Manual Chapter : Digital Diagnostics Monitoring \(DDM\)
back-action F5 Platforms: Essentials

Updated Date: 05/29/2026

Digital Diagnostics Monitoring \(DDM\)

Digital Diagnostics Monitoring (DDM) is a feature used in optical transceiver modules that enables you to view real-time information about transceivers, such as optical output and input power.

For information about which F5 transceiver modules support DDM, see F5 Platforms: Accessories.

Digital Diagnostics Monitoring (DDM) is available for transceiver modules that support DDM on these platforms.

The platform must be running BIG-IP software version 12.1.0 or later.

  • BIG-IP 5000 Series
  • BIG-IP 6900 Series
  • BIG-IP 7000 Series
  • BIG-IP 8900 Series
  • BIG-IP 10000 Series
  • BIG-IP 11000 Series
  • BIG-IP 12000 Series

The platform must be running BIG-IP software version 12.1.0 or later.

  • VIPRION B2100
  • VIPRION B2150
  • VIPRION B2250
  • VIPRION B4300
  • VIPRION B4450

The platform must be running F5OS software version 1.0.0 or later.

  • VELOS BX110

The transceiver modules supply optical power in units of .1 uWatts. Per SFF-8472, the measured Tx and Rx power is in mW. The power is provided as a 16 bit unsigned integer with the power defined as the full 16 bit value (0-65535) with LSB equal to 0.1uW, yielding a total range of 0 to 6.5535 mW (~ -40 to +8.2 dBm).

Most displays of optical power are in dBm (decibels/milliwatts). Decibels is a ratio of two power levels, one of which is considered the reference value. The db is a logarithmic scale. The m in dBm refers to the reference power which is 1 milliwatt.

To convert between the raw hardware readings of .1 uWatts and dBm, use this formula:

10 * log10f(raw_power/10000.0)

On BIG-IP/VIPRION systems, before you can use Digital Diagnostics Monitoring (DDM) features, you have to enable DDM on the system. After it is enabled, you can view DDM information for installed and supported optical transceiver modules.

You can use the TMOS Shell (tmsh) to enable Digital Diagnostics Monitoring (DDM) information about interfaces in your system. DDM is disabled by default.

  1. Connect to the system using the serial console or by opening an SSH session to the management IP address.

  2. Log in to the command line interface (CLI) of the system using an account with root access.

  3. Enable DDM.

    tmsh modify sys db ddm.bcm56xxd.enable value <enable | disable>

You can use the TMOS Shell (tmsh) to verify whether Digital Diagnostics Monitoring (DDM) is enabled.

  1. Connect to the system using the serial console or by opening an SSH session to the management IP address.

  2. Log in to the command line interface (CLI) of the system using an account with root access.

  3. View the state of DDM on the system.

    tmsh list sys db ddm.bcm56xxd.enable

    This is an example of the output that you might see when you run this command, and DDM is enabled:

    sys db ddm.bcm56xxd.enable {
    value "enable"
}

You can use the TMOS Shell (tmsh) to view Digital Diagnostics Monitoring (DDM) information about optical transceiver modules installed in your system.

  1. Connect to the system using the serial console or by opening an SSH session to the management IP address.

  2. Log in to the command line interface (CLI) of the system using an account with root access.

  3. View DDM information for an interface.

    tmsh show net interface-ddm <interface-key>

    This command sequence always shows four power levels. For 40GbE and 100GbE, all four power levels are filled. 10GbE interfaces only transmit and receive one power level. For 10GbE interface, you can ignore the other lanes, which contain 0mW and -1000000dBm. These indicate invalid or no readings. Only the first values are valid.

    Note: If you do not specify an <interface-key>, you see information for all interfaces.

    This is an example of the output that you might see when you run this command on interface 2.6, a four lane 40GbE transceiver that reports four lanes of DDM information (note that power values are within power thresholds, so all alarms and warnings are false):

