Dell PowerConnect B-RX BigIron RX Series Configuration Guide v02.7.03 - Page 330

9 General operating principles There are several ways in which a port may be identified, as shown in Table 60. A port ID subtype, included in the TLV, indicates how the port is being referenced in the Port ID field. TABLE 60 ID Subtype Port ID subtypes 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 Brocade 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 Brocade device (show lldp local-info). Port ID (MAC address): 0012.f233.e2d3 The LLDPDU format is shown in "LLDPDU packet format" on page 256. The Port ID TLV format is shown below. FIGURE 18 Port ID TLV packet format TLV Type = 2 TLV Information String Length 7 bits 9 bits TLV Header Port ID Subtype Port ID 1 octet 1 < n < 255 octets TLV Information String TTL value The Time to Live (TTL) Value is the length of time the receiving device should maintain the information acquired through 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 Brocade 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 or port with the information in the received LLDPDU. 258 BigIron RX Series Configuration Guide 53-1001986-01