--- title: "Two-Way Active Measurement Protocol (TWAMP) Overview" slug: "using-the-two-way-active-measurement-protocol-twamp" tags: ["TWAMP", "reflector ", "Actuator", "statistics", "sensor control ", "Assurance Sensor Control"] updated: 2026-07-07T13:46:10Z published: 2026-04-14T18:10:16Z canonical: "docs.crossworkassurance.cisco.com/using-the-two-way-active-measurement-protocol-twamp" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.crossworkassurance.cisco.com/llms.txt > Use this file to discover all available pages before exploring further. # Two-Way Active Measurement Protocol (TWAMP) Overview Use the Two-Way Active Measurement Protocol (TWAMP) to measure round-trip IP performance between any two TWAMP-enabled units deployed in a network. With TWAMP, you can reliably perform in-band, roundtrip performance measurements and identify performance issues by sending test packets to a unit that reflects them back. With TWAMP packet generation, you can perform one- and two-way delay and delay variation in a Layer-3 network, and measure packet loss. The Cisco® Crosswork Assurance Sensor Control allows TWAMP packets to be reflected through its linked remote devices. TWAMP defines two protocols: - TWAMP control protocol - TWAMP test protocol TWAMP light only includes the test protocol and is supported by the remote devices’ TWAMP reflection feature. When using TWAMP light, test sessions can be configured without the control protocol. **Note**: This function is only to be used with TWAMP when connecting to Layer-3 TWAMP session sender devices. ## Setting Up TWAMP Control Behavior TWAMP control protocols include: - Alarm indicating an issue with TWAMP control protocol: Error information is transferred to the result record if the user is disconnected from the twampcontrol server and a progress/state XML message is sent to sensor orchestration capabilities within Crosswork Assurance. - TWAMP UDP data continues when TWAMP control protocol stops. - On TWAMP session startup, the session goes into a waiting state if it cannot connect and keeps trying to establish the session. - TWAMP packet loss alarm continues to be present even if the TWAMP control protocol is down. **CAUTION**: This feature is not enabled by default. **▶ To enable this feature using the CLI, enter:** ``` agent-server { disable } ``` **CAUTION**: Disabling this will stop your running sessions. ``` pm-tools twamp-cp-continuous { enable } pm-tools twamp-cp-continuous {show } agent-server { enable } ``` ## Setting Up a TWAMP Reflector The Sensor Control can be configured to reflect TWAMP packets through the remote devices linked to it. The following procedure shows how to enable this kind of packet reflection. ### Displaying a Summary of TWAMP Sessions **▶ To display a summary of TWAMP sessions (stateless and stateful)** 1. Access the page **SOAM ▶ TWAMP ▶ Reflector ▶ Configuration**. A list of all TWAMP reflection instances displays, divided into these sections: **TWAMP Stateless summary**, **TWAMP Stateful default filter summary** and **TWAMP Stateful summary**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. 2. (Optional) Limit the view to only certain sessions. Pick from the options in the **Filter** dropdown list, enter a value, and then click **Search**. ***Tip:** Enter an asterisk ( * ) as a wildcard to replace one or more characters.* ### Editing TWAMP Stateless Sessions **▶ To edit a TWAMP stateless session** 1. In the **Device** column of **TWAMP Stateless summary**, click the session you want to edit. The **TWAMP stateless configuration** form displays. 2. Edit the fields as required, then click **Apply**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### Editing TWAMP Stateful Default Filters **▶ To edit a TWAMP Stateful default filter** 1. In the **Device** column of **TWAMP Statateful default filter summary**, click the filter you want to edit. The **TWAMP stateful default filter** form displays. 2. Edit the fields as required, then click **Apply**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### Adding TWAMP Stateful Sessions **▶ To add a TWAMP stateful session** 1. Click **Add** below **TWAMP Stateful summary**. The **New TWAMP stateful configuration** form displays. 