Table Of Contents
Correlation Over Unmanaged Segments
Fault Correlation Across the FR/ATM/Ethernet Cloud
Correlation Over Unmanaged Segments
This chapter describes how Cisco ANA performs correlation decisions over unmanaged segments, namely, clouds.
Cloud VNE describes managing more than one network segment that interconnects with others, over another network segment which is not managed.
Cloud Problem Alarm describes the "cloud problem" alarm, its correlation and provides an example.
Cloud VNE
In some scenarios Cisco ANA is required to manage more than one network segment that interconnects with others over another network segment which is not managed. In such setups, faults on one device might be correlated to faults on another device that is located on the other side of the unmanaged segment of the network or to unknown problems in the unmanaged segment itself.
A virtual cloud is used for representing unmanaged network segments. It represents the unmanaged segment of the network as a single device that the two managed segments of the network are connected to, and has that device simulate the workings of the unmanaged segment.
Virtual clouds support specific network setups. The types of unmanaged networks that are supported are:
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Frame-Relay
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Fault Correlation Across the FR/ATM/Ethernet Cloud
When a Layer 3 or 2 event (e.g. reachability problem, neighbor change, FR DLCI down, ATM PVC down) occurs, it triggers a flow along the physical and logical path modeled on the VNEs. This is done in order to correlate to the actual root-cause of this fault. If the flow passes over a cloud along the `path flow' it marks it as a potential root-cause for the fault. If there is no other root-cause found on the managed devices, then the cloud becomes the root-cause. A ticket is then issued and the original event correlates to it.
Cloud Problem Alarm
For some events, when there is no root cause found, a special alarm is created, namely, "cloud problem." These events are then correlated to the alarm.
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The following parameter can be controlled through the Registry for each event type:
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Note
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BGP neighbor loss syslog
OSPF neighbor loss syslog
EIGRP syslog
CISCO IGRP syslog.
Cloud Correlation Example
In this example two devices that have OSPF configured are connected through a cloud. A malfunction occurs inside the unmanaged network that causes the "OPSF neighbor down" alarm to be generated. In this case the "OSPF neighbor down" alarm is correlated to the "cloud problem."
Figure 4-1 Cloud Correlation Example
On the PE1 device,the "OSPF neighbor down" alarm was received and no root cause was detected in any of the managed devices. A disconnected link inside the unmanaged network caused the "OSPF neighbor down" alarm. The following alarms are generated and correlated:
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