1.ABSTRACT :
Considering an end-to-end approach of
inferring probabilistic data-forwarding failures in an externally managed
overlay network, where overlay nodes are independently operated by various
administrative domains. Our optimization goal is to minimize the expected cost
of correcting (i.e., diagnosing and repairing) all faulty overlay nodes that
cannot properly deliver data. Instead of first checking the most likely faulty
nodes as in conventional fault localization problems, we prove that an optimal
strategy should start with
checking one of the candidate nodes, which are identified
based on a potential function that we develop. We propose several efficient
heuristics for inferring the best node to be checked in large-scale networks.
By extensive simulation, we show that we can infer the best node in at least
95% of time, and that first checking the candidate nodes rather than the most
likely faulty nodes can decrease the checking cost of correcting all faulty
nodes.
2.EXISTING SYSTEM :
Network components
are prone to a variety of faults such as packet loss,
link cut, or node outage. To prevent the faulty components from hindering
network applications, it is important to diagnose (i.e., detect and localize) the components that
are the root cause of network faults, as in . However, it is also desirable to repair the faulty components
to enable them to return to their operational states. In particular, it is
difficult to directly monitor and access all overlay nodes in an externally managed
network,
whose routing nodes are independently operated by various administrative domains.
In this case, we can only infer the network condition from end-to-end
information. Considering an end-to-end inference approach
which, using
end-to-end measurements, infers components that are
probably faulty in forwarding data in an application-layer overlay network
whose overlay nodes are externally managed by independent administrative
domains. A routing tree topology with a set of overlay nodes, since a
tree-based setting is typically seen in destination-based routing (e.g., CAN and Chord ), where each overlay node builds a
routing tree with itself as a root, as well as in multicast routing, where a
routing tree is built to connect members in a multicast group,then monitoring
every root-to-leaf overlay path. If a path exhibits any “anomalous behavior” in
forwarding data, then some “faulty” overlay node on the path must be
responsible. In practice, the precise definition of an “anomalous behavior”
depends on specific applications. For instance, a path is said to be anomalous
if it fails to deliver a number of correct packets within a time window. Using
the path information collected at the application endpoints (i.e., leaf nodes),
we can narrow down the space of possibly faulty overlay nodes. In the above
end-to-end solution, one can tell whether a path behaves anomalously, but
cannot specifically tell which and how many overlay nodes on the path are
faulty. Since we cannot directly monitor and access externally managed overlay
nodes,in order to correct the faulty nodes, we need to contact the administrators
of the corresponding domains to manually check a sequence
of potentially faulty
nodes and fix any nodes that are found to be actually faulty.
3. EXISTING SYSTEM :
Optimality
results for an end-to-end inference
approach to correct
(i.e., diagnose and repair) probabilistic network faults at minimum expected
cost are observed. One motivating application of using this end-to-end
inference approach is an externally managed overlay network, where we cannot
directly access and monitor nodes that are independently operated by different
administrative domains, but instead we must infer failures via end-to- end
measurements. We show that first checking the node that is most likely faulty
or has the least checking cost does not necessarily minimize the expected cost
of correcting all faulty nodes. In view of this, we construct a potential
function for identifying the candidate nodes, one of which should be first
checked by an optimal strategy. Due to the difficulty of finding the best node
from the set of
candidate nodes, we propose several efficient heuristics that are suitable for
correcting fault nodes in large-scale overlay networks.
The process of diagnosing and repairing faulty nodes
in an externally
managed overlay network, in which overlay nodes are
independently operated by multiple administrative domains is predominant. By an
administrative domain, we mean a single administrative authority that controls
a collection of resources (e.g., routers and servers) ]. Examples of externally
managed overlay networks include Resilient Overlay Network (RON) which provides routing resilience toward
Internet path outages, and Service Overlay Network (SON) , which provides
end-to-end quality-of-service guarantees. Both RON and SON deploy overlay nodes
over multiple
administrative
domains that cooperatively accomplish certain network services. To ensure the
availability of these network services, an effective network fault mechanism is
therefore necessary.
4.HARDWARE REQUIREMENTS:
•
System :
Pentium IV 2.4 GHz.
•
Hard Disk :
40 GB.
•
Floppy Drive : 1.44 MB.
•
Monitor :
15 VGA Colour.
•
Mouse :
Logitech.
•
Ram :
256 MB.
5.SOFTWARE REQUIREMENTS:
•
Operating
System : - Windows XP Professional.
•
Front
End :
- Asp .Net 2.0.
•
Coding
Language : - Visual C# .Net.
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