Dell PowerConnect FCS624S Configuration Guide - Page 733

General operating principles 24 TABLE 122 Port ID subtypes ID subtype Description 0 1 2 3 4 5 6 7 8 - 255 Reserved Interface alias Port component MAC address Network address Interface name Agent circuit ID Locally assigned Reserved Dell PowerConnect devices use port ID subtype 3, the permanent MAC address associated with the port. Other third party devices may use a port ID subtype other than 3. The port ID appears similar to the following on the remote device, and in the CLI display output on the Dell PowerConnect device (show lldp local-info). Port ID (MAC address): 0012.f233.e2d3 The LLDPDU format is shown in "LLDPDU packet format" on page 688. The Port ID TLV format is shown below. FIGURE 118 Port ID TLV packet format TLV Type = 3 TLV Information String Length = 2 Time to Live (TTL) 7 bits 9 bits 2 octets TTL value The Time to Live (TTL) Value is the length of time the receiving device should maintain the information acquired by LLDP in its MIB. The TTL value is automatically computed based on the LLDP configuration settings. The TTL value will appear similar to the following on the remote device, and in the CLI display output on the Dell PowerConnect device (show lldp local-info). Time to live: 40 seconds If the TTL field has a value other than zero, the receiving LLDP agent is notified to completely replace all information associated with the LLDP agent/port with the information in the received LLDPDU. If the TTL field value is zero, the receiving LLDP agent is notified that all system information associated with the LLDP agent/port is to be deleted. This TLV may be used, for example, to signal that the sending port has initiated a port shutdown procedure. The LLDPDU format is shown in "LLDPDU packet format" on page 688. The TTL TLV format is shown below. PowerConnect B-Series FCX Configuration Guide 691 53-1002266-01