Operation Manual – DLDP
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 DLDP Configuration
1-3
connected correctly and if packets can be exchanged between the two devices. Note
that DLDP is not implemented through auto-negotiation.
1.1.2 DLDP Fundamentals
I. DLDP link states
A device is in one of these DLDP link states: Initial, Inactive, Active, Advertisement,
Probe, Disable, and DelayDown, as described in
Table 1-1
DLDP link states
State
Description
Initial
This state indicates that DLDP is not enabled.
Inactive
This state indicates that DLDP is enabled but the link is down.
Active
This state indicates that:
z
DLDP is enabled and the link is up.
z
The neighbor entries are cleared.
Advertisement
This state indicates that a device can communicate normally
with all its neighbors in both directions or DLDP remains in
active state for more than five seconds. It is the normal state
where no unidirectional link is detected.
Probe
A device enters this state if it receives a packet from an
unknown neighbor. In this state, DLDP sends packets to check
whether the link is a unidirectional link. After a device enters
this state, the probe sending timer is triggered, and an echo
waiting timer is triggered for each neighbor to be detected.
Disable
A device enters this state when:
z
A unidirectional link is detected.
z
The contact with a neighbor in enhanced mode gets lost.
z
In this state, no DLDP packet is sent or accepted.
DelayDown
A device in the Active, Advertisement, or Probe DLDP link state
transits to this state rather than remove the corresponding
neighbor entry and transits to the Inactive state when it detects
a port-down event. When a device transits to this state, the
DelayDown timer is triggered.