    ---------------------------------------------------------------
Digital Diagnostic Monitoring Interface:2.6
Laser Transmit and Receive Power Value
Transmit Power1                    1.3242mW    1.22dBm
Transmit Power2                    1.1495mW    0.61dBm
Transmit Power3                    1.0103mW    0.04dBm
Transmit Power4                    1.1381mW    0.56dBm
Receive Power1                     1.2567mW    0.99dBm
Receive Power2                     1.2439mW    0.95dBm
Receive Power3                     1.4072mW    1.48dBm
Receive Power4                     1.3279mW    1.23dBm
Transmit and Receive Power Thresholds
Transmit Low Alarm Threshold       0.0794mW  -10.99dBm
Transmit High Alarm Threshold      3.3884mW    5.30dBm
Transmit Low Warning Threshold     0.1995mW   -6.99dBm
Transmit High Warning Threshold    1.9953mW    3.00dBm
Receive Low Alarm Threshold        0.0170mW  -17.69dBm
Receive High Alarm Threshold       2.1380mW    3.30dBm
Receive Low Warning Threshold      0.0427mW  -13.69dBm
Receive High Warning Threshold     1.6982mW    2.30dBm
Transmit Low Alarm               false
Transmit High Alarm              false
Receive Low Alarm                false
Receive High Alarm               false
Transmit Low Warning             false
Transmit Hi Warning              false
Receive Low Warning              false
Receive High Warning             false

You can see messages specific to Digital Diagnostics Monitoring (DDM) in the /var/log/ltm log file.

  1. Connect to the system using the serial console or by opening an SSH session to the management IP address.

  2. Log in to the command line interface (CLI) of the system using an account with root access.

  3. Use grep to search the log for messages that are specific to DDM.

    zgrep -i ddm /var/log/ltm*

For the Digital Diagnostic Monitoring (DDM) capability available on F5 platforms, you can use the industry-standard System Management Network Protocol (SNMP) protocol to read information collected from optical transceiver modules, when available. This information is in BIG-IP Core Statistics. You can then use SNMP and the F5-BIG-IP-SYSTEM-MIB file to access this information.

When you use SNMP to access the information that DDM collects, note this F5 DDM behavior:

  • F5 interface rows are indexed by interface name.
  • Information in the F5-BIG-IP-SYSTEM-MIB file is read-only. SNMP objects cannot modify or configure DDM information.
  • SNMP can monitor all transceivers that support DDM.
  • The thresholds that SNMP monitors are the vendor-specified thresholds read from the transceivers.
  • The F5 MIB file monitors optical receive and transmit level power.
  • If a threshold is exceeded, the F5 DDM notification message contains the value that exceeded the threshold.
  • SNMP sends traps when a DDM-monitored transmit or receive power reading crosses a warning or alarm threshold.

For more information about setting up SNMP monitoring, see External Monitoring of BIG-IP Systems: Implementations at support.f5.com.

You can use the TMOS Shell (tmsh) to configure your BIG-IP system to allow SNMP access from remote hosts.

  1. Connect to the system using the serial console or by opening an SSH session to the management IP address.

  2. Log in to the command line interface (CLI) of the system using an account with root access.

  3. Configure the default entry to allow access from specified hosts.

    tmsh modify sys snmp allowed-addresses replace-all-with { <*IP-addresses-or-IP-address-range*> }

You can use the industry-standard System Management Network Protocol (SNMP) to monitor information that Digital Diagnostic Monitoring (DDM) collects about optical transceiver modules from a remote host.

  1. Log in to the command-line interface of the remote host.

  2. Read the information using SNMP.

    This example collects data about laser optical output power, where public is the community name and bigip is the host name of the BIG-IP system: snmpget -c public <bigip> sysSwitchDdmStatTxPwr1.

  3. Configure SNMP to receive notifications using tmsh:

    1. Connect to your BIG-IP system using the serial console or by opening an SSH session to the management IP address.

    2. Log in to the command-line interface (CLI) of the system using an account with root access.

    3. Configure your BIG-IP system to add an SNMP trap receiver.

      The BIG-IP system sends trap notifications to the designated trap receiver.

      This example adds an SNMP version 2c trap named tv2, to the system, where <trap-receiver-IP-address> is the destination IP address of tv2, the port is 162, and where <community-string> is the community that has access to tv2.

      tmsh modify sys snmp traps add {tv2 {version 2c community <*community-string*> host <*trap-receiver-IP-address*> port 162}}

On VELOS systems, Digital Diagnostics Monitoring (DDM) features are enabled by default on all port groups with optical transceiver modules inserted in the port.

You can use the CLI to view Digital Diagnostics Monitoring (DDM) information for port groups on your chassis partition.

  1. Log in to the command line interface (CLI) of the chassis partition using an account with admin access.

    When you log in to the system, you are in user (operational) mode.

