The LoopStar SONET product family provides traditional Add/Drop Multiplexer (ADM) functionality to deliver TDM and data services. SONET has a long history as the service providers’ transport mechanism of choice due to its reliability, traffic grooming capabilities, and simplified remote management. With recent developments in Ethernet over SONET (EOS), SONET ADMs now have the capability to effectively groom Ethernet traffic onto the SONET backbone. With the rise in FTTX deployments for triple play, and the SONET ADM’s ability to effectively transport both TDM and Ethernet traffic, the demand for SONET add/drop rings will continue to increase | LoopStar SONET Access and Transport Solutions SONET Add Drop Multiplexer Rings Overview The LoopStar SONET product family provides traditional Add Drop Multiplexer ADM functionality to deliver TDM and data services. SONET has a long history as the service providers transport mechanism of choice due to its reliability traffic grooming capabilities and simplified remote management. With recent developments in Ethernet over SONET EOS SONET ADMs now have the capability to effectively groom Ethernet traffic onto the SONET backbone. With the rise in FTTX deployments for triple play and the SONET ADM s ability to effectively transport both TDM and Ethernet traffic the demand for SONET add drop rings will continue to increase. Reliability SONET was designed to provide protection switching in the event of facility or equipment failures. There are two basic protection switch mechanisms for ring topologies Unidirectional Path Switched Rings UPSR and Bidirectional Line Switched Rings BLSR . All LoopStar SONET products support UPSR with the LoopStar 1600 supporting BLSR. APPLICATION NOTE Unidirectional Path Switched Rings UPSR UPSR makes switching decisions based on the signal quality of a single STS or VT With UPSR rings two counter-rotating rings are used one for the working traffic and one for the protection traffic. Since UPSR is implemented at the path level only nodes that terminate the path level are the only ones capable of performing the protection switch. Therefore the only nodes that can perform a protection switch are those that are terminating the STS or VT. When a UPSR ADM determines that a given path signal requires a protection switch it wraps the ring by selecting the protection path as the new active path. UPSR is typically used in access or smaller metro networks where a hub node aggregates the traffic. All LoopStar SONET products support UPSR protection switching. Fiber break causes adjacent nodes to wrap the ring to avoid the outage New Traffic path is out
