Protocols such as TCP and congestion control mechanisms like TFRC suffer in a hybrid wired-cum-wireless scenario where losses can occur for reasons other than congestion, viz. due to biterrors in the wireless link. The existing solutions to address the problem either misclassify the losses, violate end-to-end semantics, do not co-exist with IPSec or are TCP-specific. We have previously proposed an innovative mechanism, Secure Performance Enhancing Proxy (SPEP) which preserves end-to-end semantics, ensures end-to-end security and enhances performance. In this paper we show that the decoupling of loss differentiation from loss recovery mechanism enables SPEP to serve as a generic loss differentiation mechanism at the network layer. We show by means of test bed experiments that SPEP work in conjunction with any transport layer and protocols such as UDP with TFRC.