HPE FlexNetwork HSR6800 series Configuration Manual page 41

Table 12 DLDP mode and neighbor entry aging
DLDP mode
Normal DLDP
mode
Enhanced
DLDP mode
Table 13 shows the relationship between DLDP modes and unidirectional link types.
Table 13 DLDP mode and unidirectional link types
Unidirectional
link type
Cross-connected
link
Connectionless
or broken link
Enhanced DLDP mode is designed for addressing black holes. It prevents situations where one end
of a link is up and the other is down.
If you configure forced speed and full duplex mode on a port, the situation shown in
occur (take the fiber link for example). Without DLDP enabled, the port on Router B is actually down
but its state cannot be detected by common data link protocols, so the port on Router A is still up.
However, in enhanced DLDP mode, the following occurs:
•
The port on Router B is in Inactive DLDP state because it is physically down.
•
The port on Router A tests the peer port on Router B after the Entry timer for the port on Router
B expires.
•
The port on Router A transits to the Disable state if it receives no Echo packet from the port on
Router B when the Echo timer expires.
Figure 8 A scenario for the enhanced DLDP mode
GE3/0/1
(up)
Router A
Ethernet
fiber port
DLDP authentication mode
You can use DLDP authentication to prevent network attacks and illegal detecting. The following
DLDP authentication modes are available:
•
Non-authentication:
Detecting a neighbor
after the
corresponding
neighbor entry ages
out
No
Yes
Whether it
Whether it
occurs on
occurs on
copper
fibers
twisted pairs
Yes No
Yes Yes
GE3/0/1
(down)
Tx end Rx end
Fiber link Unconnected or broken fiber
Removing the neighbor
entry immediately after
the Entry timer expires
Yes
No
In which DLDP mode unidirectional links
can be detected
Both normal and enhanced modes
Only enhanced mode. The port that can receive
signals is in Disable state, and the port that does
not receive signals is in Inactive state.
Router B
34
Triggering the
Enhanced timer after an
Entry timer expires
No
Yes
Figure 8 might