H3C Technologies H3C WX3000 Series Unified Switches - Manual (Page 157)

20-4
Timer Description
Delaydown timer
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 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 20-3 DLDP operating mode and neighbor entry aging
DLDP operating
mode
Whether DLDP
probes neighbor
during neighbor
entry aging
Whether entry aging
timer is enabled during
neighbor entry aging
Whether enhanced timer is
enabled when entry aging timer
expire
Normal mode No
Yes (the neighbor entry
ages after the entry aging
timer expires)
No
Enhanced mode Yes
Yes (the enhanced timer is
enabled after the entry
aging timer expires)
Yes (When the enhanced timer
expires, the local end is set to
single pass 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.
Table 20-4 Types of packets sent by DLDP
DLDP status Packet types
Active Advertisement packets, including those with or without RSY tags
Advertisement Advertisement packets
Probe Probe packets
2) DLDP analyzes and processes received packets as follows:
z
In authentication mode, DLDP authenticates the packets, and discards those do not pass the
authentication.
z
DLDP processes the received DLDP packets.