Network Tests

This category of tests measures the network performance and path between an agent and a target device.

Network test types include

• Agent-to-server tests

• Agent-to-agent tests

Select any combination of Cloud and Enterprise Agents and a target URL or IP address. ThousandEyes sends lightweight bursts of TCP or ICMP traffic from agents to the target to measure loss, latency, and jitter. When you have agents on both ends, you can also run network tests between them that use UDP.

Both agent-to-server and agent-to-agent test types contain two views. The Overview view shows data on packet loss, latency, jitter (the mean deviation of the latency), path MTU, (agent-to-server and Enterprise Agents only) bandwidth and (agent-to-agent only) throughput. The Path Visualization view is a traceroute-like map of each router in the path from agent to target. For more information about views, see Views. For more information about path visualization, see Path Visualization.

Agent-to-Server Tests

An agent-to-server test measures network performance as seen from ThousandEyes agent(s) towards a remote server. The target could either be an IP address or a hostname. Measurements in an agent-to-server test combine parameters of both, forward and reverse paths. To measure direction-specific parameters an agent-to-agent test can be utilized.

Use Cases for Agent-to-Server Tests

• Measuring network performance when accessing the target remote server from agents assigned to test.

• Understand network path changes between source to destination.

• Verification of target availability.

• Identify network degradation along the network path.

• Verify network management of DSCP, MTU, and optimization.

• Monitor ingress traffic load distribution across ISPs.

Agent-to-Server Metrics

• Availability (%): Percentage of successful connections to the target.

• Response Time (ms): Total time to establish a connection and receive a response.

• Loss (%): Percentage of packets lost during transmission.

• Latency (ms): Round-trip time for packets to reach the target and return.

• Jitter (ms): Variation in latency between packets.

• Throughput (bps, Kbps, Mbps): Data transfer rate (for TCP-based tests).

• Error Details: Specific errors encountered (e.g., timeout, connection refused).

• Path Trace: Hops, IP addresses, and latency per hop in the network path.

Agent-to-Server Views

• Timeline (Agent-to-Server Layer): provides data on packet loss, latency, jitter (the mean deviation of the latency), path MTU and (Enterprise Agents only) bandwidth.

• Map

• Path Visualization: displays a router-by-router view of the nodes in the path from the agents to the target, along with IP, MPLS and routing information about each node and link between nodes.

Below is the Path Visualization for a test targeting google.com. Restricted access to Google results in 100% packet loss from Cloud Agent Beijing, China (China Unicom). The red circles signify nodes with forwarding loss. Hovering over a specific node will provide a modal with detailed information.

For more information about the Agent-to-Server layer, see Using the Network View.

Other Included Tests

• BGP test

Manually Configuring Agent-to-Server Tests

To configure an Agent-to-Server test:

1. In the ThousandEyes platform, navigate to Network & Synthetics > Test Settings.

2. Click the + button in the upper right corner of the screen.

3. Under the Network Tests section, select the card titled Network Discovery and Performance.

The configuration page is divided into three sections: Basic Settings, Network Settings, and Optional Settings.

Agent-to-Server Test Basic Settings

Agent-to-Server Test Network Settings

Agent-to-Server Test Optional Settings

Agent-to-Agent Tests

An agent-to-agent test evaluates the performance of the underlying network between two physical sites. The source and target for performing measurements here are ThousandEyes agents and can be both a Cloud Agent, an Enterprise Agent or a combination of both. For more information, see the agent-to-agent test overview.

Use Cases for Agent-to-Agent Tests

• Measure bi-directional network throughput.

• Measuring network connectivity characteristics between:

  • Multiple data centers.

  • Regional branch offices connecting to data centers.

  • Regional branch offices connecting to IAAS cloud environments.

  • Data centers connecting to IAAS environments.

• Branch office to HQ network quality via VPN and so on.

• Detect packet dropping network nodes on the path between source to destination.

• Evaluating the return path by performing bi-directional testing. Measure network performance and throughput between locations.

• Compare end-to-end network performance and characteristics between the forwarding and return paths.

• Measuring network characteristics between data centers, offices, and cloud environments.

• Evaluate network connections for specific applications.

• Detect latency and loss along the network path.

Agent-to-Agent Metrics

• Loss (%): Packet loss percentage in each direction.

• Latency (ms): Round-trip time or one-way latency (if agents are clock-synced).

• Jitter (ms): Variation in latency.

• Throughput (bps, Kbps, Mbps): Data transfer rate between agents.

• Bandwidth (bps, Kbps, Mbps): Measured or estimated throughput.

• Path MTU (bytes): Maximum Transmission Unit size along the path.

• Path Trace: Hops, IP addresses, and latency per hop.

• Error Details: Specific errors (e.g., packet drops, routing issues).

Agent-to-Agent Views

• Timeline (Agent-to-Agent layer): provides data on packet loss, latency, jitter (the mean deviation of the latency), and throughput.

