Zte ZXR10 2900E series Configuration Manual page 189

period of the neighbor. If the device does not receives a Hello message when the time-out
period expires, it is considered that the a fault occurs to the neighbor and the neighbor is
aged. If the last neighbor is deleted due to aging, it is considered that the link is not in
normal operating state. It is necessary to handle the problem according to working mode.
There are two UDLD working modes: normal mode and aggressive mode.
l
In normal mode, only when the device receives a protocol message confirming that
the link is connected incorrectly will the port be shut down. If the device does not
receive the related message or cannot confirm that the link is working properly in one
direction, the device does not operate the port.
l
In aggressive mode, if the device cannot confirm that the link is working properly in
both directions (such as the link is connected incorrectly, the link is working properly
only in one direction or the link is a self-loop), the port is shut down. It is necessary to
use the reset or recovery command to recover the communication ability of the port.
UDLD shuts down a port in the following situations.
l In both modes, when an Echo message is sent, the device detects that the neighbor
of the peer port is not the device itself during the final neighbor detection.
l
In aggressive mode, the status becomes PROBE because the last neighbor is aged,
and multiple Probe messages are sent continuously without any response.
l
In aggressive mode, the port receives the UDLD message sent by itself and there is
a self-loop.
To prevent a neighbor from being aged by mistake, a local device sends Flush messages
on its own initiative to the port on which the UDLD function is enabled in the following
situations.
l
The port is down administratively.
l
UDLD is down on the port.
l The device is restarted.
Configuring UDLD
The UDLD configuration includes the following commands:
Command
zte(cfg)#
zte(cfg)#
zte(cfg)#
zte(cfg)#
zte(cfg)#
SJ-20130731155059-002|2013-11-27 (R1.0)
udld port <portlist>{enable|disable}
udld port <portlist> mode {aggressive | normal}
udld port <portlist> message timer <7-90>
udld port <portlist> recovery {enable | disable}
udld port <portlist> recovery timer <10-600>
Chapter 5 Service Configuration
5-141
ZTE Proprietary and Confidential
Function
Enables or disables UDLD on a
port.
Sets the mode of a port in UDLD.
Sets the interval of sending
messages after UDLD enters the
BiDirectional status and the port is
steady.
Enables or disables the UDLD
recovery function.
Sets the recovery interval.