The debate still lingers on. When it comes to protection and re-routing on High speed links, what is the benefit of using Optical ASON versus Electrical ASON.
The Optical ASON relates to lambda switching ( Also called WSON-Wavelength Switched Optical Network). This necessitates the need of using at minimum Multi degree and directionless functionality. Using colorless functionality gives more degree of freedom and flexibility since in case of non-availability of a particular wavelength, ROADM has the functionality to change the color of wavelength also. When it comes to Electrical ASON, it is referred to as “ODU switching” at electrical layer of OTN switch. This necessitates the use of OTN switch along with ROADM. While Optical ASON gives one an advantage of lambda switching; the Eletcrial ASON gives advantage of control over more granular traffic at ODU level going as low as 1G traffic. In contrast, lambda switching can help to save on transponder resources because the same transponder can change direction or color thus there is no need to have multiple transponders for multiple restoration paths-a benefit not available on electrical ASON which would need multiple lambda paths to be created from Day one. Electrical ASON on the other hand gives much faster restoration times compared to Optical ASON. So what is the verdict ?
The rule of thumb is following: If traffic granularity is less and the lambda is not filled completely, Electrical ASON is much more optimized and cost efficient, on the other hand if lambda is filled with traffic ( multiple ODUs occupying complete lambda) that needs same SLA of restoration ( Meaning complete Lamda needs to be switched) then Opitcal ASON is much more optimized and cost efficient and ends up saving on the number of transponders.