H3C Technologies H3C S5560 Series Switches - Manual (Page 28)

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IMPORTANT:
Copper ports do not support this feature.
As shown in Figure 1 , a fiber port typically uses separate fibers for transmitting and receiving packets.
The physical state of the fiber port is up only when both transmit and receive fibers are physically
connected. If one of the fibers is disconnected, the fiber port does not work.
To enable a fiber port to forward traffic over a single link, you can use the port up-mode command. This
command brings up a fiber port by force, even when no fiber links or optical modules are present. If one
fiber link is present and up, the fiber port can forward packets over the link unidirectionally.
Figure 1 Forcibly bring up a fiber port
Configuration restrictions and guidelines
When you forcibly bring up a fiber port, follow these guidelines:
• The port up-mode command is mutually exclusive with either of the shutdown and commands.
• A GE fiber port cannot correctly forward traffic if you configure the port up-mode command on the
port and install an electro-optical module, 100/1000-Mbps transceiver module, or 100-Mbps
transceiver module into the port. To solve the problem, use the undo port up-mode command on the
fiber port.
Configuration procedure
To forcibly bring up a fiber port:
Step Command Remarks
1. Enter system view. system-view N/A
Correct fiber
connection
When Ethernet interfaces
cannot be or are not
forcibly brought up
When Ethernet interfaces
are forcibly brought up
Fiber port Tx end Rx end The fiber is disconnected. Fiber link
GE1/0/1
GE1/0/1
Device A
Device B
GE1/0/1
GE1/0/1
Device A
Device B
GE1/0/1
GE1/0/1
Device A
Device B
The interface is down. Packets