Protection-Switching Related Blog Posts

Basic Protection-Switching Terms

• Head-End (Source Node)
• Hold-Off Timer
• Protection-Group
• Protection-Transport entity
• Selector Switch
• Tail-End (Sink Node)
• Working-Transport entity

Protection Switching (Linear)

• What is Linear Protection-Switching?
• 1+1 Protection-Switching Architecture
• 1:N Protection-Switching Architecture

1+1 Protection-Switching Architecture

• Permanent Bridge

1:N Protection-Switching Architecture

• Broadcast Bridge
• Extra-Traffic Signal
• NULL Traffic Signal

Unidirectional Protection-Switching

• What is Unidirectional Protection-Switching?

Bidirectional Protection-Switching

• What is Bidirectional Protection-Switching?

Reverting Protection-Switching

• Wait-to-Restore
• The WTR (Wait-to-Restore) Command
• Advantages and Disadvantages of Using a Revertive Protection-Switching system

Non-Reverting Protection-Switching

• The DNR (Do-Not-Revert) Command

Types of Monitoring (for Protection-Switching)

SNC/I – Sub-Network Circuit/Inherent Monitoring

• What is SNC/I Monitoring – at the OTUk Layer?
• When will the Tail-End circuitry declare SF for SNC/I Monitoring – at the OTUk Layer?
• When will the Tail-End circuitry declare SD for SNC/I Monitoring – at the OTUk Layer?
• What is SNC/I Monitoring – at the ODUk Layer?
• When will the Tail-End circuitry declare SF for SNC/I Monitoring – at the ODUk Layer?
• When will the Tail-End circuitry declare SD for SNC/I Monitoring – at the ODUk Layer?

SNC/S – Sub-Network Circuit/Sublayer Monitoring

• What is SNC/S Monitoring?
• When will the Tail-End circuitry declare SF for SNC/S Monitoring?
• When will the Tail-End circuitry declare SD for SNC/S Monitoring?

SNC/Ne – Sub-Network Circuit/Non-Intrusive Monitoring – End-to-End

• What is SNC/Ne Monitoring?
• What Atomic Function do we use for SNC/Ne Monitoring?
• How is SNC/Ne Monitoring different from that of SNC/Ns Monitoring?  
• When will the Tail-End circuitry declare SF for SNC/Ne Monitoring?
• When will the Tail-End circuitry declare SD for SNC/Ne Monitoring

SNC/Ns – Sub-Network Circuit/Non-Intrusive Monitoring – Sublayer

• What is SNC/Ns Monitoring?
• What Atomic Function doe we use for SNC/Ns Monitoring?  
• How is SNC/Ns Monitoring different from that of SNC/Ne Monitoring?  
• When will the Tail-End circuitry declare SF for SNC/Ns Monitoring?
• When will the Tail-End circuitry declare SD for SNC/Ns Monitoring?

The APS/PCC Protection-Switching Protocol for Linear Protection Switching

• The APS/PCC field format for Linear Protection-Switching
• APS Command Priorities for Linear Protection-Switching
• The LoP (Lock-Out of Protection) Command
• The SF-P (Signal Fail in the Protection Transport Entity) Command
• The SF-W (Signal Fail in the Working Transport Entity) Command
• The SD-W (Signal Degrade in the Working Transport Entity) Command
• The SD-P (Signal Degrade in the Protection Transport Entity) Command

Protection Switching (ODUk Shared Ring)

• What is Shared-Ring Protection-Switching?

2-Fibre/2-Lambda Shared-Ring Protection-Switching Systems

4-Fibre/4-Lambda Shared-Ring Protection-Switching Systems

Span-Switching

• Span-Switching Example

Ring-Switching

• Ring-Switching Example