2. Complete the parameters, then click **Apply**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### Editing TWAMP Stateful Sessions **▶ To edit a TWAMP stateful session** 1. In the **Session** column of **TWAMP Stateful summary**, click the session you want to edit. The **TWAMP Stateful configuration** form displays. 2. Edit the fields as required, then click **Apply**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### Deleting TWAMP Stateful Sessions **▶ To delete a TWAMP stateful session** 1. In the **Session** column of **TWAMP Stateful summary**, click the session you want to delete. The **TWAMP Stateful configuration** form displays. 2. Click **Delete**. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### Configuring NFV TWAMP Stateful Reflections **▶ To configure NFV TWAMP stateful reflection** 1. In the **Session** column of **TWAMP Stateful summary**, click the session you want to configure. The **TWAMP Stateful configuration** form displays. **Note**: The TWAMP session to be reflected in NFV must use a different UDP port than the TWAMP stateless reflection on the device and should not match any TWAMP stateful reflection filter on the device. 2. Enable the TWAMP reflection in sensor control. The UDP port used by the session to be reflected must match the UDP configured in (**SOAM ▶ Software Generator/Reflector ▶ Reflector Configuration**). 3. Click **Apply**. **Note**: To be reflected in NFV, the TWAMP session destination must be a VCE IP address. See [TWAMP Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#twamp-reflector-configuration-parameters) for more information. ### TWAMP Reflector Configuration Parameters **TWAMP Configuration (SOAM ▶ TWAMP ▶ Reflector ▶ Configuration)** | Parameter | Description | | --- | --- | | Device | Name of the remote device on which the TWAMP reflection instance will be active. | | State | Displays whether the processing of TWAMP packets destined for a remote device is enabled or disabled. | | Enable | Select to enable the processing of TWAMP packets destined for a remote device. | | UDP Destination | UDP port on which TWAMP packets are to be reflected by the remote device. The default value is *862*. Other acceptable values are in the ranges of from *1* to *39999* and from *60001* to *65535*. | | IP Match | Select to enable the processing of TWAMP packets destined to a remote device. IP Match applies to IPv4 only. Automatically disabled for IPv6 frames. | | Op Status | TWAMP operational status code: - **link-down**: Remote device is unlinked - **waiting application**: Service is not available presently as Device is in TGEN - **programming**: Remote device is currently being programmed - **failed**: Remote device has encountered a failure - **active**: Remote device is active and fully functional - **inactive**: Feature is inactive | | Session | TWAMP stateful session number (1 to 16). | | Filter type | Filter type: IPv4, IPv6, DefaultIPv4, or DefaultIPv6. | | Filter Name | Unique name used to identify the filter. | ## Managing In-Use Software Generators/Reflectors Use the page **SOAM ▶ Software Generator/Reflector ▶ Session Status** to view details of current Actuator sessions, as well as a listing (or port map) of all ports associated with Actuator sessions that use Level-3 protocols (TCP, UDP). The total number of sessions and reflectors in use, and the maximum number of each, appear at the top of the page. ### Viewing the Status of Actuator Sessions **▶ To view the status of Actuator sessions** 1. Access the page **SOAM ▶ Software Generator/Reflector ▶ Session Status**. A listing of all Actuator sessions, along with summary details, display. 2. (Optional) Limit the view to only certain sessions. Pick from the options in the **Filter** dropdown list, enter a value, and then click **Search**. ***Tip:** Enter an asterisk ( * ) as a wildcard to replace one or more characters.