H3C S7500 Series Ethernet Switches Operation Manual

Operation Manual – DLDP
H3C S7500 Series Ethernet Switches Chapter 1
DLDP Configuration
1-6
Table 1-4 Processing procedure when no echo packet is received from the neighbor
No echo packet received from the
neighbor
Processing procedure
In normal mode, no echo packet is
received when the echo waiting timer
expires.
In enhanced mode, no echo packet is
received when the enhanced timer
expires
DLDP switches to the disable state,
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. DLDP sends RSY messages
and removes the corresponding
neighbor entries.
1.2.2 DLDP Status
A link can be in one of these DLDP states: initial, inactive, active, advertisement, probe,
disable, and delaydown.
Table 1-5 DLDP status
Status Description
Initial Initial status before DLDP is enabled.
Inactive DLDP is enabled but the corresponding link is down
Active
DLDP is enabled, and the link is up or an neighbor entry is
cleared
Advertisement
All neighbors communicate normally in both directions, or
DLDP remains in active state for more than five seconds and
enters this status. It is a stable state where no unidirectional link
is found
Probe
DHCP sends packets to check whether the link is a
unidirectional. It enables the probe sending timer and an echo
waiting timer for each target neighbor.
Disable
DLDP detects a unidirectional link, or finds (in enhanced mode)
that a neighbor disappears. In this case, DLDP sends and
receives only recover probe packets and recover echo packets.
DelayDown
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. After the DelayDown timer expires, the DLDP
neighbor information is removed.