Cisco Prime Nerk 43 User Guide

 
C-39
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
Interface Example 6
Figure C-39 shows an unreachable CE due to a failure in the unmanaged network.
Figure C-39 Interface Example 6
The following failures are identified in the network: 
A Device Unreachable alarm is generated on the CE.
A Cloud Problem alarm is generated.
The following correlation information is provided:
No alarms are generated on a PE for Layer 1, Layer 2, or IP interface...

 
C-40
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
GRE Tunnel Down/Up
Generic routing encapsulation (GRE) is a tunneling protocol that encapsulates a variety of network layer 
packets inside IP tunneling packets, creating a virtual point-to-point link to devices at remote points over 
an IP network. It is used on the Internet to secure VPNs. GRE encapsulates the entire original packet 
with a standard IP header and GRE header before the IPsec...

 
C-41
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
Figure C-41 GRE Tunnel Down Example 1 (Single GRE Tunnel)
When the link down occurs on L2, a Link Down alarm appears. A GRE Tunnel Down alarm is issued as 
the IP interfaces of the tunnel edge devices go down. The Interface Status Down alarms correlate to the 
GRE Tunnel Down alarm. The GRE Tunnel Down alarm correlates to the Link Down alarm.
The system provides the following report:
Root...

 
C-42
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
Figure C-43 shows the Correlation tab of the Ticket Properties dialog box that displays all the alarms 
that are correlated to the ticket, including the correlation for each GRE tunnel and its interface status. 
Figure C-43 Alarm Correlation to GRE Tunnel Down Ticket 
As illustrated, the system provides the following report:
Root cause—Link Down Due to Admin Down
Correlated events:
[GRE Tunnel...

 
C-43
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
Q-in-Q Subinterface Down Correlation Scenarios
Q-in-Q technology refers to the nesting of a VLAN header in an Ethernet frame in an already existing 
VLAN header. Both VLAN headers must be of the type 802.1Q. When one VLAN header is nested 
within another VLAN header, they are often referred to as stacked VLANs. 
A subinterface is a logical division of traffic on an interface, such as multiple...

 
C-44
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
Q-in-Q Subinterface Down Correlation Example 2
In this example, using the devices in Figure C-44:
On device 7201-P1 on Gi0/3, the following subinterfaces are configured: 
–Gi0/3.100
–Gi0/3.101
A local pseudowire tunnel is configured and links Gi0/3.100 with Gi0/3.101 for local switching. 
When the Gi0/3.100 subinterface is shut down by the administrator, the following are generated:
Subinterface...

 
C-45
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Correlation Scenarios
VSI Down Correlation Scenarios
Virtual Private LAN Service (VPLS) is a type of Layer 2 VPN that provides Ethernet-based 
multipoint-to-multipoint communication over MPLS networks. It allows geographically dispersed sites 
to share an Ethernet broadcast domain by connecting sites through pseudowires. Emulating the function 
of a LAN switch or bridge, VPLS connects the different customer LAN...

 
C-46
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  Root Cause Across Frame Relay, ATM, or Ethernet Clouds
VSI Down Correlation Example 2
In this example, using the devices in Figure C-46, the VSI attachment circuit (the interface VLAN) is 
shut down. The expected alarm hierarchy is the same as in Example 1:
VSI Down >
–Pseudowire tunnel 1 down > Pseudowire tunnel 1 syslogs
–Pseudowire tunnel 2 down > Pseudowire tunnel 2 syslogs
–Other related faults
However, because...

 
C-47
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  MPLS Fault Scenarios
Cloud Problem Alarm and Correlation Example 
For some events, when there is no root cause found, a special Cloud Problem alarm is created. These 
events are then correlated to the alarm. If several events trigger the creation of a Cloud Problem alarm, 
one alarm instance is created and all events correlate to it. 
In the example in Figure C-47, two devices that have OSPF configured are connected...

 
C-48
Cisco Prime Network 4.3.2 User Guide
Appendix C      Event Correlation Examples
  MPLS Fault Scenarios
Link Down Scenario 
Ta b l e C - 4 lists the impact calculations and reported affected severities for a link down fault scenario.
Link Overutilized/Data Loss Scenario 
Ta b l e C - 5 lists the impacted calculations and reported affected severities for a link overutilized/data loss 
fault scenario.
Table C-4 Link Down Scenario
Impact and Affected Severity Description
Impact calculation Initiates...