> # Information About DWDM

> Dense Wavelength-Division Multiplexing (DWDM) multiplexes multiple optical carrier signals on a single optical fiber. DWDM uses different wavelengths to carry various signals.

> To establish a DWDM link, both ends of an Inter Switch Link (ISL) need to be connected with DWDM SFPs (small form-factor pluggable) at each end of the link. To identify a DWDM link, DCNM-SAN discovers the connector type on the Fiber Channel (FC) ports. If the ISL link is associated with the FC ports at each end, then the FC port uses DWDM SFP to connect the links.

> Cisco DCNM for SAN discovers FC ports with DWDM SFPs and the ISLs associated with the FC ports. The DCNM-SAN Client displays ISL with DWDM attribute on the topology map.

> Note The Fabric Shortest Path First (FSPF) database only displays an ISL link, which is connected with DWDM SFPs at both ends.

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