Summary
The key components involved in this process are:
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PCC: The device managing the LSP delegation.
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PCE: The entity that computes and delegates LSPs.
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Label switched path (LSP): The network path being delegated and managed.
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Delegation fallback timer: A specific timer that governs the return of an LSP to its original PCE.
The PCC-centric redundancy model maintains high availability for Label Switched Paths (LSPs) in PCEP environments by managing the delegation of LSPs between primary and alternate Path Computation Elements (PCEs). The process includes automatic failover to an alternate PCE when the original becomes unreachable and graceful restoration to the primary PCE once it recovers, coordinated by a delegation fallback timer.
Workflow
These stages describe the PCC-Centric Redundancy Model.
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Initial LSP delegation: After an LSP is created, the PCC automatically delegates it to the specific PCE that computed the LSP.
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PCE disconnection handling: If the original PCE (to which the LSP was delegated) becomes disconnected or unreachable, the PCC automatically re-delegates the LSP to another available PCE.
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Original PCE reconnection and fallback: If the original PCE reconnects and becomes reachable again, a "delegation fallback timer" is initiated by the PCC. Once this timer expires, the LSP is re-delegated back to the original PCE, even if that PCE has a worse preference than the currently active PCE. This action ensures that LSPs eventually return to their primary, originating PCE.