We present an overview of Cluster's ability to determine the orientation, motion and thickness of boundary layers, and try to identify where and when a particular method is more suitable than another. With Cluster, three different principles can be used for discontinuity analysis; four-spacecraft timing methods, four-spacecraft gradient methods and single-spacecraft residue methods based on conservation laws. Timing methods make use of (and require) data from all four Cluster satellites. Boundary layer orientation, motion and thickness are determined from time differences between the crossings by the four spacecraft and the crossing duration. Variations of the timing methods can be used to take into account non-uniform thickness or non-constant motion of boundaries. Cluster's ability to determine gradients can also be used for discontinuity analysis. The orientation of a discontinuity can in some cases be obtained by examining the gradient of the field or plasma data directly. Alternatively, the gradient operator can be used to determine the electric current via Amperes law, or the time variation of the magnetic field via Faraday's law of induction. Variance analysis of these quantities thereafter give the orientation and integration across the discontinuity can be used to determine the velocity and thickness of the layer. Discontinuity analysis methods based on conservation laws and residue analysis may utilize data from one or more of the Cluster satellites, and can be combined with multispacecraft methods to improve these or for consistency checks. Constraints, for example by requiring the magnetic field to be tangential to the discontinuity or by requiring zero plasma flow respectively Alfvénic plasma flow across the discontinuity, can be used to improve the stability of the results.