• Map

• Path Visualization: displays router-by-router view of the nodes in the path from the agents to the target, along with IP, MPLS and routing information about each node and link between nodes. Arrows indicated direction of packet through the intermediate nodes.

The agent-to-agent test below depicts a connection error between Cloud Agent Wellington, New Zealand and Cloud Agent Johannesburg, South Africa.

For more information about Agent-to-Agent views, see Using the Network View.

Other Included Tests

• BGP test

Manually Configuring Agent-to-Agent Tests

• Test Type: agent-to-server or agent-to-agent.

• Test Name: This optional parameter gives the test a label. When no label is provided, then the values in the Target and (if the Protocol is TCP) the Port fields will be combined to comprise the Test Name. A test name cannot exceed 255 characters.

• Interval: How frequently the test will be run.

• Alerts: When the Enable box is checked, the Alert Rules and Alert Suppression Windows selected in their respective drop-down list will be active for the test. You can create, modify and delete Alert Rules with the Edit Alert Rules link.

Agent-to-Agent Test Basic Configuration

• Target Agent: Select a ThousandEyes Enterprise Agent available to your account.

• Agents: ThousandEyes Enterprise Agents agents that are available to your account. Select one or more Agents to assign them to this test.

• Direction: Select the direction of network and (optionally) throughput measurements between Agents as follows:

  • Source to Target: All selected agents will perform network measurements to Target Agent.

  • Target to Source: Target Agent will perform network measurements to each agent selected under the Agents tab.

  • Both Directions: Network measurements are performed from each selected Agent to Target Agent and from Target Agent to each selected Agent.

• Protocol: The protocol used when sending packets to the target.

• Enable Throughput: Check this box to perform throughput measurements in selected direction.

  • Duration: Use the slider to set time period for throughput measurements.

  • Simultaneous Connections (TCP only): Number of connections for each Source Agent to make to the Target Agent.

  • Maximum Rate (UDP only): Agents send packet for set duration as fast as possible.

  • Specified Rate (UDP only): Input sending rate of throughput packets.

  NOTE: It's not recommended to run tests on any agent installed on a routing or switching device due to common load, resource limitations, and the resource requirements of ThousandEyes bandwidth and throughput tests.

• Path Trace Mode: When the In Session checkbox is selected, perform a path trace "in session" within an agent to agent test, by initiating a TCP session with the target server, and sending path trace packets within that session. NOTE: This option is available to accommodate customer environments where middleboxes like Palo Alto and Juniper firewalls interfere with the way the ThousandEyes platform collects path trace metrics. These products misinterpret the path tracing as malicious probes, so by first establishing the TCP session the firewall doesn't reject path trace packets.

• Alerts: Check the Enable box to assign Alert Rules and create suppression windows.

Agent-to-Agent Test Advanced Configuration

• Server Port: The port number on the Target Agent to which agents send packets.

• MSS: Set the Maximum Segment Size to Auto or Manually specifying the number in bytes to avoid fragmentation. The range of manual sizes that will be accepted as valid to create or save this setting in a test is between 30-1400 bytes.

• Collect BGP data: Check this box to enable the BGP Path Visualization view.The BGP Public Monitors option button allows you to choose whether ThousandEyes' public BGP Monitors should be used for monitoring target prefixes. The Private BGP Monitors drop-down box allows you to select which private BGP Monitors should be used for monitoring target prefixes. By default, all public and private monitors are selected.

  Note that some monitors are IPv4 monitors and some are IPv6 monitors. Tests with IPv4 targets will display only IPv4 monitors in the BGP Path Visualization; similarly, tests with IPv6 targets display only IPv6 monitors in the BGP Path Visualization.

• Transmission Rate: Select the checkbox to “Enforce fixed packet rate”. This will reveal a slider bar that offers the option to reduce rate packets are sent to measure the network in packets per second.

• No. of Path Traces: Three path trace packets are used by each agent by default to discover each hop in the Path Visualization to the target. Uncheck the box to display a slider which allows selection of 1 - 10 packets. To learn more about path trace, see Getting Started with Path Visualization.

• Payload Size: Size of the packets for network and (optionally) throughput measurements:

  • Auto: Packet size is determined based on Path MTU

  • Manual: Packet size is IP header size + TCP or UDP header size + <input value> bytes.

• DSCP selector: Set the Differentiated Services Code Point (DSCP) field of the IP header for probe packets, in order for the packets to be handled by quality-of-service (QoS) devices. The default value is DSCP=0 (best effort).

Using the Agent Selector

Use agent selector to quickly select all cloud agents from a particular provider or region and see their global distribution on a map, filtering by IP and custom labels to refine your results. With the advanced view, you can use custom filters, compare locations, and select specific agents based on detailed attributes presented in a table view with customizable columns.

With the agent selector, you can:

• Select Enterprise Agents or Cloud Agents tabs

• Group by labels or provider

• Filter on IP Support or Countries

For a table view with customizable columns and custom filters, select the Advanced toggle at the upper right of the screen.