typically 128. Max: 255. Default: 64. Wikipedia description of TTL.
  • Payload (bytes): The number of bytes carried in the ICMP packet payload. Min: 0 bytes. Max: 65000 bytes. Default: 56 bytes.
  • DSCP/IPP: The Differentiated Services Code Point (DSCP) or IP Precedence to be used in IP packet headers. Default: "0/ IPP 0".
  • Path trace: Enable path tracing (hop-by-hop Ping). With this option set to Yes, only a single destination host can be entered, but all nodes along the path to the destination host will be monitored with Ping messages. No default.
  • Protocol: Network protocol to use for sending Ping packets: ICMP or UDP. The default is ICMP.
  • Delayed start (s): (Tests only) Time by which to delay the start of the test within a test step. Default: 0 s.

SLA thresholds (monitorings only)

  • SLA Good: Threshold for good fulfillment of service level agreement. Default: 99.95%.
  • SLA Acceptable: Threshold for acceptable fulfillment of service level agreement. Default: 99.5%.

Result metrics

  • Response time average (ms): Average Ping response time during the selected time period.
  • Response time min (ms): Minimum Ping response time.
  • Response time max (ms): Maximum Ping response time.
  • Loss (%): Percentage of Ping packets lost.
  • ES loss: Number of errored seconds triggered by excessive Ping packet loss.
  • ES timeout: Number of errored seconds triggered because the Timeout (Ping delay) threshold was exceeded.
  • ES response: Number of errored seconds triggered because sent and received ICMP data did not match, or because the expected ICMP reply was not received (for example, if Time-To-Live [TTL] expired and the ICMP packet was dropped by a router).
  • ES total: Aggregated errored seconds, taking into account all types of error.
  • SLA: Service level agreement fulfillment for the test or monitoring: equal to (100 – ES total) %.

Path tracing (Hop-by-hop Ping)

By enabling Path trace in the Advanced options, you turn the Ping testing feature into an advanced tool for localization of problematic network segments.

The Test Agent will first determine the path to the destination host using traceroute based on UDP. Once all the nodes in the path are known, the Test Agent will start sending ICMP Ping to monitor the round-trip time towards each node. On the result pages, the nodes are shown in the same order as they come in the path. No results are shown until the path tracing has completed, which may take 30–40 seconds longer.

  • Click a node to view results for each individual hop: ES total, minimum/average/maximum response time, and loss. Losses are currently only reported here.

  • Click Report to generate a report.

UDP Echo

Below is an example of a UDP Echo test. The test is set up by selecting UDP as Ping protocol.

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