The present invention provides an apparatus and system for buffering data in
a communication network with an arranged priority which enables traffic shaping.
A cell buffer unit (600) is arranged with a plurality of queues (614)
configured to store PDUs on-chip and off-chip. There are associated queues both
on-chip and off-chip for each priority queue. A cell buffer controller (620)
forwards PDUs to a predetermined priority queue and manages the transfer of PDUs
off-chip when a priority queue on-chip is fully occupied. The controller (620)
also manages the transfer of PDUs from the off-chip queue when the on-chip priority
queue becomes less than fully occupied.
