IS-IS impact analysis
overview
IS-IS failures, or apparent
failures, that are detected by
cannot be analyzed in isolation. Rather, those failures
must be correlated with the physical-transport failures that are detected by
IP Availability Manager
in order to determine the root-cause problem that is
underlying all observed symptoms.
analyzes IS-IS and physical-transport failures to determine
whether an IS-IS failure is indeed a root-cause problem, or simply a symptom
(impact) of an underlying physical-transport root-cause problem.
When
detects an IS-IS failure, it checks for any
physical-transport problem that might be causing the failure. If it does not
find such a problem,
focuses its analysis on just the IS-IS domain and performs
the root-cause analysis described in
Chapter 3, “IS-IS Objects and their
Failures.”
If it does find such a problem,
diagnoses the IS-IS failure as an impact and exports the
underlying physical-transport problem and the IS-IS failure to the
Global Manager
.
The
Global Manager
responds by adding the IS-IS failure as an impact of the underlying
physical-transport root-cause problem.
IS-IS and global
impact analysis shows the flow of information between the components in
a
deployment to achieve IS-IS and global impact analysis.
IS-IS and global
impact analysis

Status updates
received from IP Availability Manager identifies the
IP Availability Manager
status updates to which
subscribes.
Object
| Problem-type status
| Event-type status
|
|---|---|---|
1**Indentation indicates
class hierarchy.
2**Perceived as a
problem-type status by
.
| ||
Card
| Down
| |
NetworkAdapter Interface 1 Port
| Disabled,
Down
| |
NetworkConnection Cable
1 TrunkCable
| DownOrFlapping 2
| |
UnitaryComputerSystem Router
1 Switch and so on
| Unresponsive 2
| |
imports status information from
IP Availability Manager
through a remote (proxy) accessor, as shown in
Remote accessor
operation for Network Protocol Manager for IS-IS.
Remote accessor
operation for Network Protocol Manager for IS-IS

“Update object attributes” in
Figure 17
corresponds to “Status updates” in
IS-IS and global
impact analysis and in
Status updates
received from IP Availability Manager. Status updates represent changes
to problem-type and event-type instrumentation attribute values.
Adding
IP Availability Manager
as a source to
causes
to import topology and status from the
IP Availability Manager
. The
provides the
instructions for completing this task.