On this article, we talked about SNCP as you know. And SNCP has a brother and his name is MSP and used for protection and redundancy in network topologies ! 🙂 They are similar protocols but differences surely. MSP is examined in two categories which are 1+1 and N:1.
- In single ended mode the protection is accomplished by switching only the signal affected by the failure.
- In dual ended mode the protection is accomplished by switching both the affected and the unaffected signals, on both directions.
MS linear trail Protection (1+1 linear APS) :
- 1+1 linear APS (single ended/dual ended MSP): line protection for STM-N interfaces only.
- Switching criteria are : LOS, LOF, MS-AIS, Excessive BER (B2), Signal Degrade (B2), or card failure
- Note that each STM-1 electrical stream can be protected by an optical stream and vice versa.
- Switching signaling (in dual ended) is carried over the APS channel (K1 and K2 bytes), using the Kbyte protocol.
MSP N:1 :
- -Not operative on 1642EM R3.0 ; 1642EMC R1.2.
- -MS linear trail Protection (N:1 linear dual ended APS)
N:1 (N= 15 max) linear protection without extra traffic for STM-N interfaces only.One section is used as spare resource to protect one of the main sections when in failure.Switching criteria are: LOS, LOF, MS-AIS, Excessive BER (B2), Signal Degrade (B2) or card failure.
Note that each STM-1 electrical stream can be protected by an optical stream and vice versa.Only REVERTIVE mode is supported.The WTR is fixed to 5 minutes.In this mechanism the priority (High or Low) can be assigned to the main resource so that in case of double failure the high priority traffic is restored