CWDM/DWDM Solutions

Wavelength Division Multiplexing (WDM) technology multiplies fiber capacity by multiplexing optical light signals of different wavelengths onto a single optical fiber.

Due to the physical nature of light, the signals on WDM wavelengths are completely independent from each other and data streams with different line-rates and protocols can be transported on a single fiber or fiber pair.

Figure A: Multiple WAN Fibers San Extension

Traditional telecom signals (PDH, SDH/SONET), IP data (Ethernet, Gigabit Ethernet or 10G Ethernet) and storage data (8G/4G/2G/1G Fibre Channel) can therefore be transported over a single infrastructure without complex protocol conversion technologies.

WDM comes in two flavours: CWDM and DWDM. CWDM channel spacing is 20 nm and is typically used for un-amplified transmission up to 200 Km. DWDM uses cooled lasers and can also be amplified. The channel spacing of DWDM is typically 200GHz (ca. 0.8 nm). DWDM channels are usually used in the 1530-1560 nm band.

SAN Distance Extension Solution
In SAN distance extension, C/DWDM is used to reduce the number of required WAN fibers. The illustrations below shows a SAN Extension in a Brocade environment between a primary site and a secondary site.

Figure B: SAN extension over CWDM 1 fiber pair

In figure A) the implementation requires several WAN fibers to achieve the required capacity. In figure B) C/DWDM is used to optically multiplex several ISL signals onto a single fiber pair.

C/DWDM SFPs are plugged directly into the E-Ports/ISLs from the Fibre Channel switch to generate ISL signals of specific C/DWDM wavelength. The C/DWDM mulitplexer(Mux) combines these wavelength signals onto a fiber pair, the C/DWDM Demultiplexer (Demux) splits these wavelengths into several fibers on the receiver site. The number of required WAN fibers is reduced by the number of wavelength used.

For additional information about Zibiz SAN Distance Extension Solutions or for a customer tailored configuration please contact Zibiz Data Management today: 631-738-1100 or contact us about SAN Extension by filling out our contactform. Or go to our brochures section to read the SAN Distance Extension brochure.

Passive C/DWDM Solutions
To build a passive WDM system, two types of components are required:

Optical Multiplexer Units(OMUs) - which combine and split light signals of WDM wavelengths
WDM transceivers - which generate light signals of specific WDM wavelenghts

Passive Filters
A Mux/Demux unit terminates all wavelengths on the WDM system and is at the heart of point-to-point connections. The optical combining and splitting of wavelengths is a passive technology and a Mux/Demux requires neither electrical power nor software resulting in greatly increased reliability. See figure A below:

Figure A: Wavelength signal paths in 8 ch Mux/Demux unit

Figure B: Signal paths in 1 ch OADM with Wavelength Re-use

An Optical Add/Drop Multiplexer (OADM) terminates a limited subset of wavelengths in WDM systems. OADMs typically add/drop 1,2, or 4 wavelenghts and the remaining wavelengths are bypassed (expressed) through the fiber. It is possible to reuse the terminated wavelengths on the remaining span. See figure B here above. The ability to reuse wavelengths in OADMs enables network designers to build redundant WDM networks. Protection switching is usually taken care of in the client equipment.

For additional information about Zibiz Passive C/DWDM Solutions or for a customer tailored configuration please contact Zibiz Data Management today: 631-738-1100 or contact us about C/DWDM Passive Solutions by filling out our contactform. Or go to our brochures section to read the Passive C/DWDM Solutions brochure.

Active C/DWDM Solutions
For most SAN & Data Centre connections, the passive C/DWDM solutions offers best in class performance at excellent service delivery price points. However, sometimes active C/DWDM solutions are required, in the case of longer distances between sites or if a switch vendor restricts the use of alternative transceivers in their equipment. An Active C/DWDM solution is then in place.

For additional information about Zibiz Active C/DWDM Solutions or for a customer tailored configuration please contact Zibiz Data Management today: 631-738-1100 or contact us about Active C/DWDM Solutions by filling out our contactform. Or go to our brochures section to read the Active C/DWDM Solution brochure.

Brochures About C/DWDM solutions
The following brochures are designed to give a brief overview of the related technology and help the reader with network designs, technology choices and decision making.

View Green SAN Distance Extension solution brochure

View SAN Distance Extension solutions brochure

View Passive WDM solutions brochure

View Active WDM solutions brochure

For additional information about Zibiz C/DWDM Solutions or for a customer tailored configuration please contact Zibiz Data Management today: 631-738-1100 or contact us about C/DWDM Solutions by filling out our contactform.