What are the precautions for connecting optical interfaces on the mid-range-and-low-end routers?
1. If the optical interface is Down, you are recommended to test whether the sending and receiving of the optical power meet the requirement.
2. According to the loopback test through software and physical loopback test, we find that the optical attenuation test should be performed for single-mode modules.
3. If the optical interface cannot become Up after the preceding method is used, you are recommended to run the force-link command to enable the GE interface to work in forcible mode. By default, a GE interface works in negotiation mode. Interfaces on devices of other manufacturers may work in forcible mode by default. When one interface works in forcible mode while the remote interface works in negotiation mode, the interface in negotiation mode is Down and the interface in forcible mode is Up. Both interfaces become Up only when they work in the same mode.