4.14.1 LLDP Settings

The LLDP Configuration page allows you to inspect and configure the current LLDP interface settings.

Figure 4-66. LLDP Configuration

The LLDP Configuration page has the following parameters:

  • LLDP Parameters
    • Tx Interval: The switch periodically transmits LLDP frames to its neighbors for having the network discovery information up to date. The interval between each LLDP frame is determined by the Tx Interval value. Valid values are restricted to 5:32768 seconds.
    • Tx Hold: Each LLDP frame contains information about how long time the information in the LLDP frame shall be considered valid. The LLDP information valid period is set to Tx Hold multiplied by Tx Interval seconds. Valid values are restricted to 2:10 times.
    • Tx Delay: If some configuration is changed (for example, the IP address) a new LLDP frame is transmitted, but the time between the LLDP frames is always at least the value of Tx Delay seconds. Tx Delay cannot be larger than ¼ of the Tx Interval value. Valid values are restricted to 1:8192 seconds.
    • Tx Reinet: When an interface is disabled, LLDP is disabled or the switch is rebooted, a LLDP shutdown frame is transmitted to the neighboring units, signaling that the LLDP information is not valid anymore. Tx Reinit controls the number of seconds between the shutdown frame and a new LLDP initialization. Valid values are restricted to 1:10 seconds.
  • LLDP Interface Configuration
    • Interface: The switch interface name of the logical LLDP interface
    • Mode: Select LLDP mode:
      • Rx Only: The switch does not send LLDP information but LLDP information from neighbor units is analyzed
      • Tx Only: The switch drops LLDP information received from neighbors but sends LLDP information
      • Disabled: The switch does not send LLDP information and drops LLDP information received from neighbors
      • Enabled: The switch sends LLDP information and analyzes LLDP information received from neighbors

    • CDP Aware: The CDP operation is restricted to decoding incoming CDP frames (the switch does not transmit CDP frames). CDP frames are only decoded if LLDP on the interface is enabled.

      Only CDP TLVs that can be mapped to a corresponding field in the LLDP neighbors' table are decoded. All other TLVs are discarded (unrecognized CDP TLVs and discarded CDP frames are not shown in the LLDP statistics.). CDP TLVs are mapped onto LLDP neighbors' table:

      • CDP TLV Device ID is mapped to the LLDP Chassis ID field
      • CDP TLV Address is mapped to the LLDP Management Address field. The CDP address TLV can contain multiple addresses, but only the first address is shown in the LLDP neighbors' table.
      • CDP TLV Port ID is mapped to the LLDP Port ID field
      • CDP TLV Version and Platform is mapped to the LLDP System Description field

        Both CDP and LLDP support system capabilities, but the CDP capabilities cover capabilities that are not part of the LLDP. These capabilities are shown as others in the LLDP neighbors' table.

      If all interfaces have CDP awareness disabled, the switch forwards CDP frames received from neighbor devices. If at least one interface has CDP awareness enabled, then all CDP frames are terminated by the switch.

      Note: When CDP awareness on an interface is disabled, the CDP information is not removed immediately but gets removed when the hold time is exceeded.
    • Port Desc: When checked, the port description is included in LLDP information transmitted
    • Sys Name: When checked, the system name is included in LLDP information transmitted
    • Sys Descr: When checked, the system description is included in LLDP information transmitted
    • Sys Capa: When checked, the system capability is included in LLDP information transmitted
    • Mgmt Addr: When checked, the management address is included in LLDP information transmitted