3Com Switch 7754, Configuration Manual

Page: 221 / 940

DLDP Configuration 221
c
CAUTION:
■
This command only applies to the ports in DLDP down status.
■
If a port is DLDP down, it can return to the up state automatically. You do not
need to reset DLDP on the port.
Precautions During DLDP
Configuration
■
DLDP does not work on a port where you configure duplex and rate forcibly,
such as 10 GE port.
■
DLDP works only when the link is up.
■
To insure that DLDP neighbors can be established properly and unidirectional
links can be detected, you must make sure: DLDP is enabled on both ends, and
the interval of sending DLDP advertisement packets, authentication mode and
password are consistent on both ends.
■
You can adjust the interval of sending DLDP advertisement packets (which is 5
seconds by default and in the range of 1 seconds to 100 seconds) in different
network circumstances, so that DLDP can respond rapidly to link failure. The
interval must be shorter than one-third of the STP convergence time, which is
generally 30 seconds. If too long an interval is set, an STP loop may occur
before DLDP shut down unidirectional links. On the contrary, if too short an
interval is set, network traffic increases, and port bandwidth is reduced.
■
DLDP is also applicable to STP Discarding ports. Ports discarded by STP can set
up normal DLDP neighbors and detect unidirectional links.
■
DLDP does not process any LACP event, and treats each link in the aggregation
group as independent.
■
The mandatory duplex mode must be enabled on both ends of the DLDP link.
In this way, unidirectional links will be reported and the ports can be shut down
as required; if the auto-negotiation duplex mode is configured on both ends,
unidirectional links will not be reported and ports will not be shut down, while
only the state of DLDP neighbors changes.
■
If DLDP is enabled after unidirectional links appear, DLDP cannot detect
unidirectional links.
■
DLDP cannot be used together with similar protocols of other companies, that
is, you cannot enable DLDP on one end and enable one of the similar protocols
of other companies.
Table 151 Reset DLDP status
Operation Command Description
Reset the
status of
DLDP Enter system view system-view -
Reset the status of DLDP globally dldp reset Optional
Reset the
status of
DLDP on a
port Enter Ethernet port
view interface
interface-type
interface-number
-
Reset the status of
DLDP on 100 M
Ethernet ports dldp reset Optional
Reset the status of
DLDP on Gigabit
Ethernet ports dldp reset