Huawei Quidway S3900 Series Operation Manual page 205

Operation Manual - DLDP
Quidway S3900 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 normal mode, if no packet is received from the neighbor when
aging
the entry aging timer expires, DLDP sends an advertisement
packet with RSY tag, and deletes the neighbor entry
In enhanced mode, if no packet is received from the neighbor
when the entry aging timer expires, DLDP enables the enhanced
timer
The interval set for the entry aging timer is three times of that for
the advertisement timer
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
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
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.
Huawei Technologies Proprietary
Description
1-4
Chapter 1 DLDP Configuration