| 摘要 |
The present invention relates to a system and a method respectively for protection switching in a communications network such as e.g. a telecommunications network which comprises a number of nodes. Each node comprises a number of signal equipment units (11, ..., 1n) providing access to/from the node. At least one redundant equipment unit (1n+1) is provided and a protection switching arrangement (10) is arranged for protecting signals to/from the equipment units. The switching arrangement (10) comprises a number of first switching means (21, ..., 2n) which connect to the access units (11, ..., 1n) and in said first switching means signal input/output means (31, ..., 3n; 41, ..., 4n) are arranged which provide conversion between external traffic signals and internal traffic signals. At least a number of the first switching means (21, ..., 2n) are connected to at least one second switching means (7) which in turn connects to said at least one redundant equipment unit (1n+1). When protection switching is needed for a signal to/from an equipment unit (11, ..., 1n), protection switching is done on an internal signal in at least two steps via a first switching means and a second switching means to/from a redundant access unit (1n+1). |