  2. View all DDM information for a specified port group.

    show portgroups portgroup <*blade-number*>/<*interface-number*> state ddm

    This command sequence always shows four power levels. For 40GbE and 100GbE, all four power levels are filled. 10GbE interfaces only transmit and receive one power level. For 10GbE interface, you can ignore the other lanes, which contain 0mW and -1000000dBm. These indicate invalid or no readings. Only the first values are valid.

    Note: If you do not specify a port group (or blade/interface pair), you see information for all port groups.

    This is an example of the output that you might see when you run this command on port group 2/1, a four lane 100GbE transceiver that reports four lanes of DDM information (note that power values are within power thresholds, so all alarms and warnings are false):

    default-1# show portgroups portgroup 2/1 state ddm
						state ddm rx-pwr low-threshold alarm -14.0
						state ddm rx-pwr low-threshold warn -11.0
						state ddm rx-pwr instant val-lane1 2.19
						state ddm rx-pwr instant val-lane2 2.27
						state ddm rx-pwr instant val-lane3 2.14
						state ddm rx-pwr instant val-lane4 2.24
						state ddm rx-pwr high-threshold alarm 3.4
						state ddm rx-pwr high-threshold warn 2.4
						state ddm tx-pwr low-threshold alarm -10.0
						state ddm tx-pwr low-threshold warn -8.0
						state ddm tx-pwr instant val-lane1 0.06
						state ddm tx-pwr instant val-lane2 -0.37
						state ddm tx-pwr instant val-lane3 -0.14
						state ddm tx-pwr instant val-lane4 -0.18
						state ddm tx-pwr high-threshold alarm 5.0
						state ddm tx-pwr high-threshold warn 3.0
						state ddm temp low-threshold alarm -5.0
						state ddm temp low-threshold warn 0.0
						state ddm temp instant val 35.5898
						state ddm temp high-threshold alarm 75.0
						state ddm temp high-threshold warn 70.0
						state ddm bias low-threshold alarm 0.003
						state ddm bias low-threshold warn 0.005
						state ddm bias instant val-lane1 0.007576
						state ddm bias instant val-lane2 0.007536
						state ddm bias instant val-lane3 0.007494
						state ddm bias instant val-lane4 0.00752
						state ddm bias high-threshold alarm 0.013
						state ddm bias high-threshold warn 0.011
						state ddm vcc low-threshold alarm 2.97
						state ddm vcc low-threshold warn 3.135
						state ddm vcc instant val 3.2576
						state ddm vcc high-threshold alarm 3.63
						state ddm vcc high-threshold warn 3.465

  3. You can run the show portgroups portgroup <port-group> state ddm command to view information about only a specific option for a specified port group.

    Available options include:

    Option Description
    bias Display the magnitude of transceiver laser bias current, in amperes (Amps).
    displaylevel Limit how many levels are displayed by the show command. Specify 1 to show only the direct children of an element. If you specify 3, then only elements at depth 3 below a given element will be displayed, etc. The range is from 1 through 64.
    rx-pwr Display the transceiver laser rx (receive) optical power, in decibel/milliwatts (dBm).
    temp Display the transceiver temperature, in Celsius.
    tx-pwr Display the transceiver tx (transmit) optical power, in decibel/milliwatts (dBm).
    vcc Display transceiver internally measured supply voltage bias, in Volts.

You can use the command-line interface (CLI) to disable Digital Diagnostics Monitoring (DDM) collection on a specific port group on a VELOS blade. DDM is enabled by default to poll the optical transceivers every 30 seconds.

  1. Log in to the command line interface (CLI) of the chassis partition using an account with admin access.

    When you log in to the system, you are in user (operational) mode.

  2. Disable DDM polling on a specified port group by setting the value for polling to 0 (zero) seconds.

    portgroups portgroup <*blade-number*>/<*interface-number*> config ddm ddm-poll-frequency 0

    This example disables polling on portgroup 2/1 by setting the value for polling to 0 :

    portgroups portgroup 2/1 config ddm ddm-poll-frequency 0

You can see messages specific to Digital Diagnostics Monitoring (DDM) in the log/velos.log file.

  1. Connect to the system using a management console or console server.

    Note: The default baud rate and serial port configuration is 19200/8-N-1.

  2. Log in to the command line interface (CLI) of the system controller using an account with root access.

  3. Use grep to search the log for messages that are specific to DDM.

    zgrep -i ddm log/velos.log