H3C Technologies H3C S3100 Series Switches - Manual (Page 197)

1-8
Table 1-6 The procedure to process a received DLDP packet
Packet type Processing procedure
If the corresponding neighbor entry does not exist on the
local device, DLDP creates the neighbor entry, triggers
the entry aging timer, and switches to the probe state.
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packet Extracts neighbor
information
If the corresponding neighbor entry already exists on the
local device, DLDP resets the aging timer of the entry.
Flush packet Removes the neighbor entry from the local device
Creates the neighbor entry if it does not exist on the local
device.
Probe packet
Sends echo packets
containing both
neighbor and its own
information to the
peer
Resets the aging timer of the entry if the neighbor entry
already exists on the local device.
No Drops the echo packet
No Drops the echo packet
Sets the flag bit of the neighbor
to bidirectional link
Echo packet
Checks to
see if the
local device
is in the
probe state
Yes
Checks to
see if the
neighbor
information
contained in
the packet is
the same as
that on the
local device
Yes
If all neighbors are in the
bidirectional link state, DLDP
switches from the probe state to
the advertisement state, and
sets the echo waiting timer to 0.
3) If no echo packet is received from the neighbor, DLDP performs the following processing:
Table 1-7 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.
DLDP Neighbor State
A DLDP neighbor can be in one of these two states: two way and unknown. You can check the state of
a DLDP neighbor by using the display dldp command.
Table 1-8 Description on the two DLDP neighbor states
DLDP neighbor state Description
two way The link to the neighbor operates properly.
unknown The device is detecting the neighbor and the neighbor state is unknown.