Dell Force10 C150 Configuration Manual page 584

Figure 26-1. Type, Length, Value (TLV) Segment
TLV Header
TLV Type
(1-127)
7 bits
TLVs are encapsulated in a frame called an LLDP Data Unit (LLDPDU)
transmitted from one LLDP-enabled device to its LLDP-enabled neighbors. LLDP is a one-way protocol.
LLDP-enabled devices (LLDP agents) can transmit and/or receive advertisements, but they cannot solicit
and do not respond to advertisements.
There are five types of TLVs. All types are mandatory in the construction of an LLDPDU except Optional
TLVs. The inclusion of individual Optional TLVs is user configurable.
Table 26-1. Type, Length, Value (TLV) Types
Type TLV
0 End of LLDPDU
1 Chassis ID
2 Port ID
3 Time to Live
— Optional
Figure 26-2. LLDPDU Frame
Preamble Start Frame
Delimiter
584 | Link Layer Discovery Protocol
TLV Length
Value
9 bits 0-511 octets
Chassis ID Sub-type Chassis ID
1- 255 octets
1 octet
Description
Marks the end of an LLDPDU
An administratively assigned name that identifies the LLDP agent
An administratively assigned name that identifies a port through which TLVs are sent
and received
A value that tells the receiving agent how long the information contained in the TLV
Value field is valid
Includes sub-types of TLVs that advertise specific configuration information. These
sub-types are Management TLVs, IEEE 802.1, IEEE 802.3, and TIA-1057
Organizationally Specific TLVs.
Destination MAC Ethernet Type
Source MAC
(01:80:C2:00:00:0E) (0x88CC)
TLV 1 TLV 2 TLV 3
Chassis ID Port ID Port Description
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LLDPDU
TLV 6
TLV 4 TLV 5
System Capabilities
System Name System Description
(Figure 26-2), which is
Padding FCS
TLV 7 TLV 127
Management Addr Organizationally Specific
TLV 0
End of LLDPDU
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