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CHAPTER
8-1
Cisco Active Network Abstraction 3.6.6 MPLS User Guide
OL-19192-01
8
Impact Analysis in MPLS Networks
The following topics provide an overview of the service impact analysis solution and supported
scenarios, which are used in VPN networks that are based on MPLS, including Layer 3 and Layer 2
VPNs. In addition, theybriefly describes proactive and automatic impact analysis.
• Service Impact Analysis Overview, page 8-1—Describes the service impact analysis solution.
• Service Impact Analysis For MPLS-Based VPN Services, page 8-2—Describes the impact analysis
process for Layer 3 VPN and pseudowire (Layer 2 VPN) scenarios.
• Supported Fault Scenarios, page 8-3—Describes the scenarios supported by the service impact
analysis solution.
Service Impact Analysis Overview
Cisco ANA analyzes network faults to identify the NEs involved in the VPN services (such as interfaces
on the PE) that are affected, or potentially affected, by the fault. After a fault occurs, Cisco ANA
automatically generates the list of potential and actual service resources affected by a fault and embeds
this information in the ticket along with all the correlated faults. (You can configure this behavior.)
Note Automatic impact analysis is not performed for every service alarm. It is performed for a small group of
selected alarms, for example, BGP Neighbor Loss, Broken LSP, Link Down, Layer 2 Tunnel Down, and
so on.
During Cisco ANA impact analysis, affected parties can be marked with one of the following severities:
• Potentially Affected—The service might be affected but its real state is unknown.
• Real Affected—The service is affected.
• Recovered—The service has recovered. This state applies only to entries that were previously
marked as potentially affected. It indicates only that there is an alternate route to the service,
regardless of the service quality level)
The initial impact report may mark the services as either Potentially Affected or Real Affected. As time
progresses and more network information is accumulated, the system might issue an additional report to
indicate which of the potentially affected parties are Real Affected or Recovered. These indications are
available through the API and the Cisco ANA GUI.