Networking Diagram
The networking diagram of a single two-fiber unidirectional MSP ring is simple. When you construct the network, follow a certain order to create and name these NEs and ensure that the traffic flows in a proper direction. This helps when you plan the traffic direction planning and service configuration in future.
As shown in Figure 1, the PQ1 boards are used on NE1 and NE3 as tributary boards to add and drop services, and the SL16 boards are used as line boards to transmit SDH services.
Figure 1 Networking diagram of the two-fiber unidirectional MSP ring
NOTE:
This topic considers the OptiX OSN 3500 as an example to describe the board layout. In the case of other products, the configuration method is the same, except for the slots. For the slot information, see the Hardware Description of the relevant product.
Signal Flow and Timeslot Allocation
To configure the two-fiber unidirectional MSP service, you can configure the service added to the ring network on the source NE, passing through the intermediate nodes, and dropped from the sink NE if the MSP protection Subnet is already created.
As shown in Figure 1, the signal flow and timeslot allocation are as follows:
Traffic direction from NE1 to NE3: NE1→NE2→NE3
Services are added to the ring on the source NE (NE1), pass through NE2, and finally are dropped from the sink NE (NE3). The capacity of the services is 5xE1.
Traffic direction from NE3 to NE1: NE3→NE4→NE1
Services are added to the ring on the source NE (NE3), pass through NE4, and finally are dropped from the sink NE (NE1). The capacity of the services is 5xE1.
VC-12s 1-5 of VC-4-1 carry the five E1 services for transmission.
When the transmission path between NE1 and NE2 becomes faulty, the signal flow and timeslot allocation are as follows:
Traffic direction from NE1 to NE3: NE1→NE4→NE3→NE2→NE3
Services are added to the ring on the source NE (NE1) and switched from the original working path to the protection path. Then, the services pass through NE4 and NE3. After that, the services are switched from the protection path to the working path on NE2. Finally, the services are dropped from NE3.
The services from NE3 to NE1 are not affected, and the traffic direction is NE3→NE4→NE1.
The difference between the two-fiber unidirectional MSP service and the two-fiber bidirectional MSP service is as follows:
The two-fiber unidirectional MSP service uses the diverse routes, whereas the two-fiber bidirectional MSP service uses the uniform route.
In the case of the two-fiber unidirectional MSP service, different optical fibers are used for the working timeslot and protection timeslot. That is, one optical fiber is used for carrying the working service, and the other optical fiber is used for protection. In the case of the two-fiber bidirectional MSP service, the same optical fiber is used for the working timeslot and protection timeslot. That is, a certain capacity of the optical fiber is used for carrying the working service, and a certain capacity of the optical fiber is used for protection.
Figure 1 Signal flow and timeslot allocation of the two-fiber unidirectional MSP service
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