Optical Add/Drop Multiplexers (OADMs) have been used for years to route specific, fixed wavelengths at a network location. Selected wavelengths are “nailed up” according to the initial network design.
Reconfigurable Optical Add/Drop Multiplexers (ROADMs) have been deployed in recent years to enable the flexible routing of wavelengths, using a variety of switching technologies. However, the flexibility that ROADMs provide is limited to the specific wavelengths allocated to the ROADM.
AFM can be used in concert with ROADM to provide additional, cost-effective flexibility.
For a brief on AFM’s use in providing directionless ROADM connectivity, please request our Application Brief on Combined AFM and ROADM. ROADM Client Management
AFM can be deployed on the client/wavelength side of a ROADM to provide an additional layer of wavelength reconfigurability. In this configuration, AFM can be used to manage and distribute wavelengths between multiple ROADM systems, or to switch “stand-by” wavelengths to a line on any ROADM system in response to an outage. These capabilities enable new wavelengths (beyond those fixed wavelengths initially allocated to a given ROADM) to be available for add/drop reconfiguration. It also enables multiple ROADMs to be connected to one another (including the ROADMs of different vendors) without consuming expensive ROADM ports.
ROADM Bypass – Reconfigurable Pass-Thru Traffic
In many long-haul and metro sites, the majority of the traffic passes through the location. Due to ROADM’s limited scale (in terms of fiber and wavelength count), network designers may pre-determine which lines run through the ROADM, and which bypass the ROADM and pass straight thru the facility. Only traffic on lines connected to the ROADM may be added/dropped at the location. By connecting pass-thru lines to AFM, this traffic can later be remotely connected to the ROADM, where individual wavelengths can be managed according to changing demand.
Wavelength Management
In certain instances, AFM may be deployed with traditional DWDM to select wavelengths to be added/dropped at the site, to add new wavelengths to a line, or to change the allocation of wavelengths between lines. In this implementation, AFM is connected to the wavelength/client side of the DWDM system.
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