| IfService | 
 This class holds the managed node/ip/service information for valid outage
 nodes. 
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| Interface | 
 This class holds the interface information and list of services that belong
 to the interface. 
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| Node | 
 This class holds the interface which has service information and list of
 outages for the service. 
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| Outage | 
 This class holds the service lost and regained time pair for the
 node/ipaddr/service combination. 
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| OutageSince | 
 OutageSince  holds the temporary storage for data used during
 availability report generation presented in the report. 
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| OutageSvcTimesList | 
 
 This contains a list of service lost/regained set/pair. 
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| Service | 
 This class holds the service information and list of outages for the service. 
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| StandardNamedObject | 
 This class gives a name to the object. 
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