A dual-ended path is one that is monitored independently in each direction. For this, the path requires a monitoring point at each end. Monitoring in both directions is particularly important for paths that have asymmetric loads (for example, video conferencing or a typical ISP connection) because capacity measurements using single-ended monitoring can only measure the slower of the two directions. With dual-ended monitoring, capacity can be measured in each direction independently.

Characteristics of dual-ended paths include:

  • they require monitoring points at both ends
  • they use UDP in addition to ICMP
  • the path performance page displays one chart for each direction
    • exceptions are the Latency and Round-Trip Time charts as they already account for two directions
  • there are some restrictions when running diagnostics

Create a dual-ended network path

In order to create a dual-ended path, the path source and the path target must both be monitoring points. The source must be an Enterprise Monitoring Point (EMP). The target can be an EMP or an AppNeta WAN Target.

To create a dual-ended path between two monitoring points:

  1. Navigate to Delivery > Network Path List.
  2. Click + Add Network Path.
    • The Path Setup Wizard starts.
  3. In Step 1, select a source monitoring point.
  4. Click Next.
  5. In Step 2, select Choose Targets, specify the target and its location.
  6. Click Next.
  7. In Step 3, in the Group drop-down, select the group to add the path to.
  8. In the Dual-Ended Path field, select Set to Dual Ended Path if possible.
  9. Click Next.
  10. In Step 4, review the path parameters.
  11. Click Add Network Paths.
    • The dual-ended network path is created in the group specified.

Create a dual-ended network path from a single-ended path

You can create a dual-ended network path from a single-ended path, but the existing path source and the path target must both be monitoring points.

To create a dual-ended path from a single-ended path:

  1. Navigate to Delivery > Network Path List.
  2. Next to the single-ended path you want to modify, navigate to 50x50_trans.png > Configure.
  3. Click Create this path with dual-ended instrumentation.
  4. Update the path name (optional).
  5. Click Submit.
    • A dual-ended network path is created and the single-ended path still exists.

Customize the UDP port range

Specifying the port range used for dual-ended paths allows you to monitor engineered traffic patterns. Using a custom, narrow port range, enables network administrators to classify UDP probes between the source and target using extended ACLs so that the probes can be influenced by policy-based QoS, policy-based routing, and port-based traffic filtering.

To customize the UDP port range:

  1. Log in to Web Admin.
  2. Navigate to Appliance Configuration > Sequencer Configuration.
  3. Uncommenting the line “# UDP Port Range: 45056,49151”.
  4. Change the port range.
  5. Click Save.
  6. Click OK to restart the sequencer process.
    • The updated UDP port range is active.

Configure a dual-ended path to use a non-default return path for diagnostics

When a dual-ended path is defined using the default interfaces on both the source and the target monitoring points, the target monitoring point knows how to create a return path to the source based on information provided by APM. If you need to use interfaces on the source or target other than the defaults, a separate configuration is required as this information is not available to APM.

Configuring a non-default return path also requires that both the source and target monitoring points need to be Enterprise Monitoring Points that you control. They cannot be AppNeta WAN Targets.

To specify a non-default return path for diagnostics, you need to use the APM API.

  1. Log in to APM.
  2. Confirm you are using the correct organization.
    • The organization name appears under your name on the top right. If you need to change it:
      1. Click your name.
      2. Click Change Organization.
      3. Select your organization in the dropdown.
      4. Click Change.
  3. Navigate to > API.
  4. Get the organization ID.
    1. Navigate to organization > GET /v3/organization.
    2. Click Try it out!
    3. In the Response Body section, find your organization name in a displayName field.
    4. The organization ID is in the associated id field. Record it.
  5. Get the path ID.
    1. Navigate to path > GET /v3/path.
    2. In the orgId field of the Parameters section, enter the organization ID.
    3. In the sourceAppliance field, of the Parameters section, enter the source monitoring point name.
    4. Click Try it out!
    5. In the Response Body section, find the path you are using in a pathName field.
    6. The path ID is in the associated id field. Record it.
  6. Get the target appliance ID.
    1. Navigate to appliance > GET /v3/appliance.
    2. In the orgId field of the Parameters section, enter the organization ID.
    3. Click Try it out!
    4. In the Response Body section, find the target monitoring point name in a name field.
    5. The appliance ID is in the associated id field. Record it.
  7. Get the target appliance interface to use for the return path.
    1. Navigate to appliance > GET /v3/appliance/{id}.
    2. In the id field of the Parameters section, enter the target appliance ID.
    3. Click Try it out!
    4. In the Response Body section, find the interface to use for the return path in the localNetworkInterfaces field. Record it. Make sure to record the full string inside the double quotes.
  8. Get the IP address or hostname of the source monitoring point to use as the target of the return path.
    • If the source and target devices are separated by a public network, use the public IP address or hostname of the interface on the source monitoring point you want the return path targeted to. Otherwise, use the private IP address or hostname of that interface.
  9. Set up the return path using the information gathered.
    1. If you are creating the reverse path for the first time:
      • Navigate to path > POST /v3/path/{id}/diagnosticSettings.
    2. If you are updating an existing configuration:
      • Navigate to path > PUT /v3/path/{id}/diagnosticSettings.
    3. Within the Parameters section, do the following:
      1. In the Id field, enter the path ID recorded above.
      2. In the body section, click the Model Schema on the right.
        • The text is copied to the body field.
      3. Edit the text in the body field as follows:
        1. Set pathId to the path ID recorded above.
        2. Set the targetApplianceID to the target appliance ID recorded above.
        3. Set the returnPathApplianceInterface to the target appliance interface recorded above.
        4. Set the returnPathTargetAddress to the source monitoring point IP address or hostname recorded above.
    4. Click Try it out!
    5. Confirm that the configuration change was made successfully.
      • The Response Body section should contain the values you entered.
      • The Response Code should be 200.