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  Correlation Scenarios
Device Unreachable on Link Down Event
Figure C-7 illustrates the lab setup for a Device Unreachable on a Link Down event.
Figure C-7 Lab Setup for Device Unreachable on a Link Down Event
Description of Fault Scenario in the Network
The S.2/3 port of PE-East connected to the S.1/2 port of the CE-5 device (also called L1 link) is set to 
administrative status down. This effectively takes the L1...

 
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  Correlation Scenarios
Noncorrelating Events
The noncorrelating event is:
[Link Down Due to Admin Down, PE-East < > CE-5]
This event opens a new ticket in the gateway.
The L1 Link Down event is configured to not correlate to other events. This is logical because the edge 
VNEs identify the Link Down events as [Link Down Due to Admin Down] events. This implies that the 
VNEs know the root cause of the event already,...

 
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  Correlation Scenarios
Multiroute Correlation Scenarios
Figure C-9 displays the lab multiroute configuration setup between P-South, P-North, and P-West 
devices. The OSPF cost is the same along the path from P-South and P-North whether or not it goes via 
P-West; that is, P-South and P-North connect along two paths with equal cost.
Figure C-9 Lab Multiroute Configuration Setup Between P-South, P-North and P-West...

 
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  Correlation Scenarios
The Link Down event is issued by the PE-East VNE (active) as a result of the link down negotiation 
process.
[Link Down Due to Admin Down, P-North < > P-South] event.
The Link Down event is issued by the P-North VNE as a result of the link down negotiation process.
Noncorrelating Events
[Link Down Due to Admin Down, P-North < > PE-East] opens a new ticket in the gateway.
[Link Down Due to Admin...

 
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Figure C-10 displays the events identified by the system in this scenario (L1).
Figure C-10 Multiroute Scenario—L1
Figure C-11 displays the events identified by the system in this scenario (L2).
Link down due to admin downP-North-IOU-161#0:Serial1/3PE-East-IOU-161#0:Serial2/2
PE-East-IOU-161 IP:Serial2/2
PE-East-IOU-161 IP:Serial2/2 PE-East-IOU-161 IP:Serial2/2
PE-East-IOU-161
PE-East-IOU-161...

 
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  Correlation Scenarios
Figure C-11 Multiroute Scenario—L2
Clearing Phase
Enabling the L1 link makes the CE-1 device reachable from the management subnet IP address, thereby 
clearing the Device Unreachable event of the CE-1 device. When the L1 link’s new status is discovered 
by Prime Network, the PE-East device eventually initiates a Link Up event for this link. When the 
administrator enables the Layer 2 link and...

 
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  Correlation Scenarios
Figure C-12 Lab Setup for BGP Neighbor Loss Correlation Scenarios
NoteIn Figure C-12 the link between P-West and PE-North-West is not real and merely emphasizes how 
PE-North-West is connected in the network.
There are two main scenarios that might lead to a BGP neighbor loss event:
BGP neighbor loss due to a Link Down (or an equivalent port down).
BGP neighbor loss due to BGP Process Down or...

 
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BGP Neighbor Loss Due to Port Down
Figure C-13 displays the BGP neighbor loss due to port down scenario.
Figure C-13 BGP Neighbor Loss Due to Physical Port Down (P-West > PE-North-West)
Description of Fault Scenario in the Network
In Figure C-13 the BGP neighbor loss occurs due to a physical port down (in P-West that connects to 
PE-North-West). The relevant devices are PE-North-West, RR2,...

 
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  Correlation Scenarios
Possible Root Cause
1.Prime Network waits two minutes. For more information, see How Prime Network Correlates 
Incoming Events, page 10-4.
2.After two minutes, the [BGP Neighbor Loss, RR2] event triggers the VNE to initiate an IP-based 
flow to the destination IP of its lost BGP neighbor (PE-North-West):
Flow Path: RR2 > P-North > P-West > P-West port is connected to PE-North-West (which is...

 
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Figure C-15 displays the up event that clears all the down events identified by the system.
Figure C-15 BGP Neighbor Up Event that Clears All the Down Events
Variation
In a BGP process down scenario, the BGP Process Down event is identified by the system in addition to 
the BGP Neighbor Loss event.
As illustrated in Figure C-16, the BGP Process Down event causes several events (the BGP Neighbor...