The present invention provides a method, computer-readable medium and device for dynamically managing allocation of bandwidth in a packet network using a Dynamic Setting Scheme for Class Based Queuing. In addition, the invention provides methods for nucleobase characterisation, SNP characterisation and nucleic acid sequencing. And the first actuator means is configured to modulate the optical path length between first and second reflecting elements by a modulation amplitude to thereby sweep the optical resonator cavity through a band of optical resonance frequencies with a sweep frequency of 70 kHz or more. A second ring is adapted to be mounted on the head tube. The first mixer element has 3N pairs of differential inputs, wherein there are non-overlapping clock signals provided to the first mixer element which have a duty cycle equal to or less than 33\u2153 percent, and N is a positive integer.