A multi-stage clock distribution scheme for use in a signaling server
organized into a plurality of uniquely addressable shelves. The signaling
server includes a system timing generator, one or more clock distribution
modules arranged in a nested hierarchical manner, and a plurality of bus
control modules, wherein each bus control module interfaces with at least
a portion of line cards disposed in a shelf. The system timing generator
provides a framed serial control signal, SFI, for controlling the
operation of the multi-stage clock distribution scheme. The SFI signal
encodes the IDs of the clock distribution modules and bus control modules
whereby a system clock generated by the system timing generator based on a
select reference input is successively fanned-out by the intermediate
clock distribution modules based on address and ID information encoded in
select fields of the SFI frames until the fanned-out system clocks are
received by the bus control modules. Thereafter, each bus control module
provides a copy of the system clock to the line cards controlled by it
based on the SFI signal.