A
network processor system includes a
network processor 1, which is provided with a number of interfaces 9, 11, 13, 15, 19, including one or more
Ethernet interfaces 9, 11 and a UART interface 19, which can be used to load a
software package into the
network processor 1. The
software package can thus be modified when required, or when the
software package previously stored in the network processor
system is corrupted. The
Ethernet data packets received on the
Ethernet interfaces 9, 11 are in a special format, which the network processor 1 can recognize, to distinguish them from conventional Ethernet packets. Thus, the network processor 1 does not have to be programmed to
handle the full range conventional Ethernet data packets. The network processor 1 is provided with a second external non-volatile data storage device 7 in the form of a
EEPROM memory 7. The
EEPROM memory 7 provides a writable extension of the internal ROM memory of the network processor. It can, for example, be used to store the parameters of other components of a network processor
system (e.g. a
flash memory 5) so that the network processor 1 can be used in conjunction with components of a wide range of types.