1-7
Table 1-5
DLDP state and DLDP packet type
DLDP state
Type of the DLDP packets sent
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packets,
with the RSY flag set or not set.
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packets
Probe Probe
packets
2) A DLDP packet received is processed as follows:
z
In authentication mode, the DLDP packet is authenticated and is then dropped if it fails the
authentication.
z
The packet is further processed, as described in
Table 1-6
.
You can prevent network attacks and illegal detect through DLDP authentication. Three DLDP
authentication modes exist: non-authentication, plain text authentication, MD5 authentication.
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:
