Ethernet service OAM focuses on the maintenance of end-to-end Ethernet links, while Ethernet port OAM focuses on the maintenance of point-to-point Ethernet links between two directly connected devices.

Currently, 32-bit IP addresses are no longer sufficient, and MPLS labels are only 20 bits, so MPLS labels will not be sufficient as the network becomes larger.

Which of the following statements about extended ECC is wrong?

Both PDH and SDH have globally unified standards.

In WDM systems, when fewer than () wavelengths are used, it is ideal to use dielectric thin film filters (TFFs).