| 摘要 |
A telecommunications system having 1:n group facility protection is disclosed. Two cross-connects (2A, 2B) are provided, each organized in a distributed fashion, and which have a group of member ports (MA, MB) bidirectionally coupled to one another in corresponding fashion via a plurality of paths (4), such as of the DS-3 data frame type. Each of the cross-connects (2A, 2B) also include a bidirectional protection port (PA, PB), coupled to the protection port (PB, PA) of the other cross-connect (2B, 2A) by way of a protection path (P), also preferably of the DS-3 type; the protection port (PA, PB) for each cross-connect (2A, 2B) is assigned to the member port group (MA, MB), and is implemented to be managed by the same distributed interface processing unit (16) as the protected member port group (MA, MB). The cross-connects (2A, 2B) monitor (30) their member input ports (MA, MB) for received facility errors, such as signal failures (SF) or excessive failure rates, and request (34) a third-stage bridge from its mate cross-connect (2B) in the event of such error. Upon receipt of a good signal at the protection input port (PAI), the requesting cross-connect (2A) effects (38) a first stage switch (1SSW), so that the previously failing facility is received over the protection path (P). Communication of request and acknowledge signals over the protection path (P) is preferably by way of the C-bit and X-bit channels, for DS-3 paths. The switch preferably reverts (72) to the normal condition responsive to the facility becoming valid for a timeout period at the original member port (MA1I). <IMAGE> <IMAGE> <IMAGE> |
