| 摘要 |
A packet switched communications network comprises a controller (11) and a plurality of controlled units (12, 13, 14) arranged in a ring. Each of the controlled units comprises a switch (31) at its input, the switch including control means (44) responsive to control instructions contained in packets transmitted by the controller (11). The control means (44) is arranged to configure the switch (31) so that in a first configuration (1,1) the switch (31) passes control instructions and data into or out of the controlled unit (12, 13, 14) and in a second configuration (3,3) the switch (31) bypasses the unit (12, 13, 14) and passes the control instructions and data to a further controlled unit (12, 13, 14) connected to the controller (11) or back to the controller (11). |