* 3. Click a **Peer ID** value from the list to view additional information such as the packet rate and bandwidth. See [Actuator Session Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#actuator-session-parameters) for information. ### Actuator Session Parameters **Actuator Session Parameters (SOAM ▶ Software Generator/Reflector ▶ Session Status)** | Value | Description | | --- | --- | | PeerId | Unique value assigned to this peer | | State | Current state of this Actuator session: - **idle**: Stream is idle - **blocked**: Stream is blocked (disabled) - **waiting**: Stream is waiting - **stopped**: Stream is stopped - **running**: Stream is running - **error**: Stream is in error state - **pause**: Bandwidth stream is in pause state - **xmit**: Bandwidth stream is transmitting - **sync**: Bandwidth stream prepares transmitter | | Type | Actuator session type: - **2way**: 2xOneWay stream - **echo**: Echo stream - **twamp**: TWAMP Light (RFC-5357) - **ethlb**: ETH-LB (Y.1731/802.1ag) - **ethdm**: ETH-DM (Y.1731) - **ethvs**: ETH-VS (Y.1731) | | Encap | Encapsulation method used for the packets transmitted as part of this session, such as UDP/IPv4 | | SrcAddr | Source IP address of the session | | DstAddr | Destination IP address of the session | ### Viewing the Actuator Session Portmap Knowledge of all ports currently in use by all Actuator sessions can be helpful when configuring with a firewall or when using sensor orchestration capabilities within Crosswork Assurance’s auto-generate port feature to automatically assign port numbers. **Note**: As of Sensor Control 22.06, with the corresponding device firmware suite, you can have up to two TWAMP UDP ports for reflectors on Sensor Control that have UDP/IPv4 and UDP/IPV6 encapsulation. This feature is fully-supported starting with Skylight Orchestrator 22.10. Using Skylight Orchestrator 22.07 or older requires the creation of a reflector object: create a reflector endpoint in Skylight Orchestrator using the IP address of the interface you want to use as a reflector, then create TWAMP reflector sessions for multiple TWAMP UDP ports with the previously-created reflector endpoint. **▶ To view the Actuator session portmap** 1. Access the page **SOAM ▶ Software Generator/Reflector ▶ Session Status**. A listing of all ports Actuator sessions displays in the **Actuator Session Portmap** section. 2. (Optional) Limit the view to only certain sessions. Pick from the options in the **Filter** dropdown list, enter a value, and then click **Search**. ***Tip:** Enter an asterisk ( * ) as a wildcard to replace one or more characters.* See [Actuator Session Portmap Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#actuator-session-portmap-parameters) for information. ### Actuator Session Portmap Parameters **Actuator Session Portmap (SOAM ▶ Software Generator/Reflector ▶ Session Status)** | Value | Description | | --- | --- | | Protocol | Level-3 protocol used by this Actuator session, such as RTP, TCP, Y1731, GRE, SCTP, ICMP, UDP, dm, lb, vs, IPv4 or IPv6 | | Port | UDP or TCP port number used by this Actuator session | | Type | Actuator session type, such as stream or external | | Function | Label assigned to the protocol, such as 2xOneWay or TWAMP | ## Setting Up a Reflector Use the page **SOAM ▶ Software Generator/Reflector ▶ Reflector Configuration** to view a reflector’s current status, to enable or disable reflectors, and to change a reflector's assigned port number. **Notes**: Although you can manage reflectors via the Sensor Control, managing transceiver sessions must be carried out using the Skylight orchestrator module. As of Sensor Control 22.06, with the corresponding device firmware suite: - You can have up to two TWAMP UDP ports for reflectors on Sensor Control that have UDP/IPv4 and UDP/IPV6 encapsulation. This feature is fully-supported starting with Skylight Orchestrator 22.10. Using Skylight Orchestrator 22.07 or older requires the creation of a reflector object: create a reflector endpoint in Skylight Orchestrator using the IP address of the interface you want to use as a reflector, then create TWAMP reflector sessions for multiple TWAMP UDP ports with the previously-created reflector endpoint. - Encapsulation methods udp/ipv6 and icmp/ipv6 are supported. ### Configuring Reflectors You can enable or disable a reflector and change its assigned port number. CLI-level Configuration Some reflector capabilities require CLI‑level configuration and cannot be set through the Management Web Interface. For example, ETH‑OAM reflectors must have a MEG level and interface defined in the CLI using the `reflector enable eth-oam meg-level <value> interface <name>` command before reflection can operate correctly. Refer to the [reflector](/v1/docs/cli-sc-reflector) section of the CLI guide for complete command usage and parameters. **▶ To configure a reflector** 1. Access the page **SOAM ▶ Software Generator/Reflector ▶ Reflector Configuration**. A listing of all reflectors displays. 2. (Optional) Limit the view to only certain reflectors. Pick from the options in the **Filter** dropdown list, enter a value, and then click **Search**. ***Tip:** Enter an asterisk ( * ) as a wildcard to replace one or more characters.* 3. Click an **Index** value from the list. The **Reflector Configuration** form displays. 4. Complete the fields as required, then click **Apply**. See [Reflector Configuration Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#reflector-configuration-parameters) for information. ### Reflector Configuration Parameters **Reflector Parameters (SOAM ▶ Software Generator/Reflector ▶ Reflector Configuration)** **Reflector Status** | Value | Description | | --- | --- | | Index | Unique value assigned to this reflector | | State | Current state of this reflector: - **Free**: The reflector is not yet enabled or assigned to a port - **Idle**: The reflector is enabled, but not actively reflecting packets - **Running**: The reflector is enabled and actively reflecting packets - **Blocked**: The reflector is disabled and not actively reflecting packets | | Type | Reflector type: - 2way-rf - echo-rf - ethlb-rf - twamp-rf - ethdm-rf - ethvs-rf | | Encap | Encapsulation method used by this reflector, such as RTP, TCP, Y1731, GRE, SCTP, ICMP, UDP, dm, lb, vs, IPv4 or IPv6 | | Port | Port number currently assigned to this reflector | **Reflector Configuration** | Value | Description | | --- | --- | | Enable | Select to enable this reflector Once enabled, the port's state automatically changes to Idle ***Note**: The reflector must be assigned a valid port number before it can be enabled* | | State | Current state of this reflector, as described above | | Reflector Type | Reflector type, as described above | | Protocol | Protocol used by this reflector, such as RTP, TCP, Y1731, GRE, SCTP, ICMP, UDP, dm, lb, vs, IPv4 or IPv6 | | Port | Enter a port number to assign to this reflector | ## Viewing Software Generator/Reflector Session Statistics Use the page **SOAM ▶ Software Generator/Reflector ▶ Session Statistics** to display state information and configuration details of running generator/reflector sessions. **▶ To view software generator/reflector session statistics** 1. Access the page **SOAM ▶ Software Generator/Reflector ▶ Session Statistics**. Statistics for all generator/reflector sessions are provided in a grid. See [Session Statistics Parameters](/v1/docs/using-the-two-way-active-measurement-protocol-twamp#session-statistics-parameters) for information. 2. (Optional) Limit the view to only certain Actuator sessions. Pick from the options in the **Filter** dropdown list, enter a value, and then click **Search**. ***Tip:** Enter an asterisk ( * ) as a wildcard to replace one or more characters.* ### Session Statistics Parameters **Session Statistics (SOAM ▶ Software Generator/Reflector ▶ Session Statistics)** | Value | Description | | --- | --- | | PeerId | Session's unique 32-bit identifier | | State | Current state of the session: - **Free**: The reflector is not yet enabled or assigned to a port - **Idle**: The reflector is enabled, but not actively reflecting packets - **Running**: The reflector is enabled and actively reflecting packets - **Blocked**: The reflector is disabled and not actively reflecting packets | | Type | Session type: - 2way-rf - echo-rf - ethlb-rf - twamp-rf - ethdm-rf - ethvs-rf | | Encap | Encapsulation method used by this session, such as RTP, TCP, Y1731, GRE, SCTP, ICMP, UDP, dm, lb, vs, IPv4 or IPv6 | | TxPkts | Number of packets that have been transmitted since the session began | | RxPkts | Number of packets that have been received since the session began | | Errors | Number of errors that have been raised since the session began | | Syst Inf/Vce | Interface or VCE which is associated with Actuator sessions. 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