Timer

 

Description

 

 

 

In enhanced mode, if no packet is received from the neighbor

 

 

 

when the entry aging timer expires, DLDP enables the enhanced

 

 

 

timer for the neighbor. The timeout time for the enhanced timer is

 

 

 

10 seconds.

 

 

 

The enhanced timer then sends one probe packets every one

 

Enhanced timer

 

second and totally eight packets continuously to the neighbor.

 

 

If no echo packet is received from the neighbor when the

 

 

 

Enhanced timer expires, the local end is set to unidirectional

 

 

 

communication status and the state machine turns into disable

 

 

 

status. DLDP outputs log and tracking information, and sends

 

 

 

flush packets. Depending on the user-defined DLDP down mode,

 

 

 

DLDP disables the local port automatically or prompt the user to

 

 

 

disable the port manually. DLDP deletes the neighbor entry.

 

 

 

 

 

 

 

When a device in the active, advertisement, or probe DLDP state

 

 

 

receives a port down message, it does not removes the

 

 

 

corresponding neighbor immediately, neither does it changes to

 

 

 

the inactive state. Instead, it changes to the delaydown state first.

 

 

 

When a device changes to the delaydown state, the related DLDP

 

 

 

neighbor information remains, and the Delaydown timer is

 

Delaydown timer

 

triggered. The Delaydown timer is configurable and ranges from 1

 

 

to 5 seconds.

 

 

 

 

 

 

A device in the delaydown state only responds to port up

 

 

 

messages.

 

 

 

A device in the delaydown state resumes its original DLDP state if

 

 

 

it receives a port up message before the delaydown timer expires.

 

 

 

Otherwise, it removes the DLDP neighbor information and

 

 

 

changes to the inactive state.

 

 

 

 

DLDP operating mode

DLDP can operate in two modes: normal and enhanced.

Table 1-3DLDP operating mode and neighbor entry aging

 

 

Whether DLDP

Whether entry aging

Whether enhanced

 

DLDP operating

probes neighbor

timer is enabled

timer is enabled

 

mode

during neighbor

during neighbor

when entry aging

 

 

entry aging

entry aging

timer expire

 

 

 

Yes (the neighbor

 

 

Normal mode

No

entry ages after the

No

 

entry aging timer

 

 

 

 

 

 

 

expires)

 

 

 

 

 

 

 

 

 

 

Yes (When the

 

 

 

Yes (the enhanced

enhanced timer

 

Enhanced mode

Yes

timer is enabled after

expires, the local end

 

the entry aging timer

is set to single pass

 

 

 

 

 

 

expires)

status, and the

 

 

 

 

neighbor entry ages)

 

 

 

 

 

DLDP implementation

1)If the DLDP-enabled link is up, DLDP sends DLDP packets to the peer device, and analyses and processes DLDP packets received from the peer device. DLDP in different status sends different packets.

1-4

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3Com WX3000 Dldp operating mode, Dldp implementation, Enhanced timer then sends one probe packets every one