H3C Technologies H3C S3100 Series Switches - Manual (Page 198)

1-9
Link Auto-recovery Mechanism
If the shutdown mode of a port is set to auto shutdown, the port is set to the DLDP down state when
DLDP detects the link connecting to the port is a unidirectional link. A port in DLDP down state does not
forward service packets or receive/send protocol packets except DLDPDUs.
A port in the DLDP down state recovers when the corresponding link recovers. A port in the DLDP down
state sends recover probe packets periodically. On receiving a correct recover echo packet (which
means that the unidirectional link is restored to a bidirectional link), it is brought up by DLDP. The
detailed process is as follows.
1) A port in the DLDP down state sends a recover probe packet every 2 seconds. Recover probe
packets carry only the local port information.
2) Upon receiving a recover probe packet, the peer end responds with a recover echo packet.
3) Upon receiving a recover echo packet, the local end checks to see if the neighbor information
carried in the recover echo packet is consistent with that of the local port. If yes, the link between
the local port and the neighbor is considered to be recovered to bidirectional, the port changes from
the disable state to the active state, and neighboring relationship is reestablished between the local
port and the neighbor.
Only ports in the DLDP down state can send and process recover probe packets and recover echo
packets. The auto-recovery mechanism does apply to ports that are shut down manually.
DLDP Configuration
Performing Basic DLDP Configuration
Follow these steps to perform basic DLDP configuration:
To do … Use the command … Remarks
Enter system view system-view —
Enable DLDP on all optical
ports of the switch
dldp enable
Enter Ethernet
port view interface interface-type
interface-number
Enable
DLDP
Enable DLDP
on the current
port (a
non-optical
port or an
optical port)
Enable DLDP dldp enable
Required.
By default, DLDP is
disabled.
Set the authentication mode and
password
dldp
authentication-mode
{ none | simple
simple-password | md5
md5-password }
Optional.
By default, the
authentication mode is
none.
Set the interval of sending DLDP packets dldp interval timer-value
Optional.
By default, the interval is 5
seconds.