Refer to the exhibit. CE1 and CE2 use connectivity over the service provider cloud to reach CE3. In the event of a link failure in the service provider cloud, which BGP feature relies on IGP…

Question

Exhibit

Options

• ABGP graceful restart
• BBGP route dampening
• CBOP PIC core
• DBGP confederations

• A
  4% (2)
• B
  14% (7)
• C
  76% (39)
• D
  6% (3)

Explanation

BGP PIC (Prefix Independent Convergence) Core pre-computes and pre-installs backup paths into the forwarding table before any failure occurs. When a link failure happens in the SP cloud, PIC Core relies on IGP convergence to detect that failure and immediately triggers a local repair using the already-staged backup path - bypassing the need to wait for full BGP reconvergence, which is much slower.

Why the distractors are wrong:

• A. BGP Graceful Restart maintains forwarding state during a BGP speaker restart (e.g., control plane failure), not link failures - and it deliberately delays reconvergence, not speeds it up.
• B. BGP Route Dampening suppresses flapping routes to reduce instability; it has no role in installing backup paths quickly.
• D. BGP Confederations splits a large AS into sub-ASes to reduce IBGP full-mesh complexity - purely a scalability/design feature, unrelated to fast failover.

Memory tip: Think of PIC Core as "Pre-Installed Coverage" - the backup path is already loaded in the FIB before disaster strikes, so when IGP says "link is down," the switch to the backup is nearly instantaneous.

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