H3C S3600 Series Operation Manual page 5

Operation Manual – DLDP
H3C S3600 Series Ethernet Switches-Release 1510
Timer
Entry
timer
Enhanced
timer
Delaydown
timer
III. DLDP operating mode
DLDP can operate in two modes: normal and enhanced.
When a new neighbor joins, a neighbor entry is created and the
corresponding entry aging timer is enabled
When an advertisement packet is received from a neighbor, the
neighbor entry is updated and the corresponding entry aging timer
is updated
In the normal mode, if no packet is received from the neighbor
aging
when the entry aging timer expires, DLDP sends an advertisement
packet with an RSY tag, and deletes the neighbor entry.
In the enhanced mode, if no packet is received from the neighbor
when the entry aging timer expires, DLDP enables the enhanced
timer
The entry aging timer length is three times the advertisement timer
length.
In the 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 enhanced timer length is 10 seconds
The enhanced timer then sends one probe packet every second
and eight packets successively to the neighbor.
If no echo packet is received from the neighbor when the
enhanced timer expires, the state of the local end is set to
unidirectional communication state and the state machine turns
into the disable state. 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 prompts
you to disable the port manually. Meanwhile, 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
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.
Description
1-4
Chapter 1 DLDP Configuration