The outgoing LLDPDU contains all the preceding TLVs if applicable. For the incoming LLDPDU, the
LLDPDU is discarded if any of the following TLVs are missing. All other TLVs are not validated and ignored.
• Chassis ID TLV
• Port ID TLV
• Time to live TLV
• LLDP-MED Capabilities TLV
• LLDP-MED Network Policy TLV (for application type=Voice only)
• End of LLDPDU TLV
The Cisco IP Phone sends out the shutdown LLDPDU if applicable. The LLDPDU frame contains the following
TLVs:
• Chassis ID TLV
• Port ID TLV
• Time to live TLV
• End of LLDPDU TLV
There are some restrictions in the implementation of LLDP-MED on the Cisco IP Phones:
• Storage and retrieval of neighbor information are not supported.
• SNMP and corresponding MIBs are not supported.
• Recording and retrieval of statistical counters are not supported.
• Full validation of all TLVs does not take place; TLVs that do not apply to the phones are ignored.
• Protocol state machines as stated in the standards are used only for reference.
Chassis ID TLV
For the outgoing LLDPDU, the TLV supports subtype=5 (Network Address). When the IP address is known,
the value of the Chassis ID is an octet of the INAN address family number followed by the octet string for
the IPv4 address used for voice communication. If the IP address is unknown, the value for the Chassis ID is
0.0.0.0
. The only INAN address family supported is IPv4. Currently, the IPv6 address for the Chassis ID is
not supported.
For the incoming LLDPDU, the Chassis ID is treated as an opaque value to form the MSAP identifier. The
value is not validated against its subtype.
The Chassis ID TLV is mandatory as the first TLV. Only one Chassis ID TLV is allowed for the outgoing
and incoming LLDPDUs.
Port ID TLV
For the outgoing LLDPDU, the TLV supports subtype=3 (MAC address). The 6 octet MAC address for the
Ethernet port is used for the value of Port ID.
For the incoming LLDPDU, the Port ID TLV is treated as an opaque value to form the MSAP identifier. The
value is not validated against its subtype.
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Chassis ID TLV