How Dldp Works - HPE FlexFabric 5700 Series Configuration Manual

DLDP timer
DLDP authentication mode
You can use DLDP authentication to prevent network attacks and illegal detecting.
Table 9 DLDP authentication mode
Authentication
mode
Non-authentication
Plaintext
authentication
MD5
authentication

How DLDP works

Detecting one neighbor
When two devices are connected through an optical fiber or network cable, enable DLDP to detect
unidirectional links to the neighbor. The following illustrates the unidirectional link detection process
in two cases:
•
Unidirectional links occur before you enable DLDP.
Figure 7 Cross-connected fibers
As shown in
B are cross-connected. After you enable DLDP, the four ports are all up and in Unidirectional
state, and they send RecoverProbe packets. Take Port 1 as an example to illustrate the
unidirectional link detection process.
a. Port 1 receives the RecoverProbe packet from Port 4, and returns a RecoverEcho packet.
b. Port 4 cannot receive any RecoverEcho packet from Port 1, so Port 4 cannot become the
neighbor of Port 1.
c. Port 3 can receive the RecoverEcho packet from Port 1, but Port 3 is not the intended
destination, so Port 3 cannot become the neighbor of Port 1.
The same process occurs on the other three ports. The four ports are all in Unidirectional state.
•
Unidirectional links occur after you enable DLDP.
Description
RecoverProbe packets to detect whether a unidirectional link has been restored
to bidirectional.
Processing at the DLDP packet sending side
The sending side sets the Authentication field of DLDP
packets to 0.
The sending side sets the Authentication field to the
password configured in plain text.
The sending side encrypts the user configured password
using MD5 algorithm, assigns the digest to the
Authentication field.
Figure 7, before you enable DLDP, the optical fibers between Device A and Device
32
Processing at the
DLDP packet
receiving side
The receiving side
checks the
authentication
information of received
DLDP packets and
drops packets where the
authentication
information conflicts with
the local configuration.