Communication networks can be divided into local area networks, wide area networks, and metropolitan area networks between local area networks and wide area networks according to the geographical scope they cover. The characteristics of wide area networks are low latency, high data rate, and reliable transmission.

The current sparse wavelength division multiplexing system generally operates in the band from
1271nm to 1611nm. Which of the following is the channel spacing?

Optical monitoring channel is used for monitoring of WDM optical transmission systems. In the UU-T recommendation, it is preferable to use a 1510 nm wavelength of the a ") rate.

Which of the following IP addresses is a Class C IP address?

PRBS can be used to test that the SDH service is healthy and that the protection reversal function is working.