“…In recent years, both mathematicians and physicists have devoted remarkable effort to the study of numerical solutions of singularly perturbed delay differential equations with discontinuous data and large delay parameter. For instance, in [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , the authors suggested different numerical methods for solving singularly perturbed ordinary differential equations with discontinuous coefficients and large delay parameter using fitting techniques. Mukherjee and Natesan [24] developed the implicit upwind finite difference scheme on Shishkin-type meshes for a class of singularly perturbed parabolic convection-diffusion problems exhibiting strong interior layers.…”