3com 5500-ei pwr Instruccion De Instalación

 

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To enable the neighboring devices to be informed of the existence of a device or an LLDP operating 

mode change (from the disable mode to TxRx mode, or from the Rx mode to Tx mode) timely, a device 

can invoke the fast sending mechanism. In this case, the interval to send LLDPDUs changes to one 

second. After the device sends specific number of LLDPDUs, the interval restores to the normal. (A 

neighbor is discovered when a device receives an LLDPDU and no information about the sender is 

locally available.)  

An LLDP-enabled device operating in TxRx mode or Rx mode checks the TLVs carried in the LLDPDUs 

it receives and saves the valid neighboring information. An LLDPDU also carries a TTL (time to live) 

setting with it. The information about a neighboring device maintained locally ages out when the 

corresponding TTL expires.  

The TTL of the information about a neighboring device is determined by the following expression: 

TTL multiplier × LLDPDU sending interval 

You can set the TTL by configuring the TTL multiplier. Note that the TTL can be up to 65535 seconds. 

TTLs longer than it will be rounded off to 65535 seconds. 

TLVs encapsulated in LLDPDUs fall into these categories: basic TLV, organization defined TLV, and 

MED (media endpoint discovery) related TLV. Basic TLVs are the base of device management. 

Organization specific TLVs and MED related TLVs are used for enhanced device management. They 

are defined in standards or by organizations and are optional to LLDPDUs.  

 lists the basic LLDP TLV types that are currently in use. 

Table 1-1 Basic LLDP TLVs 

End of LLDPDU TLV 

Marks the end of an LLDPDU.  

Chassis ID TLV 

Carries the bridge MAC address of the 
sender  

Port ID TLV 

Carries the sending port. For devices 
that do not send MED TLVs, port ID TLVs 
carry sending port name. For devices 
that send MED TLVs, port ID TLVs carry 
the MAC addresses of the sending ports 
or bridge MAC addresses (if the MAC 
addresses of the sending ports are 
unavailable). 

Time To Live TLV 

Carries the TTL of device information 

Required for LLDP 

Port Description TLV 

Carries Ethernet port description 

System Name TLV 

Carries device name 

System Description TLV 

Carries system description 

System Capabilities TLV 

Carries information about system 
capabilities 

Optional to LLDP