256 BigIron RX Series Configuration Guide53-1001986-01General operating principles9FIGURE 17 LLDPDU packet formatEach LLDPDU consists of an untagged Ethernet header and a sequence of short, variable lengthinformation elements known as TLVs.TLVs have Type, Length, and Value fields, where:• Type identifies the kind of information being sent• Length indicates the length (in octets) of the information string• Value is the actual information being sent (for example, a binary bit map or an alpha-numericstring containing one or more fields).TLV supportThis section lists the LLDP TLV support.LLDP TLVsThere are two types of LLDP TLVs, as specified in the IEEE 802.3AB standard:• Basic Management TLVs consist of both optional general system information TLVs as well asmandatory TLVs.Mandatory TLVs cannot be manually configured. They are always the first three TLVs in theLLDPDU, and are part of the packet header.General system information TLVs are optional in LLDP implementations and are defined by theNetwork Administrator.Brocade devices support the following Basic Management TLVs:• Chassis ID (mandatory)• Port ID (mandatory)• Time to Live (mandatory)• Port description• System name• System description• System capabilities• Management address• End of LLDPDU• Organizationally-specific TLVs are optional in LLDP implementations and are defined andencoded by individual organizations or vendors. These TLVs include support for, but are notlimited to, the IEEE 802.1 and 802.3 standards and the TIA-1057 standard.Brocade devices support the following Organizationally-specific TLVs:Chassis IDTLVPort IDTLVTime toLive TLVOptionalTLVOptionalTLVEnd ofLLDPDU TLV...M M M MM = mandatory TLV (required for all LLDPDUs)
