DELL 8132 ユーザーズマニュアル

LLDP Commands

The IEEE 802.1AB standard defines the Link Layer Discovery Protocol 

(LLDP). This protocol allows stations residing on an 802 LAN to advertise 

major capabilities, physical descriptions, and management information to 

physically adjacent devices, allowing a network management system (NMS) 

to access and display this information.
The standard is designed to be extensible, providing for the optional 

exchange of organizational specific information and data related to other 

IEEE standards. The base implementation supports only the required basic 

management set of type length values (TLVs). 
LLDP is a one-way protocol; there are no request/response sequences. 

Information is advertised by stations implementing the transmit function. 

The information is received and processed by stations implementing the 

receive function. Devices are not required to implement both transmit and 

receive functions and each function can be enabled or disabled separately by 

the network manager. PowerConnect supports both the transmit and receive 

functions in order to support device discovery.
The LLDP component transmit and receive functions can be 

enabled/disabled separately per physical port. By default, both transmit and 

receive functions are disabled on all ports. The application starts each 

transmit and receive state machine appropriately based on the configured 

status and operational state of the port.
The transmit function is configurable with respect to packet construction and 

timing parameters. The required Chassis ID, Port ID, and Time to Live 

(TTL) TLVs are always included in the Link Layer Discovery Protocol Data 

Unit (LLDPDU). However, inclusion of the optional TLVs in the 

management set is configurable by the administrator. By default, they are not 

included. The transmit function extracts the local system information and 

builds the LLDPDU based on the specified configuration for the port. In 

addition, the administrator has control over timing parameters affecting the 

TTL of LLDPDUs and the interval in which they are transmitted.

2CSPC4.X8100-SWUM102.book  Page 567  Friday, March 15, 2013  8:56 